Detail Specifications For Building Motor Torpedo Boats, March 1944, provides the builders specifications for PT 565-624. Numerous details about PT Boats appear in the manual that provide insight to both the technology and the life aboard PT Boats.

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Richard Pekelney


Photo of manual cover.

PT 565-624

PT 565-624


31 March 1944

NOTE: The Detail Specifications are based on Specifications for Motor Torpedo Boats PT 103 to 138 design No. 80-N-3 (dated 2 January 1942) and addenda thereto (dated 22 February 1943), as prepared by Electric Boat Company, Elco Naval Division, Bayonne, N. J., with the minimum modifications made by the Bureau of Ships to make the hull specifications applicable to PT 565-624 Class.

Department of the Navy Bureau of Ships




These specifications and all general specifications, detail specifications, plans, and other data or information relative to these vessels shall be regarded as strictly confidential, and the contractor shall exercise every possible precaution to prevent such confidential information being divulged to unauthorized persons, and especially to those not citizens of the United States.

For ready reference purposes, excerpt from the Espionage Act of June 15, 1917 (50 U. S. C. 31-32), is quoted below:

* * * Whoever, lawfully or unlawfully,, having possession of, access to, control over, or being entrusted with any document, writing, code book, signal book, sketch, photograph, photographic negative, blueprint, plan, map, model, instrument, appliance, or note related to national defense, wilfully communicates or transmits or attempts to communicate or transmit the same to any person not entitled to receive it, or wilfully retains the same and fails to deliver it on demand to the officer or employee of the United States entitled to receive it; or whoever, being entrusted with or having lawful possession or control of any document, writing, code book, signal book, sketch, photograph, photographic negative, blueprint, plan, map, model, note, or information relating to the national defense, through gross negligence permits the same to be removed from its proper place of custody or delivered to anyone in violation of his trust, or to be lost, stolen, abstracted, or destroyed, shall be punished by a fine of not more than $10,000 or by imprisonment for not more than 2 years, or both. * * *

The contractors are reminded that the foregoing applies to the loss of confidential specifications, plans, and other confidential data furnished them by the Bureau.

Further, it is particularly emphasized that no information concerning the general or detailed characteristics of the machinery or appurtenances for these vessels will be divulged to any person or persons not citizens of the United States for the purpose of obtaining any plans or technical information concerning such machinery from any foreign source.




Section Page
A-1. General 1
A-2. Summary of work pertaining to hull to be done by contractor 2
A-3. Work pertaining to other bureaus 3
A-4. Uncompleted work 3
A-5. Ordnance and ordnance outfit 3
A-7. Miscellaneous articles 4
A-8. Care of hull during construction 7
A-9. Inspection 7
B-1. Plans and specifications 8
C-1. Workmanship 11
C-3. Access to compartments 12
C-5. Overweight 12
C-6. Materials 12
C-7. Pickling and cleaning 13
C-8. Galvanizing 13
C-9. Painting and varnishing 13
D-1. Testing, general requirements 14
D-2. Compartment testing 15
D-3. Tests of systems 16
E-1. Stem 16
E-2. Fastenings 16
F-1. Transverse framing 16
G-1. Planking 17
H-1. Keel 17
H-3. Longitudinal framing 18
H-7. Guards 19
I-1. Deck 19
I-3. Deck coverings.. 20
I-4. Flats and floors 20
J-1. Bulkheads 21
K-1. Splinter protection 21
M-1. Struts 22
M-2. Shaft logs 22
M-3. Rudders 22
N-1. Foundations and special framing 22
O-1. Deck houses 22
O-4. Bridges 23
O-5. Windshield 23
R-1. Doors 23
R-3. Hatches 23
R-7. Airports and windows 23
R-10. Screens 23
U-5. Boat and life raft stowage 24
U-8. Steering system 24
U-11. Drainage system 24
U-16. Plumbing 24



Section Page
U-20. Ventilation and heating 25
U-23. Fire extinguishing system 25
W-1. Compartments 26
X-1. Joiner work 32
Y-1. Grab rods and rails 32
Y-3. Warping, mooring and towing fittings 32
Y-4. Life rails and stanchions 33
Y-9. Rubbing and chafing plates 33
Y-11. Labeling 33
Y-12. Canvas outfit 33
A1. General requirements 35
S1. Plans and material 39
S1-1. Plan requirements 42
S1-2. Materials, workmanship and installation 46
S1-3. Bolts, studs, nuts, screws, etc 46
S1-4. Welding and brazing 47
S8. Trial requirements 47
816-1. Floor plates, gratings, ladders, etc 49
S19-1. Painting and preservation 50
S24-7. Remote indicating magnetic compass equipment 50
S28-1. Designation and marking, machinery installation 50
S28-2. Designation and marking, electrical installation 50
S29-1. Weights, machinery 51
S31-1. Spare parts 52
S38-1. Heaters, gasoline 53
S38-3. Bracket fans 53
S39-1. Heat insulation and lagging for piping and machinery 53
S41-3. Main propulsion and auxiliary gasoline engines 53
S43-1. Shafting, main propulsion 56
S43-2. Bearings, propulsion shafting 56
S44-1. Propellers 56
S45-1. Lubrication system 57
S47. Pumps 57
S48-1. General piping systems 57
S48-4. Whistles and sirens-application and installation 58
S51. Boilers 58
S55-1. Fuel storage and burning system 59
S56-2. Feed water systems and tanks 59
S58-1. Distilling plant 59
S59-2. Refrigeration plant 59
S60-1. General requirements for electrical machinery 60
S61-1. D. C. generators-ship's service 60
861-3. Motor generators and their shipboard application 61
S62-1. Panels-electric power distribution 61
S62-2. Electric cables, electric power distribution 65
S62-3. Electric wiring equipment, electric power distribution 66
S62-4. Storage batteries, electric power distribution 67
S62-5. Electric protective devices, electric power distribution 67
S62-6. Power system, electrical distribution 67
S63-3. Shipboard applications of direct current motors 68



Section Page
S64-1. Lighting system, distribution 68
S64-2. Lighting system, fixtures 70
S65. Interior communication 70
S65-1. Telephone systems-shipboard application 71
S65-3. Voice tubes 71
S65-4. Electrical signal and indicating systems 71
S65-5. Mechanical telegraph, signal and indicating systems 72
S66-1. Searchlights-shipboard applications 72
S67. Radio installation 72
S67-5. Search radar installation (Circuit 2R-ER) 73
S67-6. I. F. F. equipment 73
S69-3. Portable electrical instruments 73
S71-1. Electrical fire control signal and indicating systems 73
S91-1. Shop equipment 74


A-1-a. Principal dimensions.-The following data are for information only.

Feet Inches Gallons
Length overall 80 3
Length des. L. W. L 73 4
Beam, over planking, max 20 7
Beam, extreme 20 10 3/4
Depth, molded, top of deck at side to under side of keel amidships 8 9 1/2
Draft, normal, under 28" propellers 5 0 3/4
Potable water, approx. 200
Fuel (gasoline) 3, 000

It is the intent of these specifications to describe the hull construction, fittings, systems, machinery installation, and equipment, all of which are to follow best commercial practice except as otherwise stated, as specially applied to high-speed vessels of this character.

