The student is referred for more detailed information on this subject to Qualtrough's "Sailor's Handy Book," where it is treated with special reference to yachts and yacht sailing.
We shall confine our attention chiefly to the two principal types of fore-and-afters peculiar to the waters of the United States, viz.: the two masted schooner, Fig. 515, Plate 123, and the sloop.
The Schooner has a fore and aft foresail and mainsail, both usually laced to booms and gaffs and attached to hoops on their respective masts. It has also a fore and main gaff topsail, triangular in shape, the luff attached to the topmast by hoops; the sails furling aloft at the lower masthead.
The head sails of coasting schooners are variously named according to the position of the stays.
When the forestay goes to the bowsprit cap, or nearly to it, the first head sail from inboard is the jib, beyond which are the flying jib and outer jib.
But if the forestay sets up at or near the knightheads, the sail set upon it is called the fore staysail, and the others are the jib, flying jib, and outer jib.
An additional jib, on the fore topmast stay, is called a jib topsail. Its tack lashing may have a long drift to enable the sail to hoist above the other jibs.
It will be seen from the above that the jib of a schooner is that sail whose tack is nearest to the bowsprit cap.
In our description of manoeuvres, &c., we assume the inner head sail to be a fore staysail.
The staysail sheet and fore and main sheets have their lower blocks strapped to a thwartship traveller. This traveller for the main sheet is a short bar of iron, and for the other sheets extends across the deck, and for the staysail sheet may be a wooden spar. Stout tail ropes or clew-ropes for the staysail and foresail enable those sails to be held to windward, if necessary, in tacking.
The foresail may be a combination of "boom and lug," in which case the forward part of the foot has the usual
boom and traveller, and the clew of the sail extends much further aft than in the ordinary type. Such a sail sets better than a common boom foresail, particularly on a wind, when the boom foresail sheet must be trimmed so flat to fill the foresail and fore gaff topsail, that much of the propelling power is lost. But the boom and lug foresail requires more attention in tacking. The lug foresail, without any fore boom, is rarely seen in our coasting craft.
The main mast of schooners is stayed by a triatic stay from one lower mast head to the other. Large schooners may have in addition a double stay to the deck, the ends setting up with runners and tackles at the waterways, abreast the after part of the fore rigging. The lee stay must be overhauled, when under way, to clear the foresail.
The main boom topping lift is usually single, shackled to a bolt in the after part of the main masthead, the lower end fitted with a whip or whip and runner with a block on the outboard end of the boom and a sheave through the boom for the hauling part. The topping lift may be double in large schooners, in which case they come further in on the boom, and the lee one must be overhauled when the sail is set.
The fore boom topping lift is a pendant supporting the boom end. The upper end of the pendant is fitted with a whip or tackle, upper block hooked under the main trestle trees, fall leading on deck.
Halliards.-The fore and main peak halliards are generally rove through three single blocks on the gaff and two double blocks on the mast-head placed vertically one above the other, the distance apart varying with the length of the gaff. The hauling part leads through one sheave of the upper block to the outer block on the gaff, back to the upper block on the mast-head, thence to second block on the gaff; then through one sheave of the lower masthead block and the inner gaff block, finally the standing part reeves through the remaining sheave of the lower masthead block and to the deck, where a purchase is fitted to the end.
Throat halliards consist of a treble block aloft and double block at the jaws of the gaff, the standing part of the halliards fitted with a purchase which generally travels on the topmast backstay, similar to the topsail halliards of a square rigged vessel.
Reef Pendants for a boom mainsail consist of
a long pendant with a Mathew Walker knot in one end. The pointed end reeves up through an eyebolt on one side of the boom, through a reef cringle in the leech and down on the opposite side through a sheave on the boom. When reefing, the end of the reef pendant is hitched to the hook of the outer reef-tackle block, the inner block of the reef tackle hooking to an eyebolt under the boom.
There are no reef pendants required for the foresail,
ordinary reef earings being passed through the reef cringles lower when required, the end of the fore boom being generally lowered on deck while the reef is being taken.
Gaff Topsails.-The gaff topsail sheet reeves through a sheave in the gaff end, and thence through a block at the jaws of the gaff, and to the deck.
The halliards reeve through a block at the topmast head, or sheave in the topmast. The tack leads from the tack of the sail to the deck.*
The clewline and downhaul, in one, is secured to the clew of the sail and reeves thence through a leader at the head and down on deck.
The Sloop has but one mast, placed about two-thirds the vessel's length from the stern. The mainsail is like that of a schooner. The sloop also carries a gaff topsail similar to those already described.
The jib of a sloop sets on the forestay, which in this case goes to the bowsprit cap. A jib topsail is carried usually, in addition, being set upon the topmast stay.
The topping lifts, halliards, &c., are similar to those already described for schooners.
Getting under way.-Schooners.-Heave short, loose and hoist the mainsail, keeping the peak square with the throat until the throat is up. If the mainsail has two topping lifts, see that the gaff is hoisted between them. If
the topping lift is single hoist the gaff so that it will be to
leeward of it; the peak can then readily be dropped in case of any accident in casting. **
Get the final pull of throat and peak halliards on the purchase on the standing parts. Now, hoist the foresail and loose the head sails.
To cast to starboard, heave up the anchor, putting the helm a starboard, main boom steadied over to starboard, fore sheet trimmed down, but playing on the traveller; hoist the staysail, or staysail and jib, with the port sheets
aft. When she has paid off sufficiently to starboard, "Draw" the head sheets, right the helm, and trim the fore and main sheets.
If blowing fresh the foresail may not be set till after casting.
If intending to wear and stand out before the wind, the
peak of the mainsail may be left down until after casting.
In a close place, with little room astern, hoist the head sails before breaking ground.
* Or the gear of the gaff topsail may be named on the principle adopted with studding-sails; when the outhaul is known as the tack and the tack is called the sheet, which is the case on board many coasters.
** A peak downhaul should always be fitted to a gaff; it is rove through a bull's eye at the gaff end, ends of the downhaul leading to cleats on opposite sides of the boom.
Sloops.-Heave short, hoist the mainsail, clear away the jib; when ready to trip, to cast to starboard, put the helm a starboard, hoist the jib, haul the sheet to port; shove the main boom well out over the starboard quarter. Heave up, and when she has paid off sufficiently, right the helm, "draw jib," haul aft the main sheet.
If to stand out before the wind, leave the peak of the mainsail down until after wearing around, and shift the helm when headway begins.
Riding to the tide, in getting under way, use the helm as in casting a square rigged vessel; in casting to starboard, put the helm aport until she gathers sternboard, when it must be shifted.
Coasting vessels as a rule do not take the trouble to ease off the main sheet in casting, simply guying the boom well over to leeward, sheet trimmed ready for the first stretch.
Tacking. - Schooners. - Under ordinary circumstances, moderate breeze and smooth sea, clew up the fore gaff topsail, "hard a lee" very gradually, keeping all sheets fast just as long as they will do any good, haul all over as she comes head to wind, especially avoiding keeping the staysail sheet one instant to windward if she will pay off without its assistance. Trim the jibs down at first quick and flat, but as she gathers headway ease them slightly.
If the schooner is out of trim, or a dull sailer, or if the circumstances of wind and sea are unfavorable, the staysail sheet is held to windward to assist in paying off, and the clew rope let go at the order "Draw" or "Let draw." If she goes around with a stern board, the helm must be shifted.
When around on the other tack set the fore gaff topsail to leeward of the triatic stay by unbending and dipping the sheet aloft. In making short legs, the fore gaff topsail is not set, as a rule.
If the schooner has a boom and lug foresail, a couple of hands can take care of that part of the sail not controlled by the boom and traveller. A lug foresail requires more force, and the sheet must be hauled over briskly to avoid making a back sail of it; it is likely to foul the pins, &c., on the mast band, and is altogether unsuitable for coasting vessels with small crews. The boom foresail requires no attention.
Should the staysail not be fitted with a traveller, it will probably be because the clew comes very far aft, which will require considerable overhauling of one sheet and hauling in on another, and this is seldom done in good time. A decided disadvantage of having the clew come abaft the foremast is that it throws the wind out of the lull of the foresail.
One hand ought to take care of the flying-jib sheets on a schooner not over 100 tons; if blowing fresh, the flying-jib (and gaff topsails) would probably be in.
Many schooners are fitted with a "boom jib" (Fig. 516), the foot of the sail being secured to the boom. The outboard end of the boom is fitted with a gooseneck, the lug of which slides on a short iron rod on top of the bowsprit. When the sail is hoisted, the outer boom end is hauled aft on the traveller by a whip and runner belayed at the knightheads, which gives the foot of the sail the proper stretch.
The jib sheet is rove through a double block on the inner end of the boom, and two single blocks in the waterways-one on each side; standing part made fast to one single block, through one sheave of the boom block, then through the other single block, back through the second sheave of the boom block and the first single block, the end being belayed on the same side of the forecastle as the block which carries the standing part. By this arrangement the boom end travels to and fro on the sheet, avoiding the inconvenience and danger of a traveller, with its sheet sweeping the deck. To hold the jib to windward if need be, a tail rope is fitted to the inner end of the boom, clear of the double block. A light topping lift from the fore trestle-trees supports the inner end of the boom.
Sloops.-The vessel going a good full and by on the port tack, ease the helm down, when hard a starboard and the sloop is nearly head to wind, let go the jib tail rope (jib fitted with a traveller).
If she hangs in stays, trim the jib sheet to windward again as she passes the direction of the wind, in this case keeping it over to starboard, and shove the main boom well over on the port quarter. As she gathers headway on the new tack, "Draw jib," let go the clew rope and the sheet will fly to leeward on the traveller; trim aft the main sheet and right the helm.
Should the sloop in tacking gather a stern board, the helm must be shifted and put hard a port (in this case) till she gathers headway again.
A large centre-board schooner or sloop in a fresh breeze may require part of the board hauled up on going about, to prevent too much strain on the board and trunk, and to have the craft stand up better. These vessels will swing around in stays much faster than a keel vessel.
To Wear. -Schooners.-Clew up the main gaff topsail, if set, drop the peak of the mainsail, up helm and ease off the main sheet. While paying off, round in the slack of the main sheet just enough to keep the sail full; when the wind is aft shift over the boom and head sheets; hoist the peak of the mainsail, haul out the gaff topsail, and meet her with the helm as she comes to. The head sheets, when shifted over, should not be trimmed down flat, as that tends to prevent her coming to.
For a sloop, proceed in a similar way, clewing up the gaff topsail and dropping the peak as necessary.
Gybing.- Having the wind on one quarter, if a change of course or of the wind itself brings the wind on the other quarter, the main boom must be shifted over, and the operation is called gybing. To gybe a main boom, blowing fresh, is an operation requiring much skill, as it is not unfrequently attended with accidents-such as springing the boom, splitting the sail, or wrenching the masthead or jaws of the gaff.
In a smooth sea and with a moderate breeze, with the wind aft and the boom guyed out on the starboard quarter; give a careful sheer with a starboard helm, hauling the main sheet flat aft and the boom nearly amidships; then take a good turn with the sheet, shift the helm handsomely to port till the wind is on the starboard quarter, when the main sheet may be slacked off briskly but kept under control, and the vessel steadied to her course.
As a rule, the peak of the mainsail should be dropped, if only to get the gaff to leeward of the topping lift, besides rendering the operation of gybing much safer.
Many fore-and-afters (particularly sloops), instead of gybing, will, under these circumstances, frequently luff into the wind and come around on the other tack, thus:
The boom being off to port, luff up gradually with a port helm, hauling in the main sheet and getting the jib sheet in, but not enough to fill the sail. When she is head to wind the jib sheet is kept to port just enough to pay her off on the new tack, and as the boom comes over, the main sheet is eased off, keeping headway all the time, if possible.
A flat bottomed sloop drawing little forward will come around in rough water almost always without hauling in much of the main sheet, and, if she has a jib traveller, without hauling in the jib sheet at all, taking care to catch her at the right time with the clew rope, to make the jib assist in paying her head around. A deep keel schooner would require more management.
Wing and Wing.- In running with the wind aft, schooners with the main boom guyed out on one quarter and with the fore boom guyed out on the opposite side, are said to be "wing and wing." The main boom is guyed out by a boom pendant, into which hooks a tackle (boom-tackle) taken forward of the main rigging and inboard. The fore-boom is guyed forward by a similar pendant and tackle, the latter hooked to an eyebolt well forward. Small craft may use a line rove through a block on the bowsprit. The fore boom topping lift must be overhauled as required.
In running with the wind on the quarter or aft, accidents from unexpected gybing would probably be serious, and for this reason very careful steering is required.
When running in fore-and-aft vessels, to avoid the yawing and difficulty of handling the helm when before the wind, particularly in sloops, it is advisable, when circumstances
permit, to "tack to leeward," by bringing the wind well on one quarter, sailing a certain part of the required distance, and then accomplish the balance of the run with the wind on the other quarter.
Running in a gale, bear in mind the use of a drag astern, as dwelt upon elsewhere (page 479).
Squally Weather, Reefing.- In sailing a fore-and-aft vessel by the wind in squalls, it is usual to touch her up in the wind. A careful person ought to be at the helm in carrying sail in squally weather, when it is necessary to luff and touch the sails. Should the wind prove variable, in direction as well as in force, sail ought to be made snug, for if a squall should come suddenly on the quarter it would be too long a luff before the sails touch, and if it comes out ahead they will then be thrown aback.
To reef the mainsail, bring the vessel to the wind, hauling in the main sheet; lower the throat and peak halliards till the reef band is below the main boom, pass the tack lashing at the luff, hook the reef tackle to the reef pendant, and haul out the reef band close along the boom. Pass an earing through the reef cringle at the leech, come up the reef tackle and shift the pendant to the second reef cringle, in readiness for another reef. Tie the points around the foot rope of the sail, never around the boom. Hoist the sail finally, getting the throat taut up before the peak.
When the third (close) reef is taken, the pendant is left rove through the cringle with the reef tackle hauled taut, and acts then as a backer to the reef earing.
To take the balance reef, if fitted, ease the peak halliards enough to let the jaws of the gaff come close down, pass a lashing around the throat, fit and tie the points around the foot of the sail, and pull up the peak halliards.
The balance reef extends from the close reef-band nearly to the throat.
To Reef the Staysail (or Jib).-Being by the wind, haul down the sail, bringing the reef cringle to the bowsprit and lashing it, unhook the sheet block and hook it to the proper cringle on the leech; tie the reef points around the foot of the sail; when ready, hoist and trim aft the sheet. If fitted with a bonnet, come up the lacing or keys, and take the bonnet off, securing the tack and shifting the sheets as before.
To turn out Reefs. Bring the schooner or sloop to the wind, if necessary, cast off first the reef points, then the tack lashing, and finally the reef cringle lashings (earings); overhaul the reef pendant; man throat and peak halliards and sway the sail up to a taut leech.
To Heave to. Moderate weather. Haul flat aft the main sheet, putting the helm down, and haul the staysail sheet to windward; if a boom foresail, ease off the fore sheet to spill the wind out of the sail.
Man Overboard. If on a wind, put the helm down, throwing overboard a life buoy or grating to the man, bring the vessel around on the other tack and stand toward him.
If running free, say wind on starboard quarter and plenty of room, luff around by all means, on the opposite tack; haul in roundly the main sheet, putting the helm a port; let her luff around, but keep the jib sheet to windward (port) when about and the main boom trimmed flat. Lower the boat in stays.
Circumstances might require the vessel to heave to on the same tack (starboard tack in this case), in which event perform only the first half of the evolution, and meet her with the helm and head sheets as she comes to, but she will be further from the man, and this is not recommended. The boat in this event would pull off the weather beam.
Laying to in Heavy Weather. Concerning the best mode of laying to in heavy weather, too much depends upon the type of vessel and state of the wind and sea to lay down any fixed rules. An ordinary keel schooner of 150 to 200 tons, which has been running under a close reefed mainsail, reefed foresail and reefed fore staysail, having the hatches battened down and everything secured about the decks, is brought to the wind by easing down the helm, and with all hands on the main sheet, watching for a smooth time to put the helm down, and hauling down the staysail (generally) as she comes to. The mainsail is then lowered and the fore sheet hauled aft.
In a gale of wind, a sharp built schooner is hove to under double reefed foresail, with the sheet trimmed as on a wind, or flat, if necessary to keep the vessel from head reaching too much, and to keep the sail from shaking as she comes up head to wind. When the foresail is full, the vessel head reaches enough to keep up a certain amount of steerage way and consequent action of the rudder.
In some schooners it is frequently essential to hoist the head of the mainsail to assist in keeping them to.
Most of them are provided with a storm "trysail," similar in shape to the storm mizzen of square-rigged vessels, and used for the same purpose.
The helm should not be lashed alee, but tended as circumstances may require, and the vessel should keep steerage way if possible.
A flat-built schooner is often hove to under a balance-reefed mainsail; but if this be done she must be very flat, and when she will not lay to, in any way, under a foresail.
Shallow-built vessels, and such as have flat floors, are much more liable to be upset in a heavy sea than those of a different construction. This arises from their having so little hold upon the water, notwithstanding their great
stability in a river, or smooth sea, where it would be almost impossible to capsize them in carrying sail.
Large sloops are about the least desirable seagoing craft, their long mast and boom rendering them uncomfortable rough-weather boats, though in smooth water and going to windward they will be found the fastest. Such vessels are hove to under a few hoops of the mainsail and a storm jib, though here again the difference of model may render more after sail (as a storm trysail) necessary, and the boom may have to be well eased off. In this case, and indeed in any seaway, the boom should be well topped up.
The usefulness of a drag as a sea-anchor in riding out a gale may be reiterated here. The form of drag which probably gives the best results is that of a stout conical bag of canvas, with a heavy iron ring at the mouth. The ring may be hinged for facility of stowage, but in such a way that it will only close in the direction of the apex of the cone. The drag is fitted with a bridle at the mouth, to which is secured the riding hawser or cable; a tripping line from the point of the cone allows the drag to be canted for hauling in. The iron ring at the mouth should be heavy enough to keep the drag below the surface of the water.
Anchoring. Coming in on a wind, round to to leeward of your berth, haul down the head sails, and as she comes to the wind, meet her with the helm; keep her head to wind till headway is lost, then let go the anchor, and as she drops astern pay out the chain; lower and furl the sails.
If running to an anchorage before the wind, get the head sails and foresail (a schooner) down in good season to present no opposition to coming to.
When the helm is put down, drop the peak of the mainsail if blowing very fresh, haul the main boom amidships, and when she comes head to wind keep her so till headway ceases, then let go the anchor and pay out the chain as she takes it.
Beating in on a strong flood, lower fore and mainsail, wear around under jib, and when head to tide haul down jib and let go the anchor.
The Topsail Schooner. A class of vessel not especially considered in these notes may be briefly referred to here.
In getting such a vessel under way the yards are braced abox to pay her off; in tacking, the yards are handled like the head yards of a square-rigged vessel, and by the same orders. In running, the topsail, close-reefed, will be found a useful sail, but the reefed fore staysail and main trysail (or close-reefed foresail, according to the model) should be ready for setting in case it becomes necessary to heave to.
It must be recollected that the lee sheet of a schooner's topsail should be the first clewed up, otherwise it may get over the lee yard-arm, on account of the sail having
proportionally more spread at the foot than square-rigged vessels in general. Again, a schooner's weatherbraces must not be too taut, from the liability to part, or to carry away the yard, by the spring of the masts. In squally weather the square sails should be furled.
The topsail schooner rig is almost entirely superseded on the coast of the United States by the hermaphrodite brig.
Yacht Rigs and Sails. A cutter is similar to a sloop, but with a movable bowsprit, fitted to rig out or in, jib set flying. Her fore staysail is called a foresail.
A yawl differs from a cutter in having a small mizzen-mast, stepped close to the stern, with a lug or sprit sail set upon it, the sheet led to the end of a bumpkin projecting astern.
A gaff topsail for a yacht is similar to a coaster's, or it is
four-cornered, has the head laced to a yard, and the halliards bent on at a point determined by the shape of the
A jib topsail is a light jib set on the topmast stay.
A balloon jib is a very large jib of light stuff, extending
from the bowsprit end to the topmast head, clew extending
A spinnaker is a light triangular sail, the foot of which
is extended by a boom goosenecked to the mast, and rigged out on the side opposite to the main boom, the sail being
set on the side opposite to the principal sail on the mast. The halliards lead through a block at the topmast head, the outhaul to the end of the spinnaker boom; the boom itself is fitted with a forward guy from the bowsprit end, an after
guy (or brace), and a topping lift.
Some yachts have a light temporary gaff goosenecked at
the forward side of the mast-head, about the height of the
regular gaff; this gaff is fitted with hoops for the head of the spinnaker, which in this case is a four-cornered sail
and is called a shadow. It may be set in triangular form by keeping fast the head outhaul. When not in use the shadow
gaff hangs up and down the mast by its gooseneck.
Water sails, usually triangular, may be set under the
A ring tail, usually triangular, is set abaft the main sail,
between the gaff and boom-the halliards going to the peak and the sheet to a block at the end of the main boom, or to the end of a spar rigged out on the main boom.
HANDLING VESSELS UNDER STEAM;
OR STEAM AND SAIL.
IN previous chapters we have considered the handling of vessels under sail alone, and with reference to those cruisers whose form and disposition of canvas enable them to manoeuvre under sail like ordinary sailing vessels.
In applying what has been said to steam vessels of war, it must be borne in mind that steamers under canvas never fulfil all the conditions looked for in quick working ships. This is partly due to the steamer's form, to a reduced sail area for a given amount of tonnage, to the mode of masting, the drag of the screw, the screw aperture, and other causes.
Vessels of a similar type may differ widely in their qualities under canvas for the same point of sailing, and it would be beyond the scope of a book of reference to enumerate, even for vessels of a single class, peculiarities which are best learned in handling them.
Getting Under Way.-In getting under way under steam, the square sails are not usually set, but the head sails and spanker should be cleared away for assistance in casting. The mast covers should be put on and the mainsail covered, if left bent. Generally the mainsail is unbent and the gear unrove, unless intending to proceed under sail after making an offing. Put on the cover of the main topsail, if used. Reeve off the cat and fish.
Having notified the senior engineer in good time to light or spread fires, when steam is reported ready, call:
Bring to, unbit, and heave around.
The time required from lighting fires until steam is up may be from one to two hours with anthracite coal. In using bituminous coal with forced draft and other favoring conditions, steam may be raised in much less time.
With good banked fires the time required to spread them and get up steam ought not to exceed twenty minutes.
If a long and heavy heave, give a few turns of the engine now and then slowly to assist the bars. Should the anchor prove difficult to break out, give her a turn ahead, sending
word to the navigator* to stopper the cable. When up and down, the ship by moving ahead will certainly trip the anchor, when it may be hove up, catted and fished. The vessel should not "go ahead fast" until the anchor is catted, as it is liable to hook under the fore-foot, and endanger the cat-head.
ONE BELL, signifies to go Ahead slow,|
TWO BELLS, signifies to go Stop.
THREE signifies to go Back.
FOUR signifies to go Ahead fast. **
As soon as the anchors are secure, pipe down, and set the watch to work clearing up the deck, cleaning the anchors and chains, and paying the latter below.
If the steamer had been riding to an ebb tide you may find some difficulty in turning; if practicable, start ahead, and when clear of everything give a sheer with the helm and run up the jibs to pay her round, or she may be backed astern against the helm, using the jibs and spanker whenever they will be of service.
In a small harbor, or a close berth, a propeller may be turned by putting the helm hard over, when at short stay, and going ahead slowly, the water thrown from the screw having effect on the rudder in the same direction as if the vessel were going ahead.
TURNING AGENCIES IN SCREW STEAMERS.
In single screw ships, the rudder, the screw, the wind and sea, and the pitching of the vessel influence the direction of the ship's head. Each of these factors is variable in the extent of its influence, excepting where the results are due, as cited below, to the shape of the underwater body, or to the shape and size of the rudder.
I. The effect of the rudder depends upon the amount of the rudder angle, size and shape of the rudder, and form of the underwater body of the ship, especially of the run. The rudder effect depends further upon the speed, and finally upon the force and direction of the screw current.
Through the latter conditions, the rudder effect is made to depend upon
* Under recent orders limiting the employment of pilots, the navigator cannot usually be spared to look out for the ground tackle forward. His place there is taken by a watch officer.
All steam vessels would be more effectually managed, when under steam, if provided with a pilot house forward.
** Modifications of these will be found very useful; for example, one bell repeated, means slower; four bells repeated, full speed; two bells repeated, "done with steam" (after anchoring or making sail); and when under banked fires two bells means "spread fires"
II. The effect of the screw, the above being indirect effects of the screw upon the turning. Other effects will be considered at some length further on.
In double screw ships the turning effects, such as they are (in view of the greater distance of the screws from the ship's side and rudder), are made to counterbalance each other by causing the two screws to revolve in opposite ways to drive the ship in a given direction, ahead or astern.
III. The effect of pitching on the ship's head is indirectly through the effect of draft on screw and rudder, and directly through the heel imparted to the ship.
IV. The turning effects of wind and sea are due directly to the pressure they exert on the forward or after body, and indirectly to their influence on the ship's speed and heel.
Each factor, then, affects the ship's head, in part directly, and in part indirectly, in connection with one or more of the other causes mentioned.
Assuming that there is neither wind nor sea, the features in single screw ships which produce turning effects are the screw and rudder. We shall consider these causes separately, and the effects of the screw in particular.
We note first that the screw may be either right or left-handed.
A right-handed screw is one which, viewed from aft, turns with the sun to drive the ship ahead. This is the screw in common use on American vessels, and is the one discussed throughout this chapter.*
Fig. 1 shows a vessel fitted with a right-handed screw, an elevation of the screw itself being given below the plan of the ship.
* The effects of a left-handed screw are precisely contrary to those of a right-handed screw.
DIRECT TURNING EFFECTS OF THE SCREW.
The direct turning effects of the screw are due:
(a.) To the difference in resistance of the water to the upper and lower blades; (b.) To the pressure of the screw current upon the after body when the engine is reversed; (c.) To the lateral pressure of the screw stream upon the rudder-post and rudder when the vessel is going ahead.
(a.) Difference in Resistance to the Upper and Lower Blades. When the vessel
starts slowly ahead, the water acted upon by the blade A, Fig. 1, presents a certain resistance to that blade. The water acted upon by the ascending blade D is of gradually decreasing density, while the lower blade C works in the most dense and least disturbed medium, and the descending blade B is gradually meeting an increased resistance. The resistance to the lower blades being greater than that experienced by the upper blades, the centre of shaft being the centre of effort, will incline to move in the direction of least resistance (the direction of the upper blades, shown by the arrows, Fig. 1), and as the stern of the ship holds this centre of effort, it must tend in the same direction, to the right (to starboard), so that the vessel's bow goes to the left (to port).
Moreover, when pushed aside by the lower blade, the denser strata of water experience a speedier inflow than water disturbed by the upper blades; partly owing to the greater density itself and partly on account of the sharper lines of the lower part of the run which permit such quicker inflow. This is an additional reason why the lower blades should experience the greatest resistance, and it therefore increases the tendency of the stern to go to starboard, bow to port.
If the ship is backing, contrary effects obtain, the stern going to port, bow to starboard, on account of the differences of pressure above described.
The wake current, occasioned by adhesion and friction when the ship is moving ahead, dams up the upper surface of the screw current, checking its motion to the rear. In many vessels, this surface indraught astern is very noticeable when the vessel is going at full speed. Its effect is to increase materially the resistance experienced by the upper blades. The "wake" current, therefore, acts in opposition to the effects due to greater density of the lower water strata.
The resultant of the unequal pressures on the upper and lower blades, and hence that part of the direct turning effect of the screw, depends upon the form and sharpness of the run, the draft, the number of revolutions, and the immersion of the screw.
When the water is just being set in motion, i.e., when
the engine begins to move ahead, the first named cause of turning effect is at its maximum (unequal densities). When the speed increases, the second cause (quicker inflow in the lower strata) attains its maximum, but at the same time the backing up effect of the screw current upon the upper surface of the screw stream increases with great rapidity. Great draft and sharpness in the lower part of the run assist the wake current to equalize the resistance to the upper and lower blades.
(b.) Effect of Screw Current on After Body in Backing. When the engine is reversed, the water thrown by the blades moving over to port and downward strikes the lower part of the port side of the run, while the blades which are rising on the starboard side direct their stream against the starboard after body at, or even above the height of the water line. But since at the last named point the screw current, owing to the greater breadth of the ship, strikes at right angles to the vessel, it is therefore of greater effect than the result produced on the other side, where the current from the descending blades impinges, upon the sharp form of the lowest part of the run, and can only exert there a small portion of its strength. Hence, in backing, the screw current tends to push the stern to port, bow to starboard. This increases the effects which we were led to expect under (a) from the difference in densities, and therefore a screw in backing will have a greater effect upon the ship's direction than when the engine is working ahead.
(c.) Pressure of Screw Current on Rudder-post and Rudder. When the engine
is working ahead, the blade moving to starboard and downward directs its stream against the lower starboard side of the rudder-post and rudder; the blades moving to port and upward, send their stream against the upper port side of the rudder and rudder post. As the rudder is usually broader at the bottom than at the top, and as the stream from the upward moving blades meets with the least resistance and distributes itself with the least effect, it follows that the current from the blades moving downward has greater influence than the stream from the upward moving blades.
The effect will be greater or less, according as the rudder happens to be turned toward the blade moving downward and inward, or toward the blade moving upward and outward.
With the helm amidships, the effect of the screw current on the rudder-post and rudder, ship moving ahead, is to turn the stern to port, bow to starboard. This effect is therefore opposed to the results due to the moving of the screw blades in media of different density, while it unites with and increases the effects due to the wake current.
The greater the width of the lower half of the rudder in proportion to the upper half, and the more the after portions
of the screw blades incline to the rear, the greater will be the turning effect above noted.
The final resultant of the direct turning effects of the screw will therefore depend in different ships upon the relative importance of the elements above described.
II.-INDIRECT TURNING EFFECTS OF THE SCREW.
These effects are due to the influence of the screw upon the steering powers of the rudder:
(a.) By causing the speed of the ship and consequent way current with its pressure on the rudder; (b.) By causing the pressure of the screw current upon the rudder when the ship is moving ahead; (c.) By suspending the rudder effect when the ship is moving ahead with the engine working astern, the way current being thrust aside by the screw current.
Of the cause and effect in the first case (a), it need only be said that the ship's speed itself is affected in turn by the rudder, speed decreasing as rudder angle increases. There is therefore here, within certain limits, a reciprocal action.
Under (b) may be noted that the screw current increases the effect of the way current on the rudder when the ship is moving ahead. Both screw and way current are strengthened by increase in the number of revolutions.
The effect of the number of revolutions on the turning power of the rudder, as expressed by the time and diameter of turning in a circle, has been investigated with the German corvette "Hertha," with the following results:
In regard to the time of turning.-Change in the number of revolutions with different rudder-angles, had great influence on the time of turning:
Change in the number of revolutions when the engine is moving slowly is of greater proportionate influence on the time than an equal increase in number of revolutions when moving at great speed.
In regard to the diameter of the circle.-Change in the number of revolutions has but slight effect on the diameter.
The ratio of revolutions to diameters as observed in the "Hertha" at a mean rudder-angle of 20° was as
66 : 62 : 46 : 30 : 18 = 1.21 : 1.17 : 1.63 : 0.97 : 1.
Hence the time of turning varies inversely as the speed, and the diameter varies directly as the speed. The greater the number of revolutions the less the time and the greater the diameter of the circle.
Under (c) it may be said that in vessels moving ahead the suspension of the regular rudder effect due to a reversal of the engines will be more or less complete according to the relative value of the opposing forces. The screw stream being thrown forward, tends to push aside and away from the rudder the way current coming from forward, due to the ship's onward motion. The regular steering effect of the rudder decreases, while the turning effects of the screw become, in most cases, the controlling force.