Where the specifications and plans differ, the specifications shall apply.

In the case of details which it is not possible fully to specify, or of inadvertent omissions from the plans and specifications or inadvertent inclusions therein, it is to be understood that the intent of the plans and specifications is to be carried out in all respects and also that the supplying and installation of all fittings and outfits are to be in accordance with what is considered to be the best practice for boats of this type.

The builder shall supply only such items of equipment and outfit as are specifically listed in these specifications. Spare parts will 30 be acquired under separate contract.

These specifications contemplate the installation and/or stowage for Government furnished material as listed in these specifications, and the builder is to be reimbursed for any additional costs incurred if required to install Government material other than, or in addition to, that specified herein.


The contractor shall supply all necessary materials except as otherwise specified. The contractor shall build, launch, and fit out the vessel. The vessel shall be made complete in all respects by the contractor, with all compartments and spaces with their contents, as described by the contract plans or the specifications. The vessels shall be fitted complete with the necessary equipment for steering, towing, warping, stowage, and with such other arrangements as may be necessary for the proper handling, operating and controlling of the vessel and its equipment.

The contractor shall install, the systems complete for the following: gasoline, fire extinguishing, fresh water, lubricating oil, plumbing, pumping and drainage, salt water, ventilation, and such other systems as are necessary. The contractor shall also furnish the above items, except those specifically mentioned as being supplied by the Government.

The contractor shall provide the necessary foundations and connections to systems required for the installation of auxiliary machinery, main propelling machinery, ordnance, searchlights, miscellaneous equipment furnished by the Bureau of Ships or other Bureaus of the Navy Department, as specified in the detail and special specifications, but subject to section A-1 hereof.

The contractor shall perform such work and furnish such materials as may be necessary for the installation of systems, appliances, apparatus, fittings, instruments and utensils, and articles of equipage under other Bureaus, the installation of which is required by these specifications and which is under the cognaince of the Bureau of Ships. The contractor shall install all ordnance equipment, outfit, appurtenances, and instruments, subject to section A-1.

All machinery, tools, appliances, and supplies of all kinds required in building the vessel shall be supplied by the contractor.

The contractor shall also provide and install all fittings and appliances required for the trials which may be necessary to enable the representatives of the Government to determine whether the requirements provided for in the contract have been made, except that for such of these instruments and apparatus as are furnished by the Government the contractor shall be responsible for care, installation and removal only.

The contractor shall install the Government-furnished sectioned whip type radio antenna, with necessary bracing, protective guards, and stowage for all sections when unshipped. See Special (Machinery) Specifications, section S67.


The necessary foundations and attachments, where applicable, shall be provided for all ordnance equipment, outfit and material furnished by the Bureau of Ordnance.

Stowage shall be provided for portable outfit and equipment, furnished by the Government and the contractor, as listed herein.

All work necessary for the proper installation of outfit, equipment, and materials furnished by other Bureaus, as listed herein shall be done by the contractor.

All work under the cognizance of the Bureau of Ships in connection with installation of all systems, appliances, apparatus, fittings, or outfit, pertaining to all Bureaus, shall be done in the most satisfactory manner, and care shall be taken as to location and method of fitting, with a view to preserving structural strength and watertightness in all members.


The vessel when delivered to the Government shall be complete in every respect, but in the case of such items of work as remain uncompleted, the Supervisor of Shipbuilding shall prepare a list, together with a list of all items of work which are found to be unsatisfactory, and submit such lists to the contractor. If desired by him, the completion of the work involved under the items in these lists will be treated as a reduced cost change under the contract, and in this case estimates should be submitted. Otherwise, the completion of such items of work will be undertaken at a Navy Yard at the delivery, and the cost thereof will be deducted from the contractor's account in final settlement.


The battery will be as follows:

Four torpedo launching racks-Mk. 1.

One 20 mm. A. A. gun on mount Mk. 14 on forward 40 mm. foundation.
Four .50 cal. A. A. machine guns in two mounts, Mk. 17 Mod. 1.
One 40 mm. Army type single A. A. gun aft.
One FM smoke screen generator, Mk. 6.

Ordnance and ordnance outfit will be furnished by the Government and installed by the contractor.

The contractor shall provide all foundations and structural work in connection with the installation of the torpedo racks, the .50 caliber A. A. machine guns, the smoke screen generator, after 40 mm. -A. A. guns, Mark 1 side launching racks. Foundations

shall also be provided by the contractor for the possible future installation of one army type 40 mm. single gun forward.

The torpedo director shall be located on the starboard side of the bridge at approximately height of eye.

Nonskid treads shall be added to firing steps in both machine gun turrets.

In all cases, the required space shall be maintained about the guns, when in place for their efficient service at any point in the designated arc of fire. Where fittings necessarily interfere with the efficient service of guns, such fittings shall be made portable.

The contractor shall supply and fit such lashings, padeyes, lashing bolts, and shackles as may be required for properly securing the guns, and torpedoes.

The contractor shall provide stowage for all parts of ordnance outfit and equipment that are not permanently installed.

The contractor will be required to cut the cam-stop blanks for Government-furnished cam-stops for 20 mm. A. A. gun.

Pipe railstops for 40 mm. army type A. A. gun, to protect bridge, torpedo, radar, and other hull interferences, shall be furnished by the contractor.

The contractor shall furnish and install suitable depression stops for .50 cal. A. A. machine guns to give approved clearance of structure, personnel on bridge, etc.

Test-loading and releasing of dummy torpedo from each rack (4 racks per boat) shall be performed after installation.


The following articles will be supplied by the Government and shall be installed or shall have stowage provided by the contractor as directed by the Supervisor of Shipbuilding.

4 Torpedo launching racks, Mark 1.
2 Mk. 17, Mod. 1 mounts for twin .50 cal. machine guns.
1 Mk. 14 22 mm. A. A. mount.
1 40 mm. Army type A. A. gun (stern) with tools and equipment.
1 .50 cal. machine gun spare (packed in box).
2 .50 cal. machine gun Instruction Manuals.
2 sets .50 cal. machine gun sights.
1 box spare parts for .50 cal. machine gun mounts and cradles.
8 ammunition boxes .50 cal., 250 rounds each.
8 ammunition boxes .50 cal., 250 rounds each, spares.
1 Oerlikon 20 mm. A. A. machine gun, 1 box of spare parts and tools, and 1 instruction manual, and 12 magazines.
1 Oerlikon spare barrel.
1 Smoke screen generator Mk. 6 for mounting on stern.
2 Pioneer compasses.
1 Rubber life raft.
1 9-foot Dinghy.
The following articles shall be supplied by the contractor, and shall be installed or shall have stowage provided by the contractor as directed by the Supervisor of Shipbuilding. Articles supplied by the contractor shall be of first quality for the intended purposes, using best commercial articles obtainable where they are satisfactory for the service, and of special Elco manufacture where necessary. In all cases unnecessary weight to be eliminated, and stowage arrangement also to be as light as strength requirements will permit.


4 Transom berth cushions, pantasote covered.
1 Mess seat cushion, pantasote covered.
2 Mess seat cushion backs, pantasote covered. 1 Door curtain, lavatory.
1 Table, mess.


1 "Root"-type berth.
1 Transom and cushion.
2 Thin mattresses.
1 Chair, with cushion.