Apart from influences due to wind, sea; and pitching; the greater the rudder surface and angle, the less the diameter of the screw, the smaller the number of revolutions, and the sharper the upper immersed part of the run-the greater will be the steering effect of the rudder. Under reverse conditions, the greater will be the turning effect of the screw.
To summarize the results due to the screw alone, we may say
1st. That the screw has its greatest effect upon the ship's head in backing.
2d. That the screw has its least effect upon the ship's direction when going ahead, and that effect decreases as the vessel gathers headway. See also note, p. 544.
3rd. That these effects are greatest when the ship's draft is light, the screw being, however, immersed.
Racing. What is said throughout this chapter of the screw effect presupposes that the screw is properly immersed. If this is not the case the effects may be precisely contrary to those described. No data obtained for a given ship at her normal draft can be relied upon when the vessel is badly out of trim or very light.
Chief-Engineer Isherwood, U. S. Navy, observes that inasmuch as the screw current is due to the slip, its strength and effects will depend entirely upon the amount of said slip.
The same authority points out the increase in the screw current, and its consequent effect on the rudder when the vessel is in very shoal water.
One can scarcely fail to notice the different effect of the screw motion on the wake when in shoal water, as compared with the appearance of the water astern when off soundings.
It is to be noted also that the effect of the screw upon the rudder depends very much upon the distance of the
latter from the former. If, for any special reason of construction, or for the purpose of experiment, the rudder is placed at an unusual distance from the screw, the effects of the screw current on the rudder will be materially diminished.
Turning Effect of the Rudder Alone. The rudder, considered apart from the screw, exercises its usual effect upon the ship's head, the bow turning to starboard with a port helm when going ahead (Fig. 2), and to port with the same helm when making a sternboard, the effect of the rudder being greatest when the ship has headway.
Conclusions. Recorded experiments with the Bellerophon, Lord Warden,* Friedrich der Grosse (See Appendix L), and other vessels of great draft, high speed, and moderate sized rudders, show that such vessels, when moving at full speed ahead, have a tendency to fall off in the opposite direction to that taken when they are just starting or moving slowly ahead. This is due chiefly to increased resistance to the upper blades.
Such vessels, when backing, usually take an immediate and decided sheer, due to the screw effect, but increased perceptibly by a favoring helm. If, while backing, the helm is laid to counteract the screw tendency, it must be done quickly, for when the ship has once taken the sheer due to the screw, she may respond but slowly or not at all to the intended action of the rudder.
In vessels of medium size and speed, sharp in the upper part of the run, and with fair sized rudders, the results to be expected may be expressed in tabular form, as follows:
* In the essay, " Few Years Experience with the Screw Propeller," by A. J. Maginnis-Navy Scientific Papers, No. 12-the writer states, as a general rule, that the resistance to the upper blades becomes greater than the resistance to the lower blades at high speed, requiring starboard helm to correct the tendency of the screw when going ahead. This extreme deduction is not borne out by any known American data, but it is verified in the case of the deep-draft British iron clad "Lord Warden," which carries at a speed of nine knots one-half to three-quarters of a turn of port helm, her screw being left-handed. (See "Naval Tactics on the Open Sea," by Capt. the Hon. E. R. Fremantle, R. N.)
EFFECT OF RIGHT-HANDED SCREWS ON THE STEERING
OF STEAMERS OF MEDIUM DRAFT AND SPEED.
|AHEAD SLOW, or JUST STARTING
||AHEAD SLOW, or JUST STARTING
||Screw drives stern to starboard.
Ship answers starboard helm quickest.
|AHEAD, FULL SPEED
||AHEAD, FULL SPEED,
||Tendency of stern to starboard decreases, and may disappear. See also foot-note, page 544.
|ASTERN, FULL SPEED
||ASTERN, FULL SPEED
||Screw draws stern to port.
Ship answers starboard helm (for stern-board) quickest.
||ASTERN, FULL SPEED
||(a.) Helm amidships. Screw draws stern to port.
(b.) Helm hard-a-port. Ship's stern goes to starboard.
stern goes to port quickly, and to a large angle.
(c.) Helm hard-a-starboard. chip's
||AHEAD, FULL SPEED
||Screw drives stern to starboard.
Ship answers starboard helm quickest, and as if under headway.
In such right-handed screw ships the port helm may then be called the weak helm, and it is so regarded.
For vessels of medium size, draft, and speed, it seems to be admitted that-
1st. When the screw is reversed, the rudder will act as if the vessel were going astern, even though she have headway.
2d. When the screw is going ahead the rudder will act as if the vessel were going ahead, even though she have sternway.
3rd. The faster the vessel is moving in the opposite direction to that in which the screw is acting, the less powerful will be the action of the rudder.
Figs. 2 and 3 are designed to illustrate the reverse effect in the first case; Fig. 2 showing the ship's head affected by the helm alone, Fig. 3 the result of reversing the engines.
Figs. 4 and 5 are from the reports of trials made by Professor Reynolds on the steamer Melrose in 1877 and published in the Engineering. The ship going ahead full speed, her engine being suddenly reversed and helm put hard a port, the vessel's head turned twenty-eight degrees to port before the ship came to a standstill. Repeating the experiment, but putting the helm a starboard, the ship's head turned forty degrees to starboard before the headway ceased. The courses taken in both cases being directly opposite to that which the rudder would have steered the ship under ordinary circumstances. Compare also Hankow experiments, Appendix L.
Comparative Effects of Rudder and
Screw. The greatest effect on the ship's head is that of
the rudder when the ship is going full speed ahead; next
in importance is that of the rudder when the ship is moving
at full speed astern. Of the effects produced when the
engine is working in one way and the ship moving in the
opposite direction, the most important is obtained when the
screw is backing. But even at
its greatest, the reverse effect of
the rudder due to the screw is
often feeble, differing in different
ships, and even in the same ship.
under varied conditions of draft.
Should there be wind and sea, when a danger has to be avoided, a ship bringing herself to a standstill by reversal of her engines should be regarded as partly at the mercy of influences which would be easily controlled by the rudder if the ship and screw were moving in the same direction. During the interval before coming to a standstill, screw, rudder, wind, and tide may balance, and the ship move in a straight line till stopped, or any one may pre-. dominate, and perhaps cause the ship to fall off in the very opposite direction from that which is desired. *
The "reverse effect" of the rudder as described here, is a general result observed in certain classes of vessels under stated conditions. To rely upon that effect under all circumstances would therefore be as unreasonable as to attempt to tack ship by the same means, whether under double-reefed topsails in a seaway, or under plain sail to royals in smooth water. Details of absolute accuracy for even one type of vessel under varying conditions of wind and weather have yet to be recorded.
Avoiding Dangers. With a right-handed screw great caution should be observed in stopping and backing, to avoid immediate danger ahead and to starboard. When
* The auxiliary steering screw described in the latter part of this chapter is claimed to reduce this "danger interval" to a minimum.
the engine begins to back the bow tends to fall off to starboard, and the helm put hard aport may not counteract this tendency in time to clear the danger. Of course when moving astern with sufficient speed the helm should overcome the screw effect, but that may be too late.
If the way is open to port, a quick starboard helm, slowing down if necessary, might be more apt to carry you clear.
Were the danger ahead and to port, by porting, reversing the engine to full speed astern, and quickly shifting the helm to hard a starboard by the time the engine begins to back, screw and helm would combine in their action to carry the ship's head to starboard, and would probably do so sufficiently to avoid the danger.
In passing dangerously close by another ship or other obstacle, remember that when the helm is put over to prevent collision, it is the stern that moves, and that while the bow may be thus saved from touching, the stern may be fouled; but that if the helm be quickly shifted when the bow is just clear, the stern will be thrown out. Many a "touch-and-go shave" has been thus effected by judgment and nerve. This is a good practical hint, and one worth remembering.
Effect of the Wind and Sea on Steamers. The bow of a screw steamer having no headway, will fall off from the wind. If on an even keel, and the exposed surface is about equal fore and aft, she will lie with the wind abeam. If by the stern she will bring the wind abaft the beam.
If the engines of a screw steamer be reversed when head to wind she will in a short time turn stern to it.
If the engines of a screw steamer be reversed when in the trough of a sea she will, sooner or later, bring her stern to the sea.
Stopping. The distance required by a screw steamer to bring herself to a standstill from full speed, by the reversal of her screw, is said to be between four and six times the vessel's length. The same authority * states that this distance is independent of the power of the vessel's engines, or nearly so, depending upon the size and build of the ship. The statement is probably incomplete. Given two sister ships cruising in company at the full speed of the slowest ship; one vessel having very much better engines than the other, and able to steam several knots faster. If both suddenly reverse and back at their utmost speed, it would seem that the ship which can move the fastest astern will come to a stand sooner than the other.
Casting under Steam. An officer knowing
* Report of Professor Osborne Reynolds and the Committee of the British Association "To investigate the effects of propellers on the steering of vessels."
which way his ship tends to turn in backing, takes advantage of that knowledge in paying around to cast, if circumstances permit him to choose the direction of the turn to be made.
To turn in a limited space, put the helm hard a starboard and back on the engine, then hard a port and go ahead, repeating the operation until the turn is completed, as shown in the figure. The bow will swing to starboard, both when going ahead and astern.
It would be very difficult under the above conditions to make the turn to the left without the help of sails or dropping an anchor under foot, for the angle gained while going ahead would be, at least partially, lost in backing.
STEAM AND SAIL.*
When a steamer goes ahead fast, the vanes are very deceptive, the wind appearing more ahead than it really is. When in doubt, set the flying-jib as a "wind feeler," steady aft the trysail sheet or haul out the spanker. Should the latter stand well give the order-
Clear away the fore-and-aft sails!
Man the sheets and halliards! and when all ready, Haul taut! HOIST AWAY! HAUL AFT! Hoist the jibs taut up and trim down the sheets. Hoist the staysails and trim aft
* One effect of the combination of sail with steam power in propelling a ship, is to increase the efficiency of the screw; for as it then has a part, instead of the whole of the resistance of the water to overcome its slip is diminished.--RANKINE.
the trysail sheets. Care must be taken that the main-topmast-staysail does not catch fire from the smoke stack. Should the wind draw aft you may try the foresail, and if that stands well, get all the canvas on her that will draw to advantage, excepting the mainsail, which, on account of the smoke stack, remains furled, with its cover on, or is unbent.
NOTE.-When making sail on a steamer, the senior engineer should be duly informed with regard to the engine, that he may haul the fires, or bank them, as occasion requires. Heavy banks are such that the fires may be spread and steam got up in a little while; light banks require more time to get ready.
To Tack a Steamer. Under canvas and steam, should it be required to tack ship, proceed as if under sail alone; if going very fast, slow down before luffing around, otherwise the sails as they fetch aback may bring too great a strain on the fore-and-aft stays. When you "let go and haul," ring to go ahead fast.
To Reduce Sail. If ordered to furl sail and proceed under steam, send down to the engineer to get up steam,* raise the smoke stack and lower the propeller, haul up and furl the mainsail, and put the cover on or unbend it. Fill the fire-buckets aloft. When steam is up, call, SHORTEN SAIL! take in and furl everything, put the covers on and ring to go ahead.
When under steam be particularly cautious not to allow ropes to tow overboard, and in heaving the lead, care must be taken that the line does not foul the propeller. Send the light yards on deck, point the other yards to the wind or brace them sharp up. The topsail yards will soon take against the lee rigging, therefore sway them up about one-third and clap jiggers on the lifts; haul all the rigging taut.
To Make Sail on a Steamer. If ordered to let the steam go down and make sail, send the necessary directions to the engineer, and set all the drawing sail, including the mainsail, as soon as the smoke stack is out of the way.
Weather Helm. A screw ship under canvas is said to carry more weather helm than a sailing vessel, because the water passes along aft, on the lee side, and finding the screw aperture, passes through it; and thus offering less resistance permits the after part of the vessel to sag to leeward, and the forward part to approach the wind, a tendency which the weather helm is called upon to check; furthermore, it is not only the water which actually impinges upon the rudder which turns the ship; the check received by the water from the rudder is communicated to the water before
* Or ring two bells to "spread fires."
it for some distance, and this effect is entirely lost with the narrow stern-post of the screw.
DIFFICULTY OF TACKING A SCREW-SHIP UNDER SAIL.
In tacking, as long as a sailing ship has headway, the water coming along the weather side of the bottom strikes the rudder and assists to turn the ship; but, in a vessel with a screw aperture, the water meets a constant current coming from the lee side through the screw hole caused by the lee way the ship is making, and the side movement of the stern, and is consequently carried off with it at a considerable angle from the line of keel without touching the rudder at all.
In tacking steamers under sail alone, in addition to checking head braces, flowing head sheets, or even hauling down head sails, it is a very common practice to brace around the crossjack yards when the vessel is within a point or two of the wind, before hauling the main yard. The object is to throw the stern in the direction to be taken in paying off on the new tack, and thereby bring the wind on the (new) weather bow. Such counterbracing is of course adopted only when it is taken for granted that the vessel cannot be brought around without a sternboard.
EMERGENCY SIGNAL TO ENGINE-ROOM.
As a rule, when steaming ahead at full speed the signal made to the engine-room, when it is desired to stop the engine, is first to "slow" (one bell), and then to "stop" (two bells).
Similarly when the engine is reversed, to go ahead the signal will be first made to stop (two bells) followed by one bell to go ahead.
In case of an accident, however, the required final signal is made at once, without intermediate signals, and as this should never be done excepting under such circumstances, the very fact of making "stop" from "full speed" constitutes a signal of emergency and it should be obeyed with the least possible delay.
Man Overboard. Under steam. Stop and back. Lower boat when in best position to rescue man.
Under steam and sail. Hard down the helm. Stop and back. Take in light sails if necessary, trim yards to assist in backing towards the man; lower boat in best position for rescue.
In both cases, observe the usual precautions about lowering a boat when making sternway.
Heaving to for Sounding, under steam. In moderate depths, slow down or heave to, either head or stern to, as convenient. In great depths, stern to. For description of sounding apparatus supplied for use with reeled piano wire, see Appendix M.
Handling Vessel under Steam and Sail in Squalls. Luff and shake her, or, if too heavy, hard up, brail up spanker, and put her before it, going ahead at full speed,-the steam power in this case enabling the vessel to pay off with the desired rapidity.
Bad Weather under Steam. If in a steamer of sufficient power, heave to head to sea with no sail set, using a sea anchor if desirable. Some steamers, notably long merchant steamers of recent construction, heave to with the wind on the quarter, engines going ahead slowly. But it would be unsafe, probably, for shorter steamers to do so.
A full powered steamer should be able to run before any sea.
Steamers hove to under sail alone, will vary greatly as to the amount of canvas spread and its disposition, but the conditions to be fulfilled are usually the same in all cases, viz.:
First, To show enough canvas, if possible, to ensure steerage way.
Second, To dispose it so as to counteract too great a tendency to fall off.
Modern steamers are often undersparred, so. that any one sail is comparatively small when the immersed longitudinal section is considered. Moreover, the steamer has greater proportionate length than the old fashioned sailing vessel, and a greater tendency to fall off.
The inference is that steamers will heave to under canvas with a greater number of sails and with more after sail than a sailing vessel of older model.
Hence we find many steam men-of-war heaving to under close reefed main topsail, main trysail, and storm mizzen or reefed spanker; the fore storm staysail being bent, but not always set. Others will hold on to the close reefed fore topsail as long as possible, in addition to the above canvas, to ensure the necessary steerage way.
Sending down the light yards and masts, whether under steam or sail, will greatly relieve the ship in heavy weather.
TAKING IN TOW AT SEA.
(a) There is a fresh breeze blowing, and A is wholly disabled, or nearly so. B steams along the weather side and throws a heaving line, if prudent, then puts helm hard a starboard, and stops when she can maintain her position
on the bow of A, for some little time. If it be desirable to send a boat with a heaving line she is in a good position for doing so.
(b) It is blowing a moderate gale. A is totally disabled, and in the trough of the sea. B dare not lower a boat, but slings a water-tight empty cask to the end of the deep sea lead line. She steams up on A's weather quarter at a safe distance, veering or hauling in line to bring the cask alongside of A. B then puts his helm hard a starboard, and holds his position till the towline is fast on board of A.
(c) There is a heavy sea, and A is under control. B
steams ahead at a safe distance, head to wind. A barrel, full of holes, is slung, and the rope paid out until alongside of A. The barrel being full of holes will sink to the water's edge and will not be affected by the wind. A cork fender and grate bar may be used instead of the barrel.
(d) Calm and smooth sea. A is disabled. B steams along her port side and throws a heaving line, puts helm hard a starboard, stops and hauls hawser on board.
(e) In a seaway. A has rudder disabled, but motive power is good. B wishes to help her into port. B takes hawsers from A's quarters. A tows
and B steers. By this disposition, both steamers being large full powered vessels, B can steam at least at half speed, thus relieving A of that much work. If A were being towed, she would take rank sheers at short intervals, obliging B to slow
or stop to prevent parting towlines. Moreover, if B were to tow, A could not use her engines.
If A is a small low powered vessel and B much larger and more powerful, B might tow A with short towlines from both quarters.
Chasing. The chaser will steer a course slightly converging to that steered by the chase; taking the bearing by compass and measuring the angle subtended by the masts. By constantly keeping the chase on the same compass bearing, the chaser will attain the chase in the shortest time possible, and by the shortest route.
If the course steered by the chase is more advantageous than that steered by the chaser, the latter can steer a parallel course to take the same advantage, until he arrives as near as possible (that is, abreast of him), and then steer a course to cut him off. Make sail when it will draw.
The vessel chased should employ every means to retard the time of being overtaken. A few cables' lengths more may suffice to save the chase; because a fog, an injury to the chaser, or night coming on, may enable him to escape.
Should the chaser be a sailing vessel, the chase will steam directly to windward. *
Collision. On a collision in steaming, upright the screw. In that case gear dragging overboard will not foul it, otherwise it will.
On a collision taking place when on soundings, it is generally best for the weathermost ship to anchor.
When two ships are becalmed near each other, either send the boats of both to tow the lighter, or of the one that lies in the most favorable position (with reference to swell) for being moved; or else, run warps out from the quarter of one to the bow of the other, or vice versa, and both may thus be sprung ahead and steered clear of each other.
To Anchor a Steamer. Ordinarily this is accomplished as follows: Steam in, "slow down" in good time, and, when near the berth determined on, stop the engine; as soon as headway ceases, and she commences going astern, let go the anchor and veer to the proper scope. With an ebb tide, anchor "head on," and the tide will carry the vessel astern fast enough to take her chain. If a flood tide, the vessel should be sheered with the helm, and the anchor dropped so that she may not overrun her chain. When there is not enough wind or tide, reverse the engines, let go the anchor, and back till the required scope is laid out straight.
"Fifteen or twenty minutes before coming to anchor, the chief engineer should be informed of the fact, so that the fires can be allowed to burn down, and the pressure of steam to fall to such an extent that the necessity of blowing
* For Ship's Papers, see Appendix N.
off is avoided. By this means the great nuisance of blowing off steam is not only obviated, but there is a considerable saving of fuel, the fires being permitted to burn down sufficiently low to supply only the amount of steam required while working the engines by hand, rendering it much easier also on the firemen (whose duties on any occasion are arduous enough), by having a very light instead of a very heavy fire to haul." *
Due notice should also be given before stopping to sound, or stopping for any purpose whatever. The observance of this rule is quite important.
On entering a narrow channel with the flood tide, a steamer could not "round to," but would have to anchor "end on," and swing to the tide; but if waiting for high water, intending to pursue her way up, she would have to anchor by the stern to keep pointed fair.
If after entering a narrow channel a steamer should find herself compelled, by the discovery of heavy batteries, or the appearance of the enemy in superior force, to go out again, the quickest way to wind the vessel would be by dropping and swinging to an anchor; then, as soon as pointed, heave up or slip, making all preparation beforehand.
Should the ebb tide be running, make use of a kedge, and anchor by the stern, giving the vessel a sheer with the helm, that the tide may catch her on the bow and sweep her around. On the flood, let the kedge go from forward to wind her, availing yourself of the helm, jib, spanker, and engine, as circumstances admit.
When ascending rivers where the turns are short, the engine should be slowed down," or stopped, just before coming to a bend, to prevent reaching over to the further shore; and when going up against a strong ebb tide, in such a river, for example, as the Piscataqua, N. H., the engine must be stopped, and should that prove insufficient, an anchor must be let go in the bend to permit the vessel's head to swing to the new course. When pointed right, weigh and stand on. This is an extreme case, however.
Young officers are liable to forget the great use of the jib and spanker in turning a steamer; they are often indispensable.
Mooring to a Buoy. Steam up to moorings slowly, keeping steerage way. If there is no wind, keep the buoy a little on the starboard bow, and when the engines are reversed the bow will fall off, bringing the buoy ahead. ** If the wind is on the port side, the buoy should be brought more off the starboard bow, as she will swing off more rapidly when the engines are reversed.
* Practical Notes on the Steam Engine, by J. W. King, Chief Engineer, U. S. N.
** References are exclusively to right-handed screws.
If the wind is on the starboard side, steam directly for the buoy, if the force of the wind will balance the tendency of the bow to fall off to starboard when the engines are reversed.
If obliged to moor with fair tide or wind directly aft, great care should be taken not to overrun the buoy. A boat should be lowered to carry the warp when the engines are reversed. Do not lower the boat too soon or she may be left astern. For the detail of handling the chain see page 253.
In approaching moorings from to leeward, and with wind and tide so strong as to make it difficult for the boat to pull to windward with a whole warp aboard, the boat may be lowered in good season and given time to reach the buoy. Boat to carry a short towline and a heaving line. Having secured one end of the warp to the buoy and bent the heaving line to the other end, the boat awaits the arrival of the steamer, and at the proper moment pulls for her, tossing the heaving line when within range.
Large steamers frequently find it very difficult to get clear of their moorings in a crowded harbor. When the wind serves, the jib will be of great assistance; otherwise, the slip rope may be veered out as far as practicable and a broad sheer given with the helm or propeller.
The slip rope should be rove from forward aft, and the end secured well abaft the hauling part, so that when cast off it will fall clear. A steamer's bow may be brought back to the buoy under very embarrassing circumstances by the end of the slip rope overriding the hauling part.
If the vessel overrides the buoy and there is a probability of fouling the propeller, the engine should be stopped at once. There will be a possibility of its going clear, and if not, there will be a fair chance of no damage resulting. If the vessel is head to tide, or wind, there is still a chance of clearing when she gets a sternboard in the act of swinging. If this fails, a strong hawser from the bow made fast to the buoy and taken to the capstan would probably clear it, particularly if there were not much tide.
Mooring at a Wharf: To make a successful landing at a wharf it is necessary to know the action of the tide or current. If by chance there should be neither tide, current, nor wind, it becomes a comparatively simple matter.
To moor at a wharf, slack water and calm. There is an advantage in approaching a wharf on the port hand, for if the bow should be pointing too much for the wharf a few turns back on the engine would swing her off, whereas were it on the starboard side the bow would be carried still more towards it. As soon as the wharf is approached, heaving lines are thrown ashore and bow and stern lines run to piles. If the vessel does not come up to the wharf promptly, make the stern line fast and give the engines a turn ahead, taking
in the slack of the bow line. Then back and take in the stern line.
If it is a smooth water berth and clear gangways are desirable, the bow and stern lines may be used as springs and breast lines passed out as shown in the figure.
A wharf should be approached with a head tide when practicable. The bow fast would then be run out and the vessel dropped alongside. If the tide be weak a turn of the screw will assist. The stern fast and springs may then be passed out.
If there be a fair tide, the stern fast should be got out first and a turn taken, when the vessel will drop alongside.
If there be an eddy setting in the opposite direction to the current it must be allowed for.
The most dangerous eddy is one setting directly toward the wharf. In this case as little drift as practicable should be allowed, as there is danger of bringing up with great force against the wharf.
The most vexatious eddy is that which sets directly out from the wharf. In this case the vessel must reach her position under good headway, the engines be reversed promptly and headway stopped. The fasts must be gotten out as quickly as possible, and the vessel gradually sprung alongside by going ahead and astern alternately and taking in the slack of lines.
When the propeller cannot be worked it is frequently the custom to veer the bow fast well out and haul the stern to the wharf, the bow fast is then hove in by the capstan or windlass and the bow brought to the wharf. It is easiest to get the ship alongside in this way, there being less resistance (owing to the lesser draft) forward, and the capstan is handy for heaving the bow in.
To moor at an exposed wharf, where there is a heavy swell, making it unsafe to lie alongside. In such cases mooring buoys are commonly placed in position broad off the wharf. Run in between the buoys a n d the wharf, and run one
warp from the bows to the wharf and one to the corresponding buoy. Hold the vessel in position by means of these and the propeller, and run other fasts. The springs should be double, and run at about equal angles. It will be seen that if the vessel surges on or off ahead or astern she will bring an equal strain on springs and bow and stern fasts.
Hauling in to a wharf from moorings in the stream. A vessel riding to moorings in the stream and wishing to haul alongside the wharf would run a bow warp ashore and make another fast to the mooring buoy. Veer on the latter and walk away with the shore warp. Keep the tide ahead or on the offshore bow by means of the helm. The stern fast should not be run out until near the wharf, and should not be hauled in until the bow is in position, providing there be tide enough to keep her pointed.
Men-of-war having been hauled alongside a Navy Yard wharf generally use the fixed moorings prepared for the berth at which they lie, as shown in the figure.
The offshore cable A is taken in through the offshore sheet hawse pipe.
The offshore quarter mooring B is taken to the mooring shackle under the mizzen chains; C and D, the inshore moorings, are similarly secured. There may be also additional breast fasts, as at E and F.
The ship is kept clear of the wharf, which is the side on which the moorings are usually the tautest, by means of spur shores as in the figure. These consist of heavy spars, the inshore end supported on trucks. The outboard end is made to bear against the ship's side by a chain passing through a score in the heel of the shore, or better through the shore itself between the ship and the trucks, so that the chain will not foul the latter. The ends of the chain are secured to piles; a tackle may be clapped on one end of the chain.
The outboard end of the spur shore should take upon a saucer hung from the ship's side. This outer end should
have a bolt on top for a tackle, to hang the shore if the ship is forced from the wharf; also used to haul the spur shore into position.
Hauling into a Dry Dock. The ship at
A has her bow warp run to the head of the dock and
forward breast lines fast to piles. A tug has a line to A's port quarter and is in the act of pointing her. This is done at or near slack water.
At B the ship is nearly in the dock. Her bow warp, with which she is hauling in, is fast to a pile at the head of the dock.
Forward and after breast lines or check lines are fast to piles. The vessel is kept in position by slacking these check lines from time to time. They are passed up the dock from pile to pile as the vessel advances.
Backing a Vessel into a Slip. Steamboat men acquire great skill in handling their boats about
wharves, by availing themselves of the properties of the spring and the power of the engines. Let A represent a fixed point. By
steaming ahead it is evident that the line AB will spring the ship's head around in the direction of the dotted line.
In the same manner, by backing, will AB1 spring her stern around the point A as a centre.
Again, let it be required to back a steamer into a narrow slip. By the use of a quarter spring on starboard quarter, and backing the engines, the ship may be made to turn on her centre as in the above cut. A line from the starboard bow carefully tended prevents her from swinging off too much.
Should it be required to get the ship A to the wharf at B, back the engine, when the starboard bow line will bring the
ship alongside the wharf, and by checking the line handsomely, she may be brought to the berth required.
Taking a, Vessel in Tow, in Port. Tugs when towing in strong tideways or crowded harbors always make fast alongside the tow, and usually as far aft as possible.
Before the tug comes alongside, make preparations on board the tow by getting out fenders, unshipping gangway ladders, tending braces, running in guns, and topping up boats as may be necessary. Have hands stationed to receive the heaving lines.
The lines used by the tug are the towline proper, or spring, from the bow of the tug to the quarter of the tow; the bow line, from the bow of the tug to a point well forward on the tow; also two breast fasts from the bow and quarter of the tug to points directly abreast on the tow. In backing, the bow line has a good lead to give the necessary sternboard to the tow. In giving a rank sheer with the helm, the bow, or quarter, breast fast (as the case may be) will keep the tug in position and prevent her sheering away from the tow.
If the screw of the tug is right-handed, she will make fast to the port side of the tow, circumstances permitting.
In this position the tug will make a much straighter sternboard if obliged to back, and in going ahead under port helm (the weak helm) she will control the tow more effectually than if on the starboard side.
In towing a vessel of the Trenton class in the East River a tug of the Catalpa size (200 tons) would use an 8-inch spring, 8-inch bow line, and 6-inch breast fasts. The same tug, towing the Galena, would not need larger lines than 6-inch for spring and bow line.
The method of towing alongside is not used at sea, unless in very smooth water. In attacks on fortified places it has been used to great advantage.
If it is desired to tow from ahead, the tow having been notified, will send her hauling lines aboard when you have taken up a position ahead. Steamers have bitts to make fast their tow ropes. The vessel towed will take them either to the bitts or capstan.
In taking a vessel in tow from an anchorage, the towing steamer may be forced to anchor ahead of the ship to be towed, and the latter will first heave up (the hawsers being secured), and then the towing steamer.
The latter when ahead should use a bridle. The bridle lessens sheering, which might result in carrying away the dolphin striker or head stays.
THE TURNING POWERS OF SHIPS.*
In a calm and in smooth water when a steamer is advancing on a straight course, with uniform speed, the action of a very small disturbing force will deflect her from that course. As soon as the helm is put over and an unbalanced pressure is developed on the rudder the vessel begins to turn.
Her angular motion is gradually accelerated as the helm angle is increased, and after the helm is hard over. After reaching its maximum the angular motion becomes uniform, and thereafter if the helm and revolutions of the engines remain unaltered the vessel continues to swing around through equal angles in equal times. Where there is powerful mechanical steering gear this condition of uniform
circular motion is quickly reached, probably by the time a ship has swung through 360° or even a less angle from the original course.
With manual power at the helm, similar uniformity of angular motion is not obtained until the ship has completed two or more circuits, the longer time in putting the helm over accounting for the difference.
The curve traversed by a steamer in making a complete turn of 360° brings her somewhere within the true circle by a distance varying (other conditions being equal) with the amount of time required in putting the helm over.
In Fig. 1 the vessel has started to turn at P
* From "Lecture on the Turning Powers of Ships," by W. H. White, R. N., and the discussion by Capt. Colomb, R. N., and others of the said lecture. Reprinted from the Journal of the Royal United Service Institution in Navy Scientific Papers, No. 7.
PE is defined as the tactical diameter, or the distance between the two positions when the original course is reversed.
At C, when a curve of 90° has been described, of which PG and GC are the coordinates:
GC is the advance, or distance that the ship has moved in the direction of her original course.
PG is the transfer, or distance that the ship has moved in the direction due to the position of the helm.
Then, if O is the centre of the final circle, FD is the final diameter.
These are the elements of the curve so far as space is concerned, and what should be known for every ship is the advance, and the transfer up to 90° and the tactical diameter. The elements of time required are the time which it takes the ship to go from P to C, and to pass from C to D, and consequently the time from P to D.
The determination of the tactical diameter corresponding to various revolutions of the screw and various helm angles for individual ships is also of value. This is especially true where vessels of different sizes and types are assembled for combined movements under steam. In such a squadron, each vessel must know by experiment the number of revolutions which will give the same speed as a given number of revolutions of the flagship's screw. In like manner, each ship must know the value of her helm angles, relative to the helm angles of the flagship, and of other vessels of the squadron.
Drift Angle. Fig. 1 assumes that when the centre of gravity of a ship has turned through a path of 90°, the line of keel has also altered 90° in direction. But as a matter of fact the centre of gravity will have turned 90° some time before it reaches C.