1 "Root"-type berth.
1 Transom and cushion.
2 Thin mattresses.


1 Seat cushion, pantasote covered.
1 Back cushion, pantasote covered.


1 Seat cushion, pantasote covered.
1 Seat cushion, back.


2 Crews lockers (portable).
2 "Root"-type settees.
2 Mattresses.


1 Observer's seat cushion.


1 M. S. A. explosimeter Model 2.
1 Regular steel shipping cradle per boat, complete with chocks and boat-locating arms. In addition, there shall be supplied one out of every four cradles equipped with rubber-tired wheels and steering linkage.
2 75-pound Danforth anchors, with 5/8" shackle and 3/4" pin.
2 50 Fathoms 4 1/2" sisal anchor rope complete with thimble and shackle. Rig one for service.

**** Page 5, line 38, DELETE"1 M.S.A. explosimeter Model 2." - to read - "Instrument, Electric measuring combustible - gas - indicating portable - Type A of BuShips AD Interim Spec 18 I 19 (BuShips ltr. 11-4-44, PT565-624/S87(516f) ****

**** Officers' Mess The officers' mess furniture will be removed. (BuShips ltr. to Elco dated 30 June '44 PT565-0624/S38-2/S38-1) ****

1 6 fathoms 3/8" galvanized chain with 1/2" shackle and 5/8" pin.
2 Life rings, 24" kapok with chocks and life line.
1 Sea anchor and oil can.
6 Hand Lux 7 1/2 pound fire extinguishers.
14 Life preservers, kapok, jacket type.
2 Cowl vents.
3 Cowl vent covers, canvas, color adapted to camouflage.
1 Oerlikon gun cover, canvas.
1 M. G. turret spray shield cover, aft, canvas.
2 M. G. turret covers, canvas.
4 Dock lines, 10 fathoms, 7/8" diameter.
**** 1 1/8" Per Sales O. N3417-7-21-44 ****
2 Heaving lines, 10 fathoms, 3/8" diameter.
4 Fenders, 7" by 24" with becket and lanyard.
2 Coir deck mats.
1 Bow flagstaff and halyard.
1 Stern flagstaff and halyard.
2 Boat hooks 10 ft., ash.
2 Life lines, wire rope, complete with necessary fittings and stanchions for forward deck to suit.
2 Life lines, wire rope, complete with necessary fittings between Mk. I racks.
2 Trouble lights, with cords and bulbs.
1 Gasoline fuel rod, wing tank.
1 Gasoline fuel rod, center tank.
2 Fuel cap wrenches.
2 Water tank cap wrenches.
5 Padlocks with keys (Corbin 9026 No. 2881).
12 Stools, folding canvas.
1 Rubber mat for bridge.


16 Crew's locker keys.
2 Key locker keys.
2 Keys, captain's room.
2 Keys, spare room.
2 Captain's wardrobe keys.
2 Keys, officer's spare wardrobe.
1 Bridle, towing; stock 10T with pennant.
1 Torque wrench No. 66.
12 12" hose clamps.
2 jars aluminum alloy thread lubricant.
1 1 13/16" socket wrench for propeller shaft flange nuts.
1 Allen set screw wrench for inlet scoop control.
1 Socket wrench for scoop.
1 Life line, wire rope, complete with necessary fittings, for after deck, loose on board.
2 Binnacles for 2 Government-furnished compasses.
1 Wrench for rudder bearings.
4 Ice trays for refrigerator.
1 Strainer and plug for galley sink.
1 Garbage receptacle.
1 Emergency tiller bar.
1 24 volt D. C., 115 Volt A. C. electric stove, 3-burner, portable oven type.


The set cooking utensils included with stove consisting of the following:

1 Portable oven.
1 Oven baffle.
2 Covered oven pans.
1 Open oven pan.
1 Aluminum coffee pot.
2 6-qt. pots with strainers and steamer.
1 Aluminum frying pan.
1 Frying. pan pot holder.
1 Pot holder 6-qt. cooker.
1 Pot holder, percolator.

For other Government-furnished articles see Special Specifications for Machinery, dated 15 April 1944.


These boats are to be constructed in the Elco Naval Division Plant on Newark Bay, at Bayonne, N. J.

Care shall be taken to preserve the structure, deck coverings, fitting, equipage, outfit, furniture, paint work, auxiliaries, appliances and apparatus in a satisfactory condition during the entire period of construction and fitting out. Special measures shall be taken where necessary or directed by the Supervisor of Shipbuilding to prevent the usual wear and tear and damage incident to construction, and to prevent corrosion, especially to unpainted and polished parts of machinery and fittings, and to prevent corrosion and freezing between moving parts. All defects, damages, and deteriorations of the vessel, its parts, fittings, outfit, etc., that develop during the construction and fitting out, or incident to the construction and fitting out, shall be corrected by and at the expense of the contractor.

Just before the delivery of the vessel to the Government all tanks, piping, fixtures, valves, pumps, and all other systems or parts of systems through which it is intended that any part of the potable water supply of the vessel shall flow, or in which it is intended that such water shall be stored, shall be thoroughly flushed with an approved nonpoisonous, noncorrosive, and antiseptic solution in such manner as approved by the Supervisor of Shipbuilding.


By accepting a contract to which these specifications are applicable, the contractor recognizes and acknowledges his obligation to cooperate with the Government in the efforts of the latter to

administer the inspection service efficiently and economically, and he undertakes to protect the interest of the Government, other contractors, and himself, by avoiding actions or omissions which add unnecessarily to the burden on the inspection service. The Government undertakes to complete, with reasonable rapidity, the inspection of all work.

The work of construction shall be at all times open to the inspection of the Supervisor of Shipbuilding and his assistants, and every facility afforded such inspectors for the prosecution of their work. The same facilities for inspection shall be afforded to the Naval Inspector of Ordnance and his assistants, insofar as work under the cognizance of that Bureau is concerned.

The inspectors may reject any unfit workmanship or material, or forbid the use thereof.

The contractor shall furnish such samples of materials and information as to the quality thereof and the manner of using the same as may be required, and any assistance necessary in testing or handling materials for the purpose of inspection or test shall be furnished by, and at the expense of the contractor.

The contractor shall supply such blueprints as the Supervisor of Shipbuilding may require for the execution of the work and for the files of Supervisor of Shipbuilding's office.

The contractor shall furnish the Government inspector with copies of all material orders at the time such orders are placed so that such material may be inspected at place of manufacture if the Government so elects.


B-1-a. Contract plans.-The following plans accompany and form a part of these specifications. The intent of these plans is to show the essential general features and arrangements but not the exact details.


Title BuShips No.
Type sections -408111
Steering gear assembly in boat -408112
Cabin arrangement -408113
Bilge drainage system -408114
Inboard profile, hull construction -408115
Profile and table of offsets -408116
Deck arrangement -408117
B-1-b. Working plans.-In addition to the contract plans, the ship contractor shall prepare detail working plans for the construction of these vessels.

All plans prepared by the contractor shall be approved by the Supervisor of Shipbuilding.

Any material ordered on work executed by the contractor before final approval of the plan of the work involved, shall be entirely at the contractor's risk.

These plans shall be prepared in general accordance with the 10 requirements of the General Specifications for Building Vessels of the U. S. Navy, appendix 16, chapter 1.

B-1-c. Finished plans.-The contractor shall furnish for use on each of the vessels two blueprints of each of the following finished plans:

Cabin arrangement.
Deck arrangement.
Diagrams of systems:
  Fire extinguishing.
  Potable water.
  Steering gear.
  Engine room piping.
Docking, general dimensions and data.
Inboard arrangement.
Outboard profile.
Shaft arrangement.
Wiring diagram.

B-1-d. Plans for squadrons.-The contractor shall furnish for each group of 12 vessels, one reproducible copy of the plans as listed below, applicable to those vessels:

Bilge drainage system.
Bottom blocking.
Lubricating oil system assembly.
Miscellaneous pipe lines.
Underwater exhaust master assembly.
Cabin arrangement.
Lux system arrangement and detail of.
Docking plan.
80-foot motor torpedo boat on cradle.
Inboard profile hull construction.
Towing bitt forward.
Fuel tank installation and construction of tank compartment.
Sections through gun'l, chine & keel.
Type sections.
Deck framing.
Construction of cabin trunk.
Oerlikon ammunition racks and general stowage in rudder compartment.

Ignition circuit wiring diagram.
Torpedo firing circuit wiring diagram. Instrument panel thermal wiring diagram. Gemmer gear outline.
Heat exchanger assembly.
Heat exchanger details.
Heat exchanger tube plate details.
Cooler oil control valve.
Steering shaft gimbal bearing.
Rudder bearings (lower).
Rudder bearings (upper).
Steering shaft bulkhead bearing.
Steering gear chain adjuster.
Steering gear assembly in boat.
Sherwood oil pump assembly (V-drive).
Machinery plan of engine room.
Propeller shaft location.
Exhaust pipe and muffler connection.
Exhaust pipe assembly.
Fore and aft push rod assembly (throttle system).
Mooring bitt.
Bottom blocking.
Bridge control rod assembly (throttle system).
Instrument panel assembly.
Fuel tank fill and sound and suction tube.
Fuel system flow control.
Salt water scoop control assembly.
Fresh water system assembly.
Storage battery power and charging circuit wiring diagram.
General lighting circuit wiring diagram.
Battle lighting circuit wiring diagram.
Power distribution circuit wiring diagram.
Electrical circuit schematic.
Electrical fixtures diagrammatic location.
Audible and visible signal circuit wiring diagram.
Underwater exhaust master assembly.
Outboard profile.
Strut main center.
Strut main wing.
Strut forward center.
Strut forward wing.
Stern tube details.
V-drive assembly.
V-drive shaft and gears.

B-1-e. Plans for Bureau of Ships.-One set of reproducible plans as listed above shall be furnished to the Bureau not later than two months after delivery of the first vessel. When alterations to the above plans are approved, the Bureau shall be furnished with reproducible copy of such altered plans. The contractor shall furnish one blueprint of each plan and each alteration after approval, to the Supervisor of Shipbuilding for forwarding to the Bureau.

B-1-f. Instruction books.-No general information book or damage control book will be required for these vessels. Two instruction books for each hull auxiliary furnished by the contractor shall be provided for use on each vessel constructed.

B-1-g. Photographs.-The contractor shall furnish to the Bureau of Ships photographic negatives of the vessel taken after the vessel is completed or nearly completed. Photographs are, however, required for only one vessel of the class. A broadside view, a bow view about 45° off the centerline, a stern view about 135° off the centerline shall be taken of the vessel lying in stream against a clear background. One photograph of the broadside of the vessel proceeding at full speed against a clear background shall be taken. Photographs showing details of deck and interior arrangements shall be furnished as required by the Supervisor of Shipbuilding.


All workmanship throughout shall be thorough. Any portion of the work, whether partially or wholly completed, if found defective, shall be removed and satisfactorily replaced. Any defects or weakness of structure which may develop before, during, or after trial shall be made good by the contractor.

Particular care shall be taken to insure tightness of all parts of the hull and all parts of systems that are required by the plans or specifications to be watertight, oiltight, or airtight.

Sharp and ragged edges of exposed work in way of access holes, hatches, etc., where liable to injure personnel or equipment, shall be removed. Care shall be taken in all structural work to secure a good shift of butts between the different members.

The workmanship throughout shall be of the best standard for a boat of this type, particular care being taken to insure fair lines and smooth surfaces. During construction and as late as possible before such parts are closed in from proper access, all hull bolts are to be drawn up tight.

All wood plugs are to be set in white lead, shall be put in so that grain will follow same direction as grain of the member in which the plugs are located and shall be cut off flush.

Where practical, all fastening holes shall be bored slightly smaller than the fastenings, but care shall be taken so that driving in of fastenings does not split the members.


Arrangements for access and for cleaning out and painting shall be provided to all compartments and to all parts of the vessel wherever practical. Flooring throughout shall be fitted with suitable hatches, and all gratings in bilges and peaks are to be removable. Care shall be taken in locating pipes and other parts to avoid blocking of access.


During the progress of the work, great care shall be taken in the design of all parts to keep weights down to the minimum requisite for adequate strength and rigidity in order that the designed draft of the vessel under designed conditions of load may not be exceeded in the completed ship.


In general, unless otherwise specified, all materials entering into the construction of these vessels shall conform to the best commercial practice for marine work, as especially applied to highspeed vessels of this type, and as approved by the Navy Department for similar recently built boats.

All material shall be satisfactory to the Supervisor of Shipbuilding. In consideration of the size of vessels and type of construction, it shall be within the province of the Supervisor of Shipbuilding to approve the use of materials other than as specified herein, where such materials may be found more suitable, or where considered equally suitable and more available.

Wherever the use of critical materials is required herein or on the plans, the contractor shall make every effort possible to substitute less critical materials. These substitutions shall be approved by the Supervisor of Shipbuilding. All materials entering into the construction of the vessel, its auxiliaries, fittings, and systems and their appurtenances, and miscellaneous articles of outfit and equipment under the cognizance of the Bureau of Ships shall, except where otherwise specified, be in accordance with the best commercial marine practice for a vessel of this character and shall be satisfactory to the Supervisor of Shipbuilding.


All aluminum which is to be painted shall be cleaned in suitable pickling solution, washed with clear water, dried and painted with zinc chromate primer before receiving regular painting.

All stainless corrosion-resisting steel which is to be painted shall be sand blasted or otherwise suitably cleaned before painting.


In genera], galvanizing shall be done by the hot process and the zinc shall be at least 98 percent pure. Where steel is required to be galvanized, an approved zinc spray may be applied in lieu of hot dipping. The work shall be of the highest quality and shall meet the approval of the Supervisor of Shipbuilding. For structural work, the increase in weight due to galvanizing shall not exceed one-sixth pound nor less than one-eighth pound per square foot of surface covered.

In general, fabricated articles i shall be galvanized in as completely assembled condition as s practicable. Where it is not practicable to galvanize the complete article after assembly, the seams, joints, rivets, and other parts not galvanized shall be cleaned and heavily coated with red lead after assembly.