The drift angle, which represents this difference, is the angle between a tangent to the path of the ship's centre of gravity and the keel line.
As the ship commences her turn, the drift angle will be an increasing quantity until uniform motion is reached.
In Fig. 2 the motion of rotation is assumed to have become uniform. The centre of gravity is then moving in a circle, and the keel line of the ship will make a constant angle with the tangent to that circle.
A represents the bow and B the stern of the ship. C shows the position of the centre of gravity on the keel line AB. O is the centre of the circular path in which C, A and B are moving. T T1 is the tangent to the path (G1, C, G2)
of the centre of gravity and the angle ACT is the drift angle.
The value of the drift angle varies considerably in different vessels and in the same vessel under different conditions of speed and helm angle. In the Thunderer, for example, with a constant helm angle but with varied speed, the angle was as follows:
|DIAMETERS OF CIRCLES (FEET).
The drift angle increases:
(a.) With increase in speed when the helm angle and rudder area are constant.
(b.) With rudder area and helm angle, speed being constant.
In any given time the head of the ship must have turned through an angle from the original course which exceeds the angle turned through by the centre of gravity, by a quantity equal to the drift angle.
In Fig. 2, if P is the foot of a perpendicular from the centre 0 upon the middle line of the ship A B, then to an observer on board, P will appear to be the "pivot point" about which the angular motion of the ship is being performed; for the keel line A B coincides with the tangent to the path of the point P, which is not true of any other point on the keel line. Hence, at P, there is no drift angle.
In the case of the Thunderer, the pivot point P varied from 67 to 103 feet before the centre of gravity, or from 80 to 40 feet from the stern. As the speed and drift angle increased the pivot point moved forward.
To the drift angle is due the loss of speed sustained by a ship in turning. In several cases where this loss has been carefully measured, the speed of advance on the circular path has been only seven or eight tenths of the speed on the straight. The drag of the rudder has little to do with this loss of speed.
Glancing once more at Fig. 2, it will be evident that at each instant while the propelling force is delivered along or parallel to the keel line the actual motion of the vessel in turning is not directly ahead, but sideways.
In fact, the motion bears a considerable resemblance to that of a vessel sailing on a wind, and there is a considerable pressure developed on the side of the bow most distant
from the centre O. This pressure not only checks the speed of the ship, but exercises a decided turning effect, assisting the pressure on the rudder. The importance of this assistance will appear more clearly when it is remembered that owing to the rotary motion of the vessel while turning, the flow of water at the stern is different, even in screw steamers, from that which would take place before the angular motion became marked. In fact, the effective helm angle becomes very much reduced from the angle RBD, Fig. 2, which the rudder makes with the keel line AB, produced. We have no exact data for estimating the amount of this reduction, but it approaches to equality with the drift angle for the rudder axis B. If OB is joined, and BQ drawn perpendicular to it, then the effective helm angle, according to this rule, should be taken as approximately equal to RBQ, and not to DBR, or a reduction of at least one-half from the angle made with the keel line, even in single-screw ships. Approximately the pressure on the rudder may be expressed as a function of the speed of the ship, and the sine of the effective angle of helm; so that the loss of rudder pressure consequent upon such a reduction in the effective angle as is asserted to take place will be very considerable. Apart from exact measures of the reduction, there can be no question as to the fact; and it is one of the matters upon which further experiments might well be made. With the assistance of a dynamometer to register the strains on the tiller end when the helm is first put over, and after the turning motion has become uniform, it would be an easy matter to discover the variations in the effective helm angle if the revolutions of the engines and speed of the ship were also observed.
Heeling. The amount of heeling which accompanies turning is credited generally to the rudder pressure, whereas that effect may in most cases be neglected in comparison with the centrifugal force.
A fair approximation to the angle of heel for a ship in turning is given by the following equation:
sin θ = 1/32 x d/m x v2/R
θ = angle of heel,
v = speed of ship in feet per second,
R = radius of circle turned (in feet),
m "metacentric height"-height of transverse metacentric above centre of gravity,
d distance of centre of gravity above centre of lateral resistance.
In the Thunderer, the centre of lateral resistance was found to be from .43 to .49 of the mean draught below the water line; probably a fair approximation for war ships of
ordinary form would be from .45 to .5 of the mean draught. From the foregoing equation it will be seen that-
The angle of heel varies:
(1) Directly as the square of the speed of ship;
(2) Inversely with the metacentric height;
(3) Inversely with the radius of the circle.
Hence it is obvious that ships of high speed, fitted with steam steering gear, capable of turning on circles of comparatively small diameter, are those in which heeling may be expected to be greatest. Moderate values of the meta-centric height further tend to increase the heeling. If the speed be doubled, the angle of heel will be about quadrupled, if the radius of the circle turned and the metacentric height remain constant.
It is important to notice, that in taking observations of the angle of heel for a ship in turning, allowance must be made for the effect of the centrifugal force upon the indications of pendulums or clinometers. The error of indication is always in excess, and the correction is very easily made when the diameter of the circle and time of turning have been ascertained.
As the guns of a ship may be laid for simultaneous firing by director when the ship is on a straight course and on an even keel, and fired when the ship is under the influence of her helm, it may be of considerable importance to know what heel is to be expected for a given speed and_ helm angle, to adjust the director and lay the guns accordingly.
Helm Angles. Other things being equal, the rapidity with which a ship turns increases as the time of putting the helm over is diminished, and the diameter of the circle is also influenced. In the case of a British ship, where other conditions were almost unchanged, a steam steering gear was fitted, and the time in putting the helm hard over reduced from ninety seconds to twenty seconds. The time occupied in turning the circle was reduced from eight and one-half minutes to a little over seven minutes, and the diameter of the circle was reduced from 970 yards to 885 yards.
Before steam steering gear became common, equipoise rudders furnished the best means of putting a large rudder area over quickly to a great angle. But now that mechanical appliances are available, ordinary rudders hung at their forward edge are once more preferable, because they are less liable to derangement and more suitable for use in ships having sail as well as steam power,
Other things being equal, the turning effect of a rudder increases with an increase in the helm angle up to 40° or 45° with the keel line.
As illustrating the latter point, Admiral Sir Cowper Key found that the "Delight" gunboat behaved as recorded
in the following table when the helm angle alone was varied:
||TIME OF TURNING
Lieutenant Coumes, of the French navy, gives the following results for the ironclad corvette Victorieuse, for an initial speed of about twelve and one-half knots:
||TIME OF TURNING
Commander E. M. Shepard, of the U.S.S. Enterprise, reported the following for an initial speed of eight knots, being two-thirds power:
||TIME OF TURNING
Tactical and Final Diameters. At present the published information of the ratio of tactical to final diameters is very limited, but for all practical purposes the determination of tactical diameters is the more important.
With manual power and ordinary rudders the tactical diameter for large ships has been found to vary between six and eight times the length of the ships.
For small vessels, where manual power suffices to put the helm over rapidly and the speed is low, the diameter falls to three or five times the length. For very long and swift torpedo boats, with manual power and small angles of helm, the diameter for full speed is as much as twelve times the length, and for half speed about four to six times the
length. With manual power and balanced rudders the diameter for large ships has been reduced to four or five times the length; and nearly equal results have been obtained with ordinary rudders worked by steam or hydraulic steering gear. About three times the length is the minimum diameter ever obtained in large ships turning under the action of their rudders.*
Effect of Twin Screws. Twin screws are now frequently adopted in the most powerful war ships, and their efficiency as propellers recognized. But they have the further advantage of enabling a vessel, by reversing one of her screws while the other drives her ahead, to turn in a very small circle, almost in her own length. The rate of turning is often slow under these circumstances, but the power of giving rotation to a ship practically destitute of headway and with a rudder possibly disabled, is of great value.
With regard to the turning effect of twin screws when working in opposite directions, in deep-draft ships the time occupied in turning is usually greater than the time for turning the circle with both screws working ahead at full speed; whereas for shallow-draft ships the corresponding difference in time is small. For example, in the Captain, the time for circle at full speed ahead was five minutes twenty-four seconds; that for circle with screws working in opposite directions, six minutes fifty-two seconds. In the shallow-draft gunboats of the Medina class, on the other hand, the full-speed turning trial gave about three minutes six seconds for the circle, and with screws working in opposite directions the time was only three minutes thirteen seconds. It will be obvious that in the shallow-draft ships the ratio of the moment of resistance to rotation to the turning moment of the screws is much less than the corresponding ratio for deep-draft ships.
With ordinary rudders the use of twin screws does not appear to interfere with the efficient action of the rudder when both screws are working ahead, as compared with that in single-screw ships; experience has shown that equipoise rudders are not desirable features in twin-screw ships. With steam or mechanical steering gear the use of equipoise rudders is, on other grounds, not preferable; so that this feature in the use of twin screws is of comparatively small importance.
Exercises under Steam. Steering trials made during the service of a ship at sea enable officers to gauge the effective performance of their vessels under varied conditions of wind and weather, speed and helm angle. The
* The methods suggested for measuring the diameters of circles will be found in Appendix L, together with the results obtained for the "Tennessee," "Quinnebaug," and "Enterprise."
value of such knowledge cannot be over-estimated. On the subject of turning trials an eminent authority * is quoted as saying that a table of turning powers is no less necessary to a ram than a range table to a gun. But exercises in manoeuvering should not be confined to the describing of circles and determining of tactical diameters. In the Mediterranean squadron under Lord Clarence Paget, R. N., the vessels were exercised on convenient occasions in performing a figure of 8 evolution. This was done by placing buoys as shown in the diagram, and under the following conditions, viz.:
A, B, C, D, are four buoys placed in the form of a parallelogram, of which the long side will be approximately four and one-half times, and the short side three times, the length of the ship.
E, F are two buoys placed one length and a half of the ship apart, and at even distances from the centre of the parallelogram. The ship is to enter the parallelogram, either between B and D or between A and C, the exact time of her stern passing the dotted line between the two buoys being noted; she is then to perform a figure of 8 within the parallelogram by crossing, each time between the points E and F, as shown in the diagram, and she will then come out at the opposite end of the parallelogram from that at which she entered, the precise moment of her stern passing between the buoys on leaving the parallelogram being also noted.
No ship is to use more than half-boiler power, but she may aid herself in any manner by the use of sails or otherwise, as may be deemed expedient.
When once the ship is within the parallelogram, if any part of her should touch the dotted straight lines between the buoys, she will be supposed to have grounded, or should she touch either of the buoys E, F, she will be supposed to have fouled the ships which they are intended to represent. In either of these cases the manoeuvre must be presumed to have failed. The direction and force of the wind, the state of the sea, and the direction and strength of the current (if any) are to be noted during the experiment.
* Captain (now Admiral) Bourgois, French navy
As to the results, the author of the pamphlet from which this description is taken,* states the following:
"This exercise had the effect of teaching the officers what were the steering capabilities of their ships, not only whilst going ahead, but when moving astern; and I may add that after we had made the experiment twice, in which I am bound to say we did not quite succeed, I had much greater confidence in managing the vessel when moving in or out of confined harbors, or in close order with the squadron. Such practice as this must prove useful, and cannot fail to instil valuable instruction regarding the steering properties of a vessel, not only for the benefit of her commander, but also of the lieutenants and master."
One may be enabled, by practice of this kind, to tell, within a few yards, where any ordinary combination of tide, wind, and rudder will place the vessel. With readiness of resource and good judgment, an officer applying such knowledge in action is likely to prove a dangerous antagonist.
STEAM STEERING GEAR.
The importance of the use of steam as a motor for steering ships was recognized many years ago. At that time practical men noticed the idea only with derision, but of late years its application has been common in the merchant marine and in foreign navies. Its introduction on board our cruisers is recent. One form adopted in the service is that invented by Mr. Sickels, the designer also of the "Trenton" windlass, previously described.
Plate 124 shows the general form of the Sickels' steam steering; the particular design being that adopted for the U.S.S. "Lancaster."
The engines AA consist of two cylinders of the half trunk variety, placed at an angle of 90° to each other and acting on the same crank pin; the shaft is above the cylinders, and the frames are cast on.
The valves are of the kind known as piston valves, steam being admitted in the middle and exhausted at the ends and through the valves. These valves are made with excessive lap on the steam side, and have a triangular score cut in them, by which means steam is admitted, at first, the object being to avoid the jerking motion which would result from a sudden, free admission.
There is also a negative lap on the exhaust side for the purpose of readily freeing the cylinders of water.
Upon one end of the crank shaft is secured a deeply grooved conical drum D, for the reception of the tiller ropes.
* Admiral E. A. Inglefield, R. N. "Recent Experimental Cruising," &c.
This drum is so constructed that when the helm is hard over the relative leverage is double or treble that when it is amidships, thus increasing the leverage where the resistance is greatest. The cone is also so proportioned as to get the same effect, as regards uniform tightness of ropes, as a quadrant or sliding block on the tiller would give.
On the opposite end of the shaft is a brake wheel, W, secured by a key and set screw.
The brake is a wrought iron hoop which embraces three-fourths of the circumference of this brake wheel; it is lined with a strip of red cedar and is held in place by adjustable springs in the brake fastenings, S, S. The use of this brake is to steady the operation of the machine.
In the brake wheel on the side farthest from the drum is inserted a pin fitting snugly, but free to move, and held in place by a key on the opposite side. This pin is forged on an arm, at the other end of which is forged another pin, to which are connected the valve stems. The last pin has a cam yoke, the yoke, pins, and arm being in one forging.
When the valves of the engine are in a neutral position, the pin on the arm, which operates them, has its centre coincident with that of the crank shaft.,
In the same centre line as the main shaft is a small shaft, supported in a bearing B; the centre of this bearing is enlarged by a collar on which is cut a thread which operates an indicator I, for the purpose of showing the position of the tiller. On the end of this small shaft nearest to the crank shaft is forged a disk; to the after side of this disk is secured a cam which fits neatly into the cam yoke. The cam is of brass, with steel shod points and sufficient eccentricity to actuate the valves.
The disk has also attached to it a pulley of brass, P, with a grooved thread on it, designed to carry the cord from a similar pulley on the hand wheel, intended for steering, placed on the upper deck, bridge, or elsewhere.
The forward end of this independent shaft has a hand wheel, H, secured to the shaft by a set screw. This gives an apparatus for steering, situated with the engine, &c., entirely below the water line.
To operate the machine the hand wheel is moved in either direction desired, thus changing the position of the cam, which in turn changes that of the yoke and pin on the loose arm, thereby operating the valves and causing the engines to revolve their shaft in the same direction as that given to the hand wheel.
The hand wheel having ceased its motion and being independent of the engines, as soon as the latter move the crank shaft and drum through an equal distance, it has brought both shafts to the same relative positions as at starting, and consequently closed the steam valves. The engine shaft, therefore, follows in direction and moves
through the same angle as the hand wheel shaft, and stopping the motion of the latter, stops that of the former.
The steering wheel for the upper deck is usually a small brass wheel, V, mounted on a frame in such a manner as to be capable of an adjustment vertically of several inches, for the purpose of tightening up the steering cord, which is wound in a suitable groove cut upon its face.
A thread on the shaft, cut with a pitch corresponding to the cord grooves in the pulley, allows the wheel a certain amount of fore-and-aft motion. This furnishes a tell-tale to ascertain the position of the tiller and keeps the steering cord constantly in a vertical position over its hole in the deck, obviating the use of the slot cut for ordinary steering ropes.
When there is no steam on, the steering wheel might be moved so far over as to reverse the position of the cam and make the engine work the tiller, when steam is introduced, in a direction opposite to that intended:
Stops have therefore been provided to prevent the cam from being thrown too far either way. These stops consist of pins on either side working against spiral springs inserted on the sides of the yoke, against which corresponding stops on the cord pulley strike.
Below the cord pulley on the cam shaft, is situated a brass piece sliding on a wrought iron guide, carrying on its upper side a tooth which fits into the grooved thread of the pulley. By this tooth the slide follows the groove until it brings up against a stop held by a heavy steel spring. The object is to prevent the hand wheel being moved beyond the distance necessary to put the helm hard over either way.
Any shocks to the helm resulting from the force of the waves against the rudder, or from striking ice, wreckage, &c., are taken up by the cushion of the steam against the cylinder pistons. Hence, when using this steering gear, there is no possibility of the wheel's taking charge in spite of the helmsmen, as sometimes occurs with the hand apparatus.
This apparatus is at all times ready for use when steam is raised, for, from the peculiar arrangement of the valves it is not necessary to first free the machine from condensed water to prepare it for service as is necessary in an ordinary steam engine.
Steam and hand power steering. An important point with any steam steering apparatus is the ability to connect or disconnect it quickly, so that the use of the ordinary hand wheel may be substituted for the steam steering gear or vice versa. To effect this with the Sickel's patent the wheel ropes are rove off on the bight. Instead of securing the ends to the tiller as usual (Fig. 517), they are passed over sheaves and brought forward to the cone drum on the
steam apparatus (Fig. 518). All that is necessary in wishing to use either method of steering is to lock the other in its midship position, and the ends of the tiller rope on the locked apparatus become the standing parts. This locking is instantly accomplished by pushing a pin K through a hole in the wheel, or a flange, thus securing it to some stationary object sufficiently to prevent its turning. Figs. 517 and 518 show the lead of the wheel ropes from the tiller.
The above described apparatus differs essentially from the forms observed on board foreign vessels. In these the machines work with gears or worm wheels, and instead of acting upon the valves by the hand motion, have them driven by eccentrics as in ordinary engines. A supplemental valve is commonly attached with its ports so arranged that when worked by hand, steam is admitted to the centre or ends of the main valve, according to the direction of the revolution required, an arrangement similar to the reversing valve for the Trenton's windlass. The steerer above described is necessarily quicker in action, and is, moreover, noiseless.
Manton's Steering Apparatus (Plate 125). This machine, as supplied to the Miantonomoh for trial, consists of a pair of horizontal engines working into larger gear. Upon these shafts are worms, running into a gear upon the rudder head, as shown in the figure. The valve motion is similar to that of the foreign machines above referred to.
On board the Miantonomoh the valve stem is attached to a screw actuated by a nut connected to a small grooved pulley. This nut is held horizontally by an attachment to the rudder head. The pulley, can give it a rotary motion, and as it is held from advancing or receding by the tiller attachment, the valve is moved through a distance corresponding to the pitch of the thread. In the pilot house is a larger grooved wheel on the same shaft with an ordinary hand wheel.
To work the machine. By revolving the wheel in the pilot house the pulley at the engine is turned, thereby turning the nut and drawing or thrusting the valve. This gives steam to the engines and they will continue to work till the steam is cut off by the reversing (supplemental) valve being put in its neutral position again by the automatic attachment on rudder head readjusting the nut. On the worm shafts on each end of the worms are rubber buffers, or springs, to relieve the gearing from shock of the sea.
With this form of steering gear the wheel ropes for a hand wheel cannot be left connected with the tiller, for if they were the hand steering wheel would revolve with every stroke of the engines when operating the rudder by steam.
Baird's Steering Apparatus. Plate 126 shows this form of apparatus, of which the inventor, Passed. Assistant Engineer G. W. Baird, U.S.N., has kindly furnished the following description:
"The wheel H is used to steer by hand when coupled to the drum D as shown, but if slipped forward on the line of its axis it disengages from its clutch and sliding upon the square end of the shaft S', engages the steam gear only. When steering by steam, any motion given to the shaft S' is transmitted to the valve V through the intervention of the gears G and g, the shaft t, nut n, and lever L.
The valve V admits steam (or compressed air) to the engine E, which starts the drum in motion through geared wheels; but the drum D, which is prolonged into a threaded shaft S revolving within the nut N moves the lever L in a direction to shut the valve V and stop the engine. The arms of the lever and pitches of the screws are so proportioned as to cause the drum D to complete the same angular movement that has been applied to the wheel and to stop then automatically."
This form of apparatus has advantages in the small number of parts, simplicity and accessibility for repairs.
The Value of Steam Steering Gear. In discussing the turning power of ships, attention has been drawn to the question of time occupied in putting the helm over, as a component of the resistance to quick turning. The time so occupied depends directly upon the efficiency of the steering gear.
On board the monitor Roanoke, with the usual hand gear it took two men two minutes to move the rudder from one extreme position to the other and required 19 turns of the wheel. With the steam steerer one man could easily move the helm from hard a port to hard a starboard in 5 seconds with 3 1/2 revolutions of the wheel.
The power which such a machine must exert to put a rudder over to 40° has been found by trial (Napier's experiments) to be equal in statical moment to the product of the following factors:
Area of rudder in square feet;|
Distance of centre of that area from axis of rotation;
Square of speed of advance of screw in knots;
Power in excess of the demand is of course necessary, the amount depending on the tonnage and the nature of the service, but no possible defect lies in the direction of too much helm power.
An ordinary rudder, moved by hand, might answer for cruising purposes, and yet be insufficient for rapid manoeuvres in action. But by introducing steam steerers we are able to provide and manage much larger rudders than could possibly be operated by hand.
Auxiliary Steering Screws. This method of increasing the handiness of vessels has been proposed by a Hungarian engineer.* The feature of the plan is a secondary screw (as shown in the diagrams) which is connected by an universal joint, of simple construction, to a projection of the main shaft. The joint consists of two steel double-eyed forks; between these forks is inserted a block of phosphor bronze. Into the block screw four pins, coupling the forks to the block, and to each other. A locking pin is then screwed into the block and takes in a groove, concave in form, cut out of the inside ends of the other four pins, which keeps them from working loose. Any form of steam steerer may be used with this apparatus, to insure quick handling of the helm.
The auxiliary screw may be mounted on the after-part of the rudder, as in Fig. 519, Plate 127, or in the rudder, as in Fig. 520. Figs. 521 and 522 show the universal joint, P being the locking pin and A, B, C, D the coupling pins.
By making the secondary screw of coarser pitch than the main propeller, a certain increase of speed has been obtained, assumed to be due to the action of the smaller screw in picking up the slip of the larger.
The apparatus is being fitted for trial to the U. S. tug "Nina."
Vessels which do much of their cruising under canvas, will find disadvantage in the increased drag due to the additional screw. This is probably offset by the value of the second screw to the same vessel when under steam alone. Tables given in Appendix L illustrate the performance of the steamer "Stratheden" (2,000 tons), with and without the attachment.
The most important advantage claimed for this apparatus is its immediate effect upon the ship's head. As soon as the helm is moved, a decided turning effect commences, whether the engines are reversed or continued running in the same direction.
Whether improvement is to be in the direction of twin screws, steam steerers, or other agencies, it is certain that, handiness must increase greatly in modern men-of-war, if the ram and torpedo are to be elements in naval warfare. To profit to the fullest extent by such improvements, experience in handling vessels under steam alone must be an essential part of a young officer's education.
It would be idle to deny the existence of a prejudice against the discussion of many questions which relate to manoeuvres under steam. Nor is such prejudice confined to our own service.
* Mr. J. J. Kunstädter.
"How many naval officers," says Fremantle,* "care to know the number of degrees of helm that can be given to their ships, the tending of the screw to turn the ship unassisted by the rudder, the effect of turning the engines ahead or astern when the ship has head or sternway, or what the reduction of speed by putting the helm hard over? These and other questions are simple points of seamanship; yet an officer who would consider himself disgraced if he could not answer at once as to the lead of the lower studding-sail halliards, which may not be supplied to the ship in which he is serving, will acknowledge without a blush that he does not know if the screw of the same ship is right or left-handed, or how many blades it has."
It would be more practical to realize that while the weather-gage and manoeuvres used in obtaining it have lost their importance, there are more urgent reasons now than ever existed in the old sailing days for good judgment on the part of the officers. Combined with accurate gun practice, the skilful handling of ships, which is seamanship, decides most naval actions. And this is as true when the results are achieved with propellers and steam steerers, as it was when they were obtained with braces, tacks and sheets. The motive power alone has changed-the principle remains.
* "Naval Tactics on the Open Sea," by Captain the Hon. E. R. Fremantle, R. N.
GETTING ON SHORE-LEAKING-HEAVING DOWN.
When a vessel strikes, the first step is to brace aback if on a wind; to clew up and furl everything if before the wind, and if under steam, to reverse the engine. It may be possible, if she has struck on a sand-spit or knoll, to force her over into deep water, otherwise she should be hove off as she went on. The navigator should be at once despatched to sound around the ship, and the boom-boats be hoisted out. Carry out the stream-anchor and bring the cable to the capstan. Have careful hands in the chains by the lead to watch if she moves. Heave round and try to get her off. If she does not start, move the guns and men as necessary to change her trim. If this fails, send out a bower anchor and chain. While the boats are carrying out the anchor, send down the upper yards and top-gallant masts, and prepare to start the water and provisions. If still impossible to move her, start water, heave overboard guns and shot (supposing there is no hope from higher tides), and all heavy weights. The guns should be carried clear of the ship and buoyed, with buoy-ropes strong enough to weigh them. Construct rafts out of spare spars, to carry provisions, water, &c. Of course, if small vessels can be procured they will be used. While lightening the ship a good strain must be kept on the cables by which the ship is to be hove off. This is very important, and every time the purchases are observed to slack up, they should be set well taut again. In case the anchor comes home, back it with the stream.
Do not commence to lighten the ship until an anchor has been planted and a good strain hove on the cable, lest she go further on.
If a vessel is aground forward, shears may be raised over the bows, the heels resting on the bottom and the legs long enough to reach well above the bows; the object being to lift her by means of a heavy shear-head purchase. This method was once successfully tried with the United States sloop-of-war "Vincennes," but would not answer with any but the smaller class of ships.
Another instance is mentioned of a ship having run stem on very hard, and after unavailing efforts to get her off, hung on a rock abaft the foremast. All weights were run aft; balks of timber were placed athwartships forward of
the place where the ship hung, and projecting through the ports; perpendicular shores were placed under these from the ground; slung to the balks, and wedges prepared for driving between their outer ends and the shore-heads. Opportunity was then taken of the first increase of water to set up the wedges, remove the after weights and heave in on the purchases at the same time. On this the ship started immediately; and, by a repetition of the same process of leverage, was completely cleared of the rock.
Vessels draw much less water when hove keel out than when upright or heeling over. It is related that a certain vessel had been driven so far up on shore, in a heavy gale and unusually high tide, as to be considered irrecoverable, and was sold for the mere value of her timbers; the purchaser floated a scow alongside of her at high water, and hove the vessel keel out by her masts, and then warped the pair into deep water.
If the tide commences to fall while the vessel is still aground, she must be shored up to prevent falling on her broadside. The spare fore and main topmasts may be used for this purpose. Weight their heels with kentledge, bend on guys to place them, and let their heads take beneath the fore and main chains. Should she rest too heavily on the spars, send out kedges to the opposite side, and bringing the hawsers to the mastheads, set them taut to steady her. * At the next high tide try her again. If a steamer can be procured, let her tow in the direction you are heaving. If a ship is at hand to assist, she may anchor near, and, taking a hawser from you, heave at the same time.
When the vessel first strikes, and the sails are hove aback, or the engine reversed, the officer of the deck should send men in the lower rigging to shake the ship, sally from side to side, or move the guns aft quickly. These means often suffice to get the ship off.
If a ship bilges, all further efforts to get her afloat are of course abandoned. The first step in this case is to get the boats out, and then to keep her upright, saving as much of her effects as possible.
Ships sometimes get hard and fast after grounding, from neglecting to lay anchors out before lightening.
In some cases, the water close under the stern is too deep for anchoring.
It is reported that the bower anchors of an English man-of-war, that had grounded in the St. Lawrence, were transported over the decks; and, being let go from the quarters with a purchase on each, which was carried to the bows, the ship was hove off.
H. B. M. steamer "Gorgon," of twelve hundred tons and three-hundred-and-twenty-horse-power, was driven on shore
* Unnecessary with a flat-floored ship.
in a gale, near Montevideo, and imbedded in the sand to a, depth of nearly twelve feet. Camels were constructed on the spot, tanks made water-tight by introducing fearnaught and lead within their lids. Boilers were hoisted out and made water-tight, and these, with casks, &c., affording altogether a buoyancy equal to three hundred and sixty-seven tons, were secured under the ship by means of cables passed round the bottom. These appliances, together with screws, and heavy purchases leading to anchors planted astern, being duly pre pared, the ship, on the tide filling the dock that had been dug about her, was rescued from her perilous condition. "The whole operation presents a picture of united energy and skill to which maritime records afford no parallel." The details of these operations have been narrated by one of the 'Gorgon's' officers, not only as an account of the means used to restore the ship, but likewise to point out to the young officer to what advantages the qualities of perseverance and forethought may be applied, if duly cultivated in early life."*
The dimensions of one of the camels, whose buoyancy was equal to sixty-two tons, is as follows:
|Length ||38 feet.
|Height ||7 feet 4 inches.
|Breadth at top ||5 feet 10 inches
|Breadth at bottom ||10 feet 4 inches
The planking was three-inch fir, doubled at the edges, and nailed on over seven frames, each nine inches by five.
Cases have been related where officers have thoughtlessly given the order, on the ship grounding, to let go an anchor. The impropriety of this is obvious, for there is great danger of the ship striking on it and bilging. For the same reason when guns are thrown overboard, care should be taken that they be not placed where there is a possibility of the ship striking on them.
When a ship has touched lightly or run into soft mud, a moderate-sized anchor and hawser run out astern and hove taut, may suffice. Then all that is requisite is to loosen her in her bed. This may be done by running in the guns on one side, and sending all hands on the opposite side to list her; by letting the crew sally from side to side by the stroke of the bell, or, as has been successfully tried on board the practice-ships, by manning the lower rigging and causing the crew to shake together.
If badly ashore, be careful not to bring the heaving-off cables over the stern, so that they may have a tendency to bear it down and press her heel on the bottom. Should both bowers be planted astern, bring the cables to the quarters outside, where hang them; now lash to them your heaviest
* Recovery of the "Gorgon," by Captain Key, R. N. This little work may be found in the Library of the Naval Academy, and is well worth reading.
blocks, say the cat, and toggle the fish block to the forward main deck port, also outside; reeve a hawser for a fall, and bring the hauling part from the cat in through an after port each side, taking one to each capstan, or use one capstan and a deck tackle. This gives a better lead.
SHIP ON SHORE. WEATHER FINE.
THERE BEING MUCH RISE AND FALL OF TIDE.
Out boats and plant stream in best direction. Hoist out spare spars, and commence shoring up as rapidly as possible, as she will be left high and dry at low water. As soon as well shored up and spars lashed and cleated, close all the ports and secure them.
Should it be a coral or rocky bottom, her safety will depend in a great measure on keeping her upright. Besides the spare spars take as many from aloft as possible; remove all weights from aloft, and run the guns in to a taut breeching. Get all weights from the side to the centre of the ship and lash them.
The finer the ship's bottom the more the danger to be apprehended from her heeling, and consequently the more the care required in shoring up.
If a full-bottomed ship, and one with a great deal of dead-rise, were both to get on the same rugged shore, the latter, supposing both to be kept upright, would stand the better chance, as she would rest on her keel alone, while the former would rest on her floor; if the two ships were heeled over and striking hard, the full ship would be in danger of bilging, while the sharp ship's lee side will be water-borne, and the ship striking on her keel.
Should both ships be left high and dry on "a hard" without shoring up, the full ship would be left nearly upright while the other would probably be lying on her beam ends. This is a critical position for a strong ship, and extremely dangerous for an old one.
In the matter of heaving off, the sharp ship, by taking the ground in fewer places and causing less friction, would give less trouble than one with a long, flat floor.
The foregoing remarks show the importance of officers being familiar with the model, or "lines" of their ship.
THE CASE OF THE "MONONGAHELA."