All steel or iron fittings secured to wood; all steel or iron fittings, which owing to the nature of their use cannot be effectively protected by painting; all clips, hangers, and other small iron or steel fittings, which it may not be practicable thoroughly to paint or which may become clogged with paint, and in general all outside iron or steel fittings except as may be specifically excepted by the Supervisor of Shipbuilding shall be galvanized. Fittings of corrosion resisting steel need not be galvanized.

Galvanizing destroyed by welding may be made good by thoroughly cleaning the material and painting with a heavy coat of red lead.


Vessels shall be painted and varnished throughout, with a sufficient number of coats to preserve the surface and to obtain a satisfactory finish. All fastening holes, etc., shall be carefully puttied, where not plugged. Sanding before and between coats as required for obtaining suitable finish for the service intended.

Topsides shall be primed with Navy formula 5-11 special haze gray, Navy Dept. Spec. 52C45. Fastening holes shall be cemented with smoothing cement, Navy formula 62, Navy Dept. Spec. 52C25. One coat haze gray, Navy formula 5-H shall next be applied. Third (finish) coat shall be in accordance with latest camouflage instructions.

Bottom shall be primed with copper bottom enamel, fastening holes cemented with surfacing putty and finished with two coats copper bottom enamel.

Entire interior shall be painted with one coat of primer, glazed as required, and two coats of fire retardant white paint, Navy Dept. Spec. 52P22. An extra coat of enamel shall be applied to surfaces adjacent to passageways, areas of traffic, and confined spaces as directed by the Supervisor, where personnel traffic would render the fire retardant paint difficult to maintain.

Superstructure shall be primed and finished with three coats formula 511 special haze gray, final coat in accordance with latest camouflage instructions. Decks shall be primed, fastening holes filled with Navy formula 62 smoothing cement Navy Dept. Spec. 52C25 and finished with two coats nonskid deck paint, in accordance with latest camouflage instructions.

Metal work, interior and exterior, shall be pickled where practical, coated with zinc chromate, and painted as necessary, color 25 according to location.

Designating numbers and insignia shall be painted as required.

No red paint shall appear topsides.

The above specifications are maximum requirements and it shall be in the province of the Supervisor of Shipbuilding to authorize modifications where such modifications tend to expedite construction while still obtaining satisfactory results.


D-1-a. General.-All portions of the vessel and all work therein, whether appertaining to the structure, fittings, systems, auxiliaries, or installations, required to be furnished or done by the contractors, shall be thoroughly tested as hereinafter specified or as considered by the Supervisor of Shipbuilding necessary to demonstrate satisfactory workmanship, adequate strength, rigidity, watertightness, oiltightness, airtightness, gastightness, and suitability for the purpose intended, and the provision and maintenance of proper clearances for all moving parts and for all lines of sight and lines of fire, and to demonstrate that all requirements have been satisfactorily fulfilled.


All canvas and rigging shall be tried in place.

All stowage arrangements shall be tested by trying the various articles in place.

In case types of fittings, auxiliaries, systems, etc., are installed to which tests outlined below are not directly applicable, similar tests covering as nearly as practicable the same scope shall be made, together with such additional tests as are appropriate thereto. The details of these tests shall be as approved by the Supervisor of Shipbuilding.

D-1-b. Exterior tests for watertightness.-Upon launching, careful inspection shall be made for leakage of hull, and if such leaks as may appear do not cease within the space of a few days, they shall be corrected as necessary, in a workmanlike manner, including hauling out of the vessel if required.

Decks and superstructures shall be tested by directing against their entire surfaces a stream of water from a hose, at usual city pressure. Special attention shall be given to ports, windows, hatches and fittings passing through decks. Where leaks occur they shall be properly repaired until shown to be tight upon retesting.


Watertight bulkheads shall be carefully inspected for tightness when installed and during construction.

Fuel tanks shall be tested when made by applying 3 pounds per square inch air pressure, which shall be maintained for a reasonable length of time.

The same type of test as described in the above paragraph except that 2 pounds per square inch pressure instead of 3 pounds per square inch shall be repeated immediately before the tanks are installed in the vessel. This test shall be made with the tanks installed in jigs simulating the boat structure.

*** Under Section D-2, Page 15, Line 29, delete:
"2 pounds per square inch pressure" and insert:
".3 pounds per square inch pressure"
Ref: Elco ltr. SWR/gl of 70 July 1945
SupShip, NY 1st end. PT565-624/S1-5
(57720-Sb3)8/21 of 6 August 1945. ****

After the tanks are installed and the gasoline piping installed, the piping system, blanked off from the tanks, shall be tested by applying a pressure of 3 pounds of air to the system, which shall be maintained not less than 12 hours without drop after compensating for temperature changes, as satisfactory to the Supervisor of Shipbuilding.

After the tanks have been installed in the vessel, they shall be subjected to a similar test at pressures as follows:

Wing tanks-2 pounds per square inch.
Center tank-1.2 pounds per square inch.

If during any of the above tests any leaks shall occur, they shall be remedied until shown to be satisfactory upon retesting.


All piping and other systems including carbon dioxide, fresh water, drainage, ventilation, etc., shall be tested to insure that they are in condition to operate properly.


Stem and knee shall be of spruce, sided 5 3/4 inches, molded as per plan and faired into lines of boat. Scarphs shall be plain bevel type, bronze bolted. Stem shall be covered with 1/16 inch brass plate veed over planking, brazed at apex, and fastened with monel wood screws. Stem plate shall continue full length of keel (see section H-1).


All fastenings securing fittings and hardware to hull below water line to be of monel.


Transom shall be of mahogany, 1 1/8 inches thick, planked double-diagonal, with mahogany fashion pieces and spruce stiffeners, and fitted with 1/16 by 3 by 3 inch brass angle capping, on sides and bottom. Transom planks shall be copper riveted together and to fashion pieces and fastened to vertical stiffeners with wood screws. Stiffeners shall be placed to catch bottom girder system, and shall be well bolted thereto. Transom knee of galvanized steel or bronze, welded type with webs to straddle stern post and keel, extending forward to reinforce keel in way of center rudder post.

Frames shall be mahogany throughout. (except laminated bottom frames). Topsides frames shall be sawn in one-piece with 1/2-inch oak facing strip inboard, total molding 5 inches. Siding in forepeak and crew's lavatory shall be 1 1/4 inches, 1 inch in crew's quarters, and elsewhere 7/8 inch, except in way of heavy deck weights and other special locations, where siding shall be increased to 1 inch. Bottom frames shall be sawn type in forepeak sided 1 1/4-inches, and from forward tank compartment bulkhead aft, sided 7/8 inch, except in way of propellers and struts, and in special locations in engine room, where siding shall be 1 inch. Sawn frames shall be molded 5 inches in forepeak, and rudder compartment,

and 6 inches in engine room and tank compartment, including 1/2- inch oak facing strip on top. Bottom frames throughout crew's lavatory, crew's quarters, and officers' quarters shall be sided 1 inch, laminated of oak, spruce, and mahogany to a total molding of 5 1/2 inches in crew's quarters, and 6 inches in officer's quarters. Sawn frames shall be as per plan, varying between 9- and 16-inch centers, to suit load requirements, with steam-bent intermediate bottom frames 7/8 by 1 3/8 inches from bow to forward bulkhead of tank compartment, also in special locations elsewhere as per plan. Frames shall be fitted with double 5/16-inch plywood gussets at deck, chine and keel. Special stiffening and increased gusseting shall be fitted in way of heavy deckloads and in special locations as per plan. All plywood gussets and brackets shall be glued in addition to fastenings (see Deckbeams).

Diagonal bracing of mahogany, 7/8 by 3 inches, shall be fitted on every frame to deck beam, except in way of bulkheads and special stiffening. All faying surfaces shall be glued.


Planking shall be mahogany in two layers, laid diagonally in opposite directions; total thickness of topsides 3/4 inch, inner 5/16 inch and outer 7/16 inch; and of bottom 15/16 inch, inner 7/16 inch and outer 1/2 inch. Planking shall be interlaid with aeroplane fabric and marine glue. Topside planking shall be fastened with bronze screws and copper nails; underwater portion aft to have monel screws and copper nails.

For special inner (third) course of planking, see Section 11-3.


Keel of spruce, shall be sided 5 3/4 inches, molded as per plan, minimum 4 1/8 inches. Keel shall be bevelled to receive planking full width, not rabbetted. Keel scarphs shall be plain bevel type, ratio 6: 1, with mahogany back-blocking, bronze bolted, and copper riveted. Cheek pieces of mahogany 1 1/8 inches thick shall be fitted both sides of keel in way of center line shaft log. Similar cheek pieces 1 3/8 inches thick shall be fitted in way of center main strut. Cheek pieces shall be glued and fastened with wood screws. Keel plate full-length shall be of brass 3/32 by 6 inches veed over planking, and fastened with monel wood screws.


Chine log shall be of spruce aft and oak forward (approximately 1/4 length), and shall be sided 2 1/2 inches and molded 4 1/2 inches, bevelled on two sides to receive planking, which shall land full width butting at intersection. Chine log shall not be rabbetted. Chine shall be through-bolted on alternate frames (on about 24-inch centers) to an angle bracket bolted through chine corner gussets as per plan. Chine guard, inner, shall be of spruce 1 1/4 by 4 1/2 inches; outer, oak 3/4 by 3 1/2 inches. Gunwale clamp shall be of spruce 1 3/4 by 5 inches about 3/4 length aft, forward oak, tapering to stem.

Main shelf shall be mahogany 7/8 by 1 1/2 inches, tapering at ends. Subshelf shall be intercostal, of oak or mahogany 1 3/4 by 2 1/2 inches full length. Guard shall be spruce, sided 3 1/4 inches, with 3 inch face, molded as per plan. Guard capping, oak 3/4 by 3 inches, edges rounded.

Plank battens shall be spruce 7/8 by 1 1/2 inches throughout. The topside battens shall Am diagonally, spaced about 14-inch centers, and bottom battens shall run fore and aft on 6 inch centers. All battens shall be slightly rounded on inboard corners to avoid sharp corners in frames where notched to receive battens. Solid mahogany planking 1/2 inch thick in way of fuel tank compartment, and extending approximately 1 ft. beyond the bulkhead at each end shall be substituted for bottom battens. Bottom battens shall be checked into this inner planking extending one frame bay into tank compartment each end, and riveted to outer planking.

Solid bottom fill planks of 7/8 inch mahogany shall be fitted from transom to one frame bay forward of after bulkhead of engine room, and between chines, the regular plank battens being checked into this solid fill to a point one frame bay abaft the bulkhead. Three planks each side in way of wing shafts, shall extend forward the full length of engine room to tank compartment third skin, reducing in thickness from 7/8 to 1/2 inch just forward of shaft log. Special joggled butt-block shall be fitted over this step down in thickness. Additional backing blocks in way of struts, rudders, etc., as required, shall be fitted.

Side ceiling battens shall be spruce, 7/8 by 4 inches, in way of topsides full length of ship intercostal between bulkheads except where replaced in tank compartment by solid panels of plywood. Lower course in engine room shall be of mahogany.

Engine bearers and girders shall be constructed with 1/2 inch birch plywood webs and mahogany booms top and bottom, except in engine room, where the girders shall be constructed of 3 webs

of 1/4 inch birch plywood with inside booms of mahogany, sided as per plan.

Girders shall be deep molded as per plan, and shall be metal bracketed to every frame. Girders shall aline continuously fore and aft, and shall be intercostal between bulkheads with strongly bracketed through connections. Special intercostal girder seating to skin in tank compartment, the inboard girder being bracketed top to bottom.

Girders shall be alined along upper chord with floor bearers, and special bracing fitted to topsides framing with diagonal struts forward on alternate frames. All connections through metal brackets, through fastened, and plywood gussets as required. All wood to wood members shall be glued.


(See also longitudinal framing, Section II-3.)

Supplementing main guard, a guard clamp, about 3/4 length from stern, shall be of oak 1 1/8 by 3 3/4 inches shouldered below clamp and bolted through planking and gunwale clamp. Main guard shall be through bolted on every main frame, except at bulkheads, to an angle bracket bolted through gunwale gussets, as per plan.

Guard across transom shall be built up of two courses of spruce shaped to bevel of transom to place guard cap plumb. Inner course shall be molded 3 1/4 inches below deck plywood, outer course shall be sided 2 7/8 inches and molded 3 1/4 inches, being set with top flush with upper side of deck plywood. Guard cap shall be of oak 1 1/8 by 3 1/4 inches, to give a total projection aft of transom of 6 inches, to protect exhaust mufflers. A brass strap shall be bent around each outboard corner of guard cap, and fastened with wood screws.


**** Line 33: "of plywood having 5/16" fir core with cross banding each side of 1/20 birch, and faced on each side with 1/12 mahogany." (Per BuShips ltr. 10 June 1944 PT565-62/S11-6 (516f) (Hull Change I-1-(1) Elco S.O. N3385 ****

Decking shall be single layer of mahogany plywood, approximately 9/16 inch thick, installed in general accordance with plan, BuShips No. PT486-S1106-411193, subject to development of satisfactory material. Covering board and plank sheer shall be of mahogany. Beams shall be of mahogany, sawn type, molded 6 inches and sided 1 1/8 inches throughout except at hatchways, etc., where beams are 1 3/8 inches. Short beams reduced molding except in way of torpedo tubes. Intermediate bent-beams shall be of mahogany 7/8 by 3 inches in crew's quarters, and elsewhere as required. Intercostal bridging in three courses under forward

deck with mahogany stretcher below the beams; the wing courses shall pick up the deck coaming with ample lap-by, resuming at after end of engine hatch and continuing to transom.

Special reinforcing of both deck and topsides in way of torpedo rack deck pads, and 40 mm. gun foundations shall be fitted with stanchions and deep web frames as required. Diagonal metal strapping shall be fitted under deck plank to tie forward mooring bitt to bulkhead next aft of same, and to ship's side. Similar strapping shall be fitted to distribute torpedo tube and the fueling-at-sea bitts reactions as per plan.

Continuous full-length coaming 1 3/4 inches to 1 1/2 by 6 inches and deck shelf 1 1/8 by 9 inches mahogany, shall be through bolted to subshelf below deck beams.