The U. S. steam sloop Monongahela (2100 tons displacement) was thrown on shore by a tidal wave at Santa Cruz, W. I., November, 1867, and an expedition for the floating of that vessel was sent from New York, in the U. S. barque
"Purveyor," taking along all the necessary material and twenty-six picked men, mostly shipwrights and caulkers, under the direction of the late Thomas Davidson, Jr., Naval Constructor, U. S. N.
The working party arrived at Santa Cruz (West End) Jan. 31st, 1868, and found the ship high and dry, broadside on, and heeled over at an angle of 15°. The rudder and steering post were broken, metal connection and main stern post gone below stern bearing, a considerable portion of the stern knee gone, after end of keel and garboard strakes gone for forty-five feet, the remaining keel badly chafed and in places broken to the bottom planking, the starboard bilge chafed nearly through the plank to the timbers in many places, twelve streaks of wall plank under the after pivot port on the port side broken, and the sheer line very much out of place on that side.
The badly chafed places of the starboard bilge were trimmed out and white pine plank filled in, caulked, made tight, and sheathing copper put on this side and the keel. Before the keel could be repaired or the ways put under for launching, it was necessary to raise the ship bodily two feet or more. Not having the power to do that at once, the rolling process was resorted to. This was done by placing white pine timber under the ship, filling the space from the bottom plank to the coral in line with the keel, and about five feet out. Hydraulic jacks were then placed under the port bilge, and the ship rolled on her starboard bilge, to a sharp angle. The keel was then carefully blocked, and the ship rolled back on her port bilge to her original position, the timber increased in thickness, &c., &c. This operation was gone through with several times, or until the keel was raised twenty-six (26) inches. After which, new after keel and garboard strakes were put in, posts and rudder repaired, and timber run out on either side to take the place of metal connection and secure the steering post. The propeller was unshipped and four sets of launching ways put under, extending to the water. Owing to the heavy surf which rolled in continuously, it was found impossible to lay the ways from the bank to deep water singly; and it was decided to prepare them about one-half mile south of the ship and near where she first came on shore. A diagonally braced framework or platform was first made, and on this the ways were laid and secured, and the whole fabric launched and towed to the ship, and the four ways connected at the same time, extending out from the land two hundred and thirty-seven (237) feet, or to 14 feet 6 inches depth of water. After the ways were connected, a very difficult job was performed in getting the depth of water at the blocking spots, which were taken four feet asunder. These depths had to be taken several times and an average adopted to get a correct grade. From the great unevenness of the bottom this was hard
to get correctly. After this, the blocking was secured and the whole mass sunk with kentledge. On the 4th of March an attempt was made to launch, but by the bursting of a 90 ton hydraulic jack the bow of the ship started too soon and had got ribband bound before the stern had got fairly started; when the stern did get started it went very fast, and before the bow could gather way again the stern had become ribband bound. It stopped between blocking, the ways broke, and the ship dropped in six feet of water aft and five feet forward. Fortunately, the packing remained in place, and the keel was kept clear of the bottom 18 to 20 inches. This gave the water a chance to breech through and prevented the sand from banking on the outside. All the material was picked up, new ways fitted and put under, the packing was removed by blasting. Anchors were laid out abreast the ship, and in the direction that she was to be hauled, broadside to; crabs put in place, tackles rove and shores made of white pine timber and plank strong enough. to support the pressure of a 90 ton jack. Six of these shores were made. Tackles, chains, &c., were on the seaward side to haul out; shores, jacks, &c., on the land side, to push out. A jack was placed between each shore and the ship's side, to which both were hung by small tackles about three feet above the water, as also was a small stage on which the man stood that worked the jack.
The other end of the shore was backed by the coral at first, and as fast as the ship moved out the space was filled in with kentledge until a man tending this end was up to his waist in water. The shore was then taken down and lengthened. This was done several times until the last shores made were one hundred and thirty-five feet long and over eight feet wide.
After this manner the ship was pushed slowly out, broadside to, on her ways, until within one foot of floating draft, when the tackles relieved the jacks and in a short time the ship was afloat. The utmost care had to be taken with the tackles in order to preserve their effectiveness for the final effort, as the chains available were not of sufficient size to bear the capacity of the crabs, and were broken several times. They were of little assistance while the shoring out was in progress.
All the material was reshipped on the barque, the topside of the ship and the deck were caulked, and the broken walls planked over. The expedition reached New York on its return early in June, 1868.*
* The foregoing description is from information kindly supplied by Mr. W. F. Noyes, master carpenter at the Navy Yard, Portsmouth, N. H., who was a member of the expedition.
Water passes as the square root of its altitude; that is, if we suppose equal holes to be made in the bottom of a vessel at one foot, four feet, nine feet, and sixteen feet beneath the surface of the sea, the water will rush in the holes with a velocity equal to the square root of their respective depths. If for example, 1 represents the velocity with which it enters at the first hole, the numbers 2. 3, and 4, will represent the velocity with which it enters the others.
After the water has risen in a vessel, it will rush in all the covered holes with the same velocity, regardless of their depths, which velocity will be represented by the square root of the difference between the level of the water within and without the vessel.
Suppose a ship drawing twenty feet to spring a leak sixteen feet below the water line, or four feet from the bottom of the vessel. The velocity with which the water enters this leak is represented by 4; but when the water has risen in the vessel, say eleven feet, the water will then enter with a
velocity = squareroot(20-11) = squareroot(9) = 3; when the water has risen
sixteen feet, the velocity will be represented by squareroot(4) = 2, etc. Hence it will be seen that although the pumps may not gain on the leak at first, yet they may do so after the water has risen inside the vessel above the leak.
In order to discover the locality of a leak, it is recommended to steer in different ways. If the leak increases when going ahead at full speed, it is probably forward, otherwise it is abaft. If it neither increases nor diminishes, it may be on either side; which may be discovered by going on different tacks.
Upon springing a-leak the pumps are at once manned and kept going. The carpenter then endeavors to discover it, and on doing so will stop it if possible from the inside. The hold or fore-peak may have to be broken out for this purpose. Sometimes by listening attentively, the noise of the water rushing in will betray its locality.
If the leak cannot be got at in any other way, and is a dangerous one, a sail may be "thrummed" and placed over the hole from outside.
Sails are thrummed as in making a mat. They are got over the bows, and hauled close up over the opening by guys and tackles. The most expeditious way to thrum a sail is to pour on hot pitch, and then tread oakum over it.
Should the leak be on one side, and near the water line, the ship may be hove about or listed; when the carpenter may get at it and nail over sheet lead, or planking lined with fearnaught.
It is of course advisable, whenever possible, to stop leaks from the outside. Many ingenious devices have been resorted to for this purpose, when the ordinary methods of thrummed sails, mats, etc., have been unavailing.
The U. S. steamer "Proteus," in one of the blockading squadrons, was fitted with a chute for discharging ashes through the bottom of the ship. This consisted of an iron cylinder with the lower end bolted to the bottom of the vessel and the upper end, a little above the water line, closed with a tightly-fitting plate when not in use; the plate moved in and out by a lever, as required.
In a gale of wind the bottom fastenings of this cylinder commenced to work adrift, and a dangerous leak was developed at the lower end of the chute.
To stop the leak, the vessel was hove to, a wooden shot-plug was secured to the end of a rope, and just inside the shot-plug a small line with a deep-sea lead attached was connected to the same rope with a squilgee toggle, a line from the toggle being retained inboard. Shot-plug and lead were lowered through the chute, tending the tripping-line of the toggle. When enough rope had been paid out, the squilgee toggle was pulled out by its tripping-line. The lead went to the bottom, the shot-plug floated up alongside, was grappled from the surface and taken inboard. Using the rope as a marrying line, a heavier line was hauled through the chute, and when its outboard end reached the deck it was made fast to a suitable plug formed of mattresses, hammocks, etc. By manning the other end of the line the improvised plug was hauled under the ship and tightly jammed in the bottom of the ash-chute, stopping the leak and probably saving the ship from foundering.
It is obvious that the reason for not using the heaviest line at first was that the shot-plug would probably not have floated it.
On board a merchant ship an extensive leak in a seam was effectually stopped, from outboard, as follows: The vessel being hove to, a rough bag was formed out of a tarpaulin with a broad flap cut in one side, loosely stitched on and the edge connected with a tripping-line, led to the deck. The bag being filled with sawdust, the mouth was sewn up and the bag drawn by lines passing under the keel to the vicinity of the leak, with the flap side nearest the ship. The flap being torn open by the tripping-line, the sawdust worked out and, mingling with the water, effectually closed the seam.
This method was successfully applied on board the U.S.S. Independence at Mare Island in overcoming an annoying leak in the run of the vessel.
As an instance of closing serious leaks from inboard, the case of the "Worcester" may be mentioned here. This vessel, when flag-ship of the North Atlantic squadron,
worked the Kingston valve entirely adrift from its fastenings during heavy weather, the result being that a solid stream of water nearly a foot in diameter commenced pouring in to the ship. Until some two or three feet of water were in the hold, all efforts to close the leak were unavailing, but finally a nine-inch shot (with its diameter suitably increased by wrapping in canvas) was rolled over the orifice of the leak by men up to their knees in the water. Assisted by the back pressure of the water in the vessel, two or three hands could keep the shot in place until it was secured there by a cross-piece of timber, one end of which was placed under one of the boilers, and the other end wedged down by a shore from under the berth-deck beams.
Should a vessel be found to leak very badly, she may, if in the vicinity of land, be beached, as a last resort; or, if near a harbor, be run in and put aground to keep her from sinking in deep water.
If in danger of going down, anchors, guns, &c., must be hove overboard, boats hoisted out, and rafts constructed for carrying men, provisions, and water.
No rules can be given for such cases. Much depends. upon the example of coolness and energy set by the officers, and the general state of discipline. Much, too, depends in all emergencies upon the professional abilities of officers, their practical knowledge and fertility of resource.
The student is referred for accounts of shipwrecks, for the various means of rescuing people from stranded ships, for constructing rafts, &c., &c., to the professional works with which the Naval Academy library is so generously supplied.
Heaving Down. When vessels have sustained injury in their bottom, and there are no opportunities for docking, recourse is then had to heaving down. Tackles are brought from the mastheads to the shore, or to another vessel, and these being hove on, turn the bottom up out of the water.
The following notes were taken at the heaving out of the United States frigate "Brandywine," at the Navy Yard, Brooklyn.
The wedges of the fore and main masts were knocked out, and the masts got entirely over to the weather partners, the stays were also set up afresh, two extra pairs of shrouds were got over each masthead, and set up to dead eyes toggled with a long strap to the main deck ports. (These shrouds were taken forward of the masts so as to equalize the strain between the forward and after shrouds.) Two small chains were middled and eyes formed in the bights, which were well parcelled; one was put over the mainmast head, and the other over the fore; the ends were taken in through the air ports abreast the respective masts, and well set up to stout Spanish windlasses, which were rigged on
the berth-deck in the securest manner possible; great care was taken that all the shrouds, extra shrouds, and chains, bore an equal strain.
Strong shores were placed against the heel of each mast, with their other ends leading up to the junction of the berth-deck beams to the side, where they were well wedged; these were to windward, and were to counteract the tendency of the heel going out of the step to windward when the strain of the purchases was felt to leeward; other shores had their upper ends resting against that part of the under side of the berth-deck which is directly over the keelson; the lower ends rested on the skin of the hold to leeward about midway between the keelson and the ends of the berth-deck beams, where they were firmly wedged; these were to support the body of the ship when down on her side.
Five bolts, three and a quarter inches in diameter at the large ends, and two and a quarter inches at the small ends, were driven through the side of the ship abreast of each mast, about one foot above the berth-deck, and well secured at their inner ends.
The camels or bolsters (being large frameworks of timber to protect the channels from the heels of the shores, and strong enough to bear the strain), were hoisted up by the pendant tackles and strung abreast the masts to windward. The shores were of white pine, seventy-five feet long, nineteen inches square at the heel, and thirteen and a half inches at the head, with a mortice cut through at each end; two were used for each mast, and they were got aloft by having a large three-fold block lashed at the masthead, and a purchase rove of a five and a half inch manilla fall; the lower block was lashed to the shore about one-quarter from the head, and thus each leg was hove up separately to windward; the masthead lashing was of new well-stretched four-inch rope, ten turns of which were passed through the mortice, round and round, and ten more crossed; the heels resting over the camels, were spread so that one might be as much forward as the other was abaft the mast, were gammoned to the bolts in the side with different sized white rope, after which the gammonings were well frapped together; three spare shores were lashed between the mast and each shore (making six for each mast), at equal distances, and belly lashings were hove on in the same places.
With so much weight on one side, the ship heeled considerably, to counterbalance which, water-casks were lashed on the opposite side, and filled, which brought her upright again.
A large and a small purchase were used for each mast; the large purchase-blocks were four and a half feet in. length, the small ones two and three-quarters; the upper
blocks for the former were lashed to their respective mastheads, above the shores, with seven turns of a nine-inch manilla lashing, the upper blocks of the latter were lashed on with five turns of the same stuff; the lower blocks with their leaders strapped with a long and a short leg were toggled to the spar in the pits.
Three crabs were placed for each mast, one for each purchase, the third as a backer for the large one; these crabs were secured to anchors planted in the ground, which were also assisted by pigs of iron.
An anchor, to which the stream cable was bent, was planted in the water abreast the mainmast, the cable opposite the fore purchase was secured to a pile at a convenient distance abreast the foremast; both cables were taken under the keel through the spar-deck ports, and stout tackles clapped on them; the breast fasts were slacked and the ship hove off a sufficient distance by the cable, after which all was secured.
A pair of small but stout sheers, with a figure-of-eight head lashing and head guys, was raised near each pit and relieving tackles attached to the heads; a relieving tackle was also hooked to bolts in the wharf opposite to each mast and then to the gammoning bolts; the falls were rove, and the ship was steadied by them and the relieving tackles.
All the ballast was now got out and placed over the spar which ran through the pits, and to which the lower purchase blocks were toggled; the berth-deck was scuttled abreast the main hatchway, to leeward, and pumps rigged there; the ship was caulked thoroughly, the lee gun-deck ports closed in and caulked also, together with the air ports and scuppers.
All moveables were passed ashore, and the falls rove, the large falls were of eleven-inch manilla rope, the small one of eight-inch manilla rope; the purchases were three-fold; saddles, with rollers, were placed under the falls from the leaders to the crabs, and every precaution taken to prevent chafe; a spar-maker was stationed at the partners when heaving, to see when and how much the masts came over; the main came to within two inches of the lee partners, and the fore touched gently. As the mast-heads got below the sheer-heads on the wharf, the relieving tackles from the sheer-heads were hooked to stout straps around the mastheads; when keel out, the falls were well stoppered and bitted to the crabs, the relieving tackles hauled taut and shores put under the mastheads to assist the relieving tackles; the purchase falls were well covered with tarpaulins.
Every night the ship was righted, and on Saturday night the falls were unrove; previous to her being hove down the next day the frappings of the gammonings were always hove taut.
The starboard forward main swifter parted in heaving
down the first time, which was the only accident which occurred.
In cases where the vessel has been dismasted, or where it would be impossible to procure sufficient length of purchase falls, &c., the bottom is turned out of the water by means of spur derricks. H. M. S. "Success," for instance, was thus repaired. The upper ends of the derricks were cleated on the ship's side, the lower, to which the purchase blocks were lashed, were secured from rising by turns of the chain cable, that were passed under the bottom from the opposite side, being steadied by guys led from forward and aft.
The after bearings of the "Croesus," a screw ship of twenty-five hundred tons, were, in the absence of a dock, recently repaired by means of a caisson, which, when placed, enclosed the heel of the ship from the foremost stern post aft.
It was formed sloping at the fore part from the base to the top, and sufficiently open at that part to admit the heel, the dimensions being twenty-two feet at base, fifteen feet at top, twenty feet in depth, and nine feet in breadth. Displacement about one hundred tons. It was sunk by loading it with chain cable, which was removed when the caisson was drawn forward into position by guys. The caisson was kept free by constantly working two seven-inch pumps; the stern of the ship being raised in consequence nineteen inches.
THE LIFE-SAVING SERVICE OF THE UNITED STATES.