Engine main hatch shall be raised about 7 inches above deck, with transverse beams of deep section at every frame, strongly bolted to main deck, and removable for unshipping engines. Hatchway header shall be mahogany 1 1/8 by 6 1/4 inches bracketed to each beam. The engine room access hatch shall have hinged cover set at approximately 45 degrees on forward side with means for clamping shut, and for holding fully open. The main housing of this hatch shall form an air intake scoop with water traps, light stops, hinged shutter, and drains. The athwartships dimensions of the air intake scoop shall be at least 6 inches wider each side than the hatch cover, or approximately 50 inches over-all.

A welded steel bracket with flanged web and wide flanges shall be bolted in each corner of main engine hatch coaming, also at each after corner and forward port corner of trunk coaming over tank compartment, with backing angle clips on heavy deck beams catching bolts through coaming.


Gun working circles, bridge floor, areas in way of towing and mooring bitts, as required by the Supervisor of Shipbuilding, shall be covered with "Dektred" or equal.


Floor bearers of spruce constitute a part of the framing system, and shall be sided to match the bottom frames, and connected thereto with 5/16 inch plywood gussets, glued and fastened with wood screws. Horizontal bearers and keel posts to be 4 inches molded, with 3 inch diagonal braces on alternate frames in crew's quarters as per plan. Flooring, except in tank compartment and

chart house, shall be balsa-core aluminum covered panels having all edges sealed against moisture. Spacers of mahogany shall be fitted to permit easy and complete access to bilges.

Flooring of chart house shall be of 5/8 inch fir plywood, with mahogany bearers, well fastened to longitudinal bulkhead and with headers as required.

Flooring of tank compartment (day room) shall be of fir or birch plywood, and shall be completely removable for access to or unshipping of fuel tanks. There shall be one main section of flooring mid-length of the compartment, built up in box-panel form which shall include hatch to center tank, and shall have ledges across forward and after sides to support separately removable panels placed in the four corners of the room, also the raised portable steps over fuel tank connections (see Section W-1-k). The entire floor shall be carried on longitudinal sides by heavy cleat on side panels of day room, with parting strips, and designed to function as spreader for inboard supporting panels or chocks, for the wing fuel tanks. All joints shall be closely fitted, and properly landed, to obviate as far as practicable, circulation of gasoline fumes from the tank compartment.


Bulkheads shall be located as per plan, framed with mahogany, and faced on both sides with all-birch plywood,1/4 or 5/16 inch thick, Solid fill of western red cedar at bottom to a point above chine. Both faces glued and screwed to framing, fills, and stiffeners. Side framing shall be molded 6 inches to give solid backing to ceiling battens. All openings shall have rounded corners and plywood doublers. Plywood transverse joints shall occur on solid fill or on inside stiffeners, and shall be closely screw fastened. Bulkheads bracketed to gunwale and chine with welded galvanized steel knees, through-bolted on both legs. There shall be no vertical butt joints of plywood on bulkheads.


Portable armor shall be fitted around helmsman's station, of contractor furnished 1/4-inch protective plating, Navy Dept. Spec. R47S33, fitted with raised platforms forward and aft of transverse panel, for helmsman and/or searchlight operator, and fitted with rubber bumpers on two corners on starboard side, satisfactory to the Supervisor of Shipbuilding.


Struts similar to those furnished by the contractor on Motor Torpedo Boats PT486-544 shall be provided.


Shaft logs similar to those furnished by the contractor on Motor Torpedo Boats PT486-544 shall be provided.


Rudders similar to those furnished by the contractor on Motor Torpedo Boats PT486-544. Rudders shall be tinned with 50 percent tin and 50 percent lead.


Torpedo rack deck pads, 40 mm. gun foundation on forward deck, 40 mm. gun foundation on after deck, built-up of spruce, mahogany, and plywood with under-deck blocking as required.


Superstructure shall be of simple form, all straight sided and plumb, except the raked and angled forward end of radio house and bridge shelter.

The trunk above crew's dayroom shall be built with framed-up plywood side and ends, and top only being removable, to permit unshipping fuel tanks. Any tank may be unshipped independent of the other two.

Top shall be molded plastic or fabricated plywood, covered with aeroplane fabric, doped on, and is provided with means of securely bolting to sides and making watertight transverse joints.

It is unnecessary to dismantle turrets in removing either engine or tank hatches.

The radio and chart house shall be constructed in general the same as the after trunk, but shall have permanently fixed top.

Machine gun turret cylinders shall be 48 inches 0. D. and be located as per plan and constructed of molded plastic plywood, with special connections to after trunk and chart house. Top shall be designed to carry government furnished scarf ring gun mount for twin .50 cal. machine guns. Scuppers to deck at low point of base. Firing steps for depressed fire shall be fitted.

House tops shall have heat insulation of Onazote or equal to within about 8 inches of house sides.



Bridge arrangement shall be in accordance with Motor Torpedo Boat PT486 type arrangement. Aperture for sighting radar scope to be provided to starboard of the throttle location, as approved. Throttles to be located to starboard of the steering wheel.


A wind deflecting airfoil shall be installed over and slightly forward of the steering station.


Watertight doors shall be fabricated of aluminum and plywood, with rubber gaskets and specially designed hinges and quick-operating dogs, located as per plan.


Deck hatches shall be cast aluminum throughout of raised gasketed type with special and improved hardware.

Four lifting eyebolts shall be installed in main engine hatch.


All ports shall be of special type with improved drain pans and scuppers, except in crew's dayroom and chart house sides which shall be fitted with hinged metal ports with integral black-out shutters and equipped with wire mesh insect screens satisfactory to the Supervisor of Shipbuilding. Eliminate windows from forward side of chart house.


Portable insect screens shall be provided to protect all living spaces.

Black-out shutters shall be provided throughout boat, including screens for fixed and hinged windows and ventilators. Screens shall be of solid plywood type, sliding in runners for windows, and under engine room vents, to be combined with spray shields, fitted with drains to deck. Special metal shutter shall be fitted on chart house door. Boots shall be fitted at muffler operating rods at transom. Areas reflecting light near shielded openings shall be painted flat black.

**** Magnetic compasses to be installed in accordance with NY NYK Dwg. No. Sk.-468 (Hull Chg, A-1-(2) 4 June '44 - BuShips ltr. PT-565-624/S24(516f) ****
**** Delete "Airfoil type wind deflector complete with all appurtenances from the vessel." (BuShips ltr. PT565-624/S18(516f) Hull Chg. A-1-(4) 27 July 1944. ****


The life raft shall be mounted in a chock on forward deck, and fitted with canvas retaining chocks and cotton lashings.

Suitable stowage shall be provided for the rubber life raft and the 9-foot dinghy.


The contractor shall provide a steering system similar to that installed on Motor Torpedo Boats PT486-544.


Bilge system comprised of proper piping, with suction strainers in bilge with directional valves, and hand pumps. Automatic bilge bailers shall be fitted to drain each compartment under way, and shall be provided with accessible shut-off cocks. Brass limber chains with return springs shall be fitted in tank compartment and engine room.


Water tank, plastic lined, located below chart house, shall be constructed of welded aluminum, capacity 200 gallons. Hand hole easily accessible in face of tank, shall be provided for cleaning and inspection. Tank cradle of wood, braced to bulkhead, keel and girders, shaped to tank bottom, and lined with 1/2-inch felt in canvas bag. Corrosion-resisting steel strap shall be fitted around upper part of tank, bolted to bulkhead.