INSTRUCTIONS FOR SAVING DROWNING PERSONS.-RESTORATION
OF THE APPARENTLY DROWNED.
LIFE-SAVING stations, life-boat stations, and houses of refuge are located upon the Atlantic and Pacific seaboard of the United States, the Gulf of Mexico, and the Lake coasts. Their positions are given in the List of Lights supplied to every vessel of war.
All stations on the Atlantic coast from the eastern extremity of the State of Maine to Cape Fear, North Carolina, are manned annually by crews of experienced surfmen from the 1st of September until the 1st of May following.
Upon the Lake coasts the stations are manned from the opening until the close of navigation, and upon the Pacific coast they are open the year round, but, with the exception of stations at San Francisco, Cal., and at Baker's Bay, Wash. Ter., are not manned, depending upon volunteer effort from the neighboring people in case of shipwreck.
All life-saving and life-boat stations are fully supplied with boats, wreck-gun, beach apparatus, restoratives, &c.
Houses of refuge are supplied with boats, provisions, and restoratives, but not manned by crews; a keeper, however, resides in each throughout the year, who after every storm is required to make extended excursions along the coast with a view of ascertaining if any shipwreck has occurred and finding and succoring any persons that may have been cast ashore.
Houses of refuge are located exclusively upon the Florida coast, where the requirements of relief are widely different from those of any other portion of the seaboard.
Most of the life-saving and life-boat stations are provided with the International Code of Signals, and vessels can, by opening communication, be reported, or obtain the latitude and longitude of the station where determined, information
* From "Instructions to Mariners in Case of Shipwreck," Treasury Department Doc. No. 75. For the organization of the Life-Saving Service of the United States the nation is chiefly indebted to S. I. Kimball, the present Superintendent of that service.
as to the weather probabilities in most cases, or, if crippled or disabled, a steam tug or revenue cutter will be telegraphed for, where facilities for telegraphing exist, to the nearest port if requested.
Destitute seafarers are provided with food and lodgings at the nearest station by the government as long as necessarily detained by the circumstances of shipwreck.
The station crews patrol the beach from two to four miles each side of their stations four times between sunset and sunrise, and if the weather is foggy the patrol is continued through the day.
Each patrolman carries Coston signals. Upon discovering a vessel standing into danger he ignites one of them, which emits a brilliant red flame of about two minutes duration, to warn her off, or should the vessel be ashore to let her crew know that they are discovered and assistance is at hand.
If the vessel is not discovered by the patrol immediately after striking, rockets or flare-up lights should be burned, or, if the weather be foggy, guns should be fired to attract attention, as the patrolman may be some distance away on the other end of his beat.
Masters are particularly cautioned, if they should be driven ashore anywhere in the neighborhood of the stations, especially on any of the sandy coasts where there is not much danger of vessels breaking up immediately, to remain on board until assistance arrives, and under no circumstances should they attempt to land through the surf in their own boats until the last hope of assistance from the shore has vanished. Often when comparatively smooth at sea a dangerous surf is running which is not perceptible four hundred yards off shore, and the surf when viewed from a vessel never appears as dangerous as it is. Many lives have unnecessarily been lost by the crews of stranded vessels being thus deceived and attempting to land in the ship's boats.
The difficulties of rescue by operations from the shore are greatly increased in cases where the anchors are let go after entering the breakers, as is frequently done, and the chances of saving life correspondingly lessened.
Rescue with the Life-Boat or Surf-Boat. The patrolman after discovering your vessel ashore and burning a Coston signal hastens to his station for assistance. If the use of a boat is practicable, either the large life-boat is launched from its ways in the station and proceeds to the wreck by water, or the lighter surf-boat is hauled overland to a point opposite the wreck and launched, as circumstances may require.
Upon the boat reaching your vessel, the directions and. orders of the keeper (who always commands and steers the boat) should be implicitly obeyed. Any headlong rushing and crowding should be prevented, and the captain of the vessel should remain on board, to preserve order, until every other person has left.
Women, children, helpless persons, and passengers should be passed into the boat first.
Rescue with the Breeches-Buoy or Life-Car. Should it be inexpedient to use either the life-boat or surf-boat, recourse will be had to the wreck-gun and beach apparatus for the rescue by the breeches-buoy or the life-car.
A shot with a small line attached will be fired across your vessel.
Get hold of the line as soon as possible and haul on board until you get a tail-block with a whip or endless line rove through it. This tail-block should be hauled on board as quickly as possible to prevent the whip drifting off with the set or fouling with wreckage, &c. Therefore, if you have been driven into the rigging where but one or two men can work to advantage, cut the shot-line and run it through some available block, such as the throat or peak halliards block or any block which will afford a clear lead, or even between the ratlines, that as many as possible may assist in hauling.
Attached to the tail-block will be a tally-board with the following directions in English on one side and French on the other:
"Make the tail of the block fast to the lower mast, well up. If the masts are gone, then to the best place you can find. Cast off shot-line, see that the rope in the block runs free, and show signal to the shore."
The above instructions being complied with, the result will be as shown in Fig. 1.
As soon as your signal is seen a three-inch hawser will be bent on to
the whip and hauled off to your ship by the life-saving crew.
If circumstances will admit, you can assist the life-saving
crew by manning that part of the whip to which the hawser is bent and hauling with them.
When the end of the hawser is got on board a tally-board will be found attached, bearing the following directions in English on one side and French on the other:
"Make this hawser fast about two feet above the tail-block, see all clear, and that the rope in the block runs free, and show signal to the shore."
These instructions being obeyed, the result will be as shown in Figure 2.
Take particular care that there are no turns of the whip line round the hawser before making the hawser fast.
When the hawser is made fast, the whip cast off from the hawser, and your signal seen by the life-saving crew, they will haul the hawser taut and by means of the whip will haul off to your ship a breeches-buoy suspended from a traveller-block, or a life-car from rings, running on the hawser.
Figure 3 represents the apparatus rigged, with the breeches-buoy hauled off to the ship.
If the breeches-buoy be sent, let one man immediately get into it, thrusting his legs through the breeches. If the life-car, remove the hatch, place as many persons into it as it will hold (four to six), and secure the hatch on the outside by the hatch-bar and hook, signal as before, and the buoy or car will be hauled ashore. This will be repeated until all are landed. On the last trip of the life-car the hatch must be secured by the inside hatch-bar.
In many instances two men can be landed in the breeches-buoy at the same time by each putting a leg through a leg of the breeches and holding on to the lifts of the buoy.
Children, when brought ashore by the buoy, should be in the arms of older persons or securely lashed to the buoy. Women and children should be landed first.
In signalling as directed in the foregoing instructions, if in the daytime, let one man separate himself from the rest and swing his hat, a handkerchief, or his hand; if at night, the showing of a light, and concealing it once or twice, will be understood; and like signals will be made from the shore.
Circumstances may arise, owing to the strength of the current or set, or the danger of the wreck breaking up immediately, when it would be impossible to send off the hawser. In such a case a breeches-buoy or life-car will be hauled off instead by the whit, or sent off to you by the shot-line, and you will be hauled ashore through the surf.
If your vessel is stranded during the night and discovered by the patrolman, which you will know by his burning a brilliant red light, keep a bright lookout for signs of the arrival of the life-saving crew abreast of your vessel.
From one to four hours may intervene between the burning of the light and their arrival, as the patrolman will have to return to his station, perhaps three or four miles distant, and the life-saving crew draw the apparatus or surfboat through the sand or over bad roads to where your vessel is stranded.
Lights on the beach will indicate their arrival, and the sound of cannon-firing from the shore may be taken as evidence that a line has been fired across your vessel. Therefore upon hearing the cannon make strict search aloft, fore and aft, for the shot-line, for it is almost certain to be
there. Though the movements of the life-saving crew may not be perceptible to you, owing to the darkness, your ship will be a good mark for the men experienced in the use of the wreck-gun, and the first shot seldom fails.
Remain by the wreck until assistance arrives from the shore, unless your vessel shows signs of immediately breaking up.
If not discovered immediately by the patrol, burn rockets, flare-up, or other lights, or, if the weather be foggy, fire guns.
Take particular care that there are no turns of the whip line round the hawser before making the hawser fast.
Send the women, children, helpless persons, and passengers ashore first.
Make yourself thoroughly familiar with these instructions, and remember that on your coolness and strict attention to them will greatly depend the chances of success in bringing you and your people safely to land.
NOTE.-Similar rules apply to the use of the rocket apparatus on the shores of Great Britain.
In the British instructions the signals made from on shore (to haul in, &c.) are made by a man, separated from the rest, waving a red flag in the day time or flashing a red light at night.
INSTRUCTIONS FOR SAVING DROWNING PERSONS.*
1st. When you approach a person drowning, in the water, assure him with a loud and firm voice that he is safe.
2d. Before jumping in to save him, divest yourself as far and as quickly as possible of all clothes; tear them off if necessary, but if there is not time, loose, at all events, the foot of your drawers if they are tied, as, if you do not do so, they fill with water and drag you.
3d. On swimming to a person in the sea, if he be struggling do not seize him then, but keep off a few seconds till he gets quiet; for it is sheer madness to take hold of a man when he is struggling in the water, and if you do so you run a great risk.
4th. Then get close to him and take fast hold of the hair of his head, turn him as quickly as possible on to his back, give him a sudden pull and this will cause him to float;
* From a letter addressed by Joseph R. Hodgson, of Sunderland, to the Royal Humane Society.
then throw yourself on your back also, and swim for the shore, both hands having hold of his hair, you on your back and he also on his, and of course his back to your stomach. In this way you will get sooner and safer ashore than by any other means, and you can easily thus swim with two or three persons; the writer has often, as an experiment, done it with four, and gone with them forty or fifty yards in the sea. One great advantage of this method is that it enables you to keep your head up, and also to hold the person's head up you are trying to save. It is of primary importance that you take fast hold of the hair, and throw both the person and yourself on your backs. After many experiments, I find this vastly preferable to all other methods. You can, in this manner, float nearly as long as you please, or until a boat or other help can be obtained.
5th. I believe there is no such a thing as a death-grasp; at least, it must be unusual, for I have seen many persons drowned, and have never witnessed it. As soon as a drowning man begins to get feeble and to lose his recollection, he gradually slackens his hold, until he quits it altogether. No apprehension need, therefore, be felt on that head when attempting to rescue a drowning person.
6th. After a person has sunk to the bottom, if the water be smooth, the exact position where the body lies may be known by the air-bubbles, which will occasionally rise to the surface, allowance being of course made for the motion of the water, if in a tide-way or stream, which will have carried the bubbles out of a perpendicular course in rising to the surface. A body may be often regained from the bottom before too late for recovery, by diving for it in the direction indicated by these bubbles.
7th. On rescuing a person by diving to the bottom, the hair of the head should be seized by one hand only, and the other used in conjunction with the feet in raising yourself and the drowning person to the surface.
8th. If in the sea, it may sometimes be a great error to try to get to land. If there be a strong outsetting tide, and you are swimming either by yourself, or having hold of a. person who cannot swim, then get on to your back, and float till help comes. Many a man exhausts himself by stemming the billows for the shore on a back-going tide, and sinks in the effort, when, if he had floated, a boat or other aid might have been obtained.
9th. These instructions apply alike to all circumstances, whether the roughest sea or smooth water.
JOSEPH R. HODGSON.
Important to Bathers. Avoid bathing within TWO hours after a meal.
Avoid bathing when exhausted by fatigue or from any other cause.
Avoid bathing when the body is cooling after perspiration.
Avoid bathing altogether in the open air if, after having been a short time in the water, there is a sense of chilliness with numbness of the hands and feet; but
Bathe when the body is of normal warmth, and not overheated.
Avoid chilling the body by sitting or standing UNDRESSED on the banks or in boats after having been in the water.
Avoid remaining too long in the water-leave the water immediately there is the slightest feeling of chilliness.
The vigorous and strong may bathe early in the morning on an empty stomach.
The young, and those who are weak, had better bathe two or three hours after a meal-the best time for such is from two to three hours after breakfast.
Those who are subject to attacks of giddiness or faintness, and those who suffer from palpitation and other sense of discomfort at the heart, should not bathe without medical advice.
RESTORATION OF THE APPARENTLY DROWNED,
1st. INSTANTLY turn patient downward, with a firm roll of clothing under the stomach and chest. Place one of his arms under his forehead, so as to keep his mouth off the ground.
Press with all your weight (placing the hands on each side of the chest), two or three times, for four or five seconds each time, so that the water is pressed out of the lungs and stomach and drains freely out of the mouth. Fig. 523, Plate 128.
2nd. THEN QUICKLY turn patient face upward, with roll of clothing under the back, just below the shoulder blades, and make the head hang as low as possible.
Place patient's hands above his head. Draw the tongue out of the mouth, using forceps, a noose of string or a handkerchief.
Kneel with patient's hips between your knees, and fix your elbows firmly against your hips.
Now, grasping lower part of patient's naked chest, squeezing his two sides together, press gradually forward with all your weight, for about three seconds, until your mouth is nearly over mouth of patient-then with a push, suddenly jerk yourself back. Fig. 524, Plate 128.
Rest about five seconds, then begin again, repeating these bellows-blowing movements with perfect regularity, so that foul air may be pressed out and pure air be drawn into the lungs about eight or ten times a minute, for at least one hour, or until patient breathes naturally.
NOTE. Operate on the spot and at once. Prevent crowding around the patient.
Do not interrupt the first natural effort at breathing. After breathing is regular, rub dry and give hot water and spirits, in small doses.*
The coxswain of each boat should be instructed in the above method, or some other one equally good, and be required to pass quarterly inspection as to proficiency in performing the operation.
TREATMENT OF THE APPARENTLY DEAD.
I. If from Intense Cold. Rub the body with snow, ice, or cold water. Restore warmth by slow degrees, and give stimulants as soon as they can be swallowed. In these accidents it is highly dangerous to apply heat too early.
II. If from Intoxication. Lay the individual on his side on a bed with his head raised. The patient should be induced to vomit, for which purpose emetics may be given. Avoid stimulants.
III. If from Sunstroke. The term may represent one of two conditions, viz.: heat apoplexy and heat exhaustion, requiring different methods for relief. They are thus contrasted:
Heat apoplexy is distinguished by a flushed face, unconsciousness, throbbing temples, heat of head and body, snoring respiration and strong pulse. Treat it by raising the head and shoulders, applying ice or cold cloths to the head and leeches behind the ears, mustard to the lower limbs, no stimulants.
Heat exhaustion is distinguished by a pale face, unconsciousness if present, is partial, no unusual heat of head; body cold, perspiring, or both; breathing quick but not noisy; pulse feeble. Treat it by applying ammonia carefully to the nostrils, administering hot whiskey and water in table-spoonfuls, leaving the head on a level with the body, and applying ice or cold cloths to the head and mustard to the spine, stomach and limbs.
Prevention. Wear, loose and light clothing, with a wet paper or sponge in the hat; avoid the use of spirits, overexertion, over-use of cold water, and exposure in the sun when the thermometer is above 85°, especially if the relative humidity of the air is great.
NOTE. A person who has simply fainted from exhaustion, etc., should be placed flat and the head should not be raised; cold water should be sprinkled liberally on the face, and the extremities chafed to restore circulation.
* Method suggested by Benjamin Howard, M. D., F. R. C. S.
APPEARANCES WHICH GENERALLY INDICATE DEATH
"There is no breathing or heart's action; the eyelids are generally half closed; the pupils dilated; the jaws clenched; the fingers semi-contracted; the tongue appearing between the teeth, and the mouth and nostrils are covered with a frothy mucus. Coldness and pallor of surface increase."
The above remarks are copied from the instructions of the Royal Humane Society. Recent experiments, notably those of the late Dr. De Labordette, of the French Life Saving Association, tend to disprove the belief that "clenching of the jaws" is a sign of death. According to that authority, the first clenching of the jaws after a few minutes of immersion is a proof that life still exists. At any rate, it should not be accepted by an unprofessional person as a sign of death.
It is presumed that in no case efforts to restore life will be abandoned excepting by competent medical advice.