Piping and fittings shall be of aluminum to all fixtures. Proper filling pipe leading to bridge, with removable strainer at fill. Gage glass with stop cocks easily visible from passageway below.

Suitable fixtures of high quality yacht type shall be fitted in officers' and crew's quarters. Seacocks shall be fitted on all water closet intake and waste pipes.

Supply from tanks to wash basins shall be by means of hand pumps.

Drain pipes to sea, of copper tubing, shall be fitted.

Electric refrigerator for storage of food shall have a minimum capacity not less than 8 cubic feet (see see. W-1).


Forced ventilation provided throughout the boat by electric blowers and duct system leading to all compartments except engine room and lazarette. Galley also shall have a small blower discharging to deck. Ducts to be of plywood construction covered with aero-fabric doped on. Lead-ins of metal as required. Outlets and exhaust shutters of aluminum.

Natural ventilation through cowl ventilators, the engine room access hatch blind scoop over engine room, as well as through special low-down vents over living quarters (see sec. W-1). Cowls are to be provided with means of swiveling and securing in any position, and to have black-out light and water traps as installed on Motor Torpedo Boats PT486-545.

Drop windows in crew's dayroom and in chart house also provide natural ventilation.

Two screw-down ventilators, mushroom type over lazarette, and two over tank compartments port and starboard. Heating units shall be provided with a capacity of 80,000 20 B. t. u. per hour and shall be equal to or better than the Stewart-Warner Model 906 combustion heater.

One exhaust blower of suitable capacity so arranged as to exhaust heated air at the radar equipment with minimum heated airflow across this equipment is to be provided in the chart room.


The fire extinguishing equipment shall be a remote manually controlled carbon dioxide system, completely installed for protection of engine room and fuel tank compartment. It shall consist of proper capacity of gunfire type cylinders, with watertight pull boxes on the bridge and at a point convenient to engine hatch, for separate flooding of engine room and tank compartments. Tanks shall be located in compartment below chart house, and supply lines run to engine room and fuel tank compartments with proper nozzles. Pressure-operated switch shall be provided to shut off blowers of ventilation system. Controls shall be located at bridge and engine room hatch on deck.

Six 7 1/2-pound size carbon dioxide portable gunfire type hand fire extinguishers shall be supplied and installed in approved locations.

An approved portable gas detection device shall be supplied and stowage provided for same. **** Deleted per BUSHIPS Ltr. P.T.565-674/S87(516f)11-4-44(See Pages) ****


W-1-a. Forepeak.-The forepeak is accessible through removable watertight hatch in the collision bulkhead, and on port side of center line is fitted with a slatted rack of hardwood for chain and anchor rope with fore and aft partitioning as per plan. Starboard side shall have removable solid flooring for miscellaneous small gear. A brass rope deck pipe of ample size with removable cover and keeper chain will be located on port side above rope locker, and a bitter end eye plate for anchor line to be bolted low on the bulkhead. A drain flange with threaded cap to be placed on each side of sampson post and accessible from the after side of bulkhead. Side ceiling battens of hardwood in way of chain and locker rope.

W-1-b. Crew's lavatory.-In addition to the specified plumbing fixtures, this compartment shall be fitted with medicine cabinet on after bulkhead, and a frameless mirror on the forward bulkhead, also, with three grab rails, located on forward and after bulkhead, and on the after end of fore and aft partition. A canvas-lined oil skin drip tray of cedar shall be built above outboard girder at the after end as shown on plan, and a row of coat hooks mounted on bulkhead above. The diagonal deck beam braces shall have stowage battens on inboard side with ample access space left below deck beams.

A special ventilator of welded steel or aluminum with 6 by 6 inch throat shutter, operable from below decks, and water trap, shall be placed above drip tray close to after bulkhead. Fit one fixed deck light above wash basins. Toilet fixtures shall include paper holder and soap dish, the grab rails being so placed as to function as towel bars. Access to compartment through doorway with curtain.

W-1-c. Forward passageway to starboard of crew's lavatory.-To be fitted with a bench above girder and shelves for miscellaneous boat and commissary stores. Also, chocks and lashings for two 75-pound Danforth anchors one below and one on topside as required.

A ladder at the after end on fore and aft partition leads to the deck, and the compartment is reached from the crew's quarters through a watertight door fabricated of plywood and mahogany with handles for operation from either side of bulkhead.

Fit one fixed deck light matching that in crew's lavatory.

W-1-d. Crew's quarters.-Accommodations shall be provided for 8 men in 4 transom berths, and 4 canvas- and roller-type berths fitted with canvas bottoms, over. Lower berths shall follow inboard edge of outboard girder, and shall parallel floor with

transverse bearers and portable plywood tops with finger holes. Crew's lockers in two units shall be placed on forward and after bulkheads as shown, to be framed up of western red cedar, the door frames only being of mahogany. Shelves and top as per plan, each compartment to have individual door, to have latch, lock, and name plate. Door frames to be relieved top and bottom for ventilation. A seat of slatted construction and open below, with cushion and back, and arm on inboard side shall be placed across after bulkhead as shown on plan. Folding table with mahogany top, two drop leaves and one drawer below fixed center portion, shall be mounted on tubular stanchions detachably bolted to inboard girder. Table top shall have rounded edges and low rails on all sides. Stowage battens similar to those in crew's lavatory shall be screwed to inboard side of diagonal beam braces with ample access space below deck beams. A bulletin board, 16 inches by 24 inches, shall be placed above transverse seat, constructed of cork board covered with green baize with mahogany frame. After bulkheads shall be fitted with watertight door fabricated of aluminum and plywood, rubber gasketed all around, and locked with dogs. Two special ventilators shall be fitted in deck of the same type as in crew's lavatory, at after end inboard of life lines (see Deck Plan). Fixed deck lights shall be located outboard of life line as per plan.

W-1-e. Galley.-Galley shall be located to starboard from center line between watertight bulkheads and entered forward through door as described above, and provided with a similar door in the after bulkhead. Arrangement of countersink drain board, and dresser space shall be as per plan, these being constructed of aluminum, with suitable inboard ledges and made tight to flashing of aluminum 10 inches high on forward bulkhead and starboard side 1 inch ledge around inboard edges. The entire area of after bulkhead between outboard flashing and inboard partial bulkhead from top of stove bench to deck shall be covered with aluminum over 1/16-inch sheet asbestos. Similar treatment shall be given inboard side of partial bulkhead. Sink with over-all dimensions 14 by 20 by 6 inches, of commercial porcelain enamel type, with strainer and drain plug, waste pipe leading directly to sea close to chine shall be provided. Waste pipe shall be of 1 1/2-inch seamless copper tubing with outboard clam shell.

Refrigerator shall be lined with aluminum welded to make seamless tank, with 1 1/2-inch cork board insulation covered with tar paper and reinforced as necessary with spruce framing. Front shall be of mahogany with two doors each with spring catch. Interior capacity shall be not less than 8 cubic feet total volume. The after end shall be provided with evaporator unit with four ice

trays and removable drip pan. Main food compartment shall have one 1/2-inch drain tube leading to bilge. Shelves shall be of light gage corrosion-resisting steel well vented and easily removable. Compressor shall be located below sink with door to enclose, and easily accessible for lubrication or other maintenance.

The outboard girder shall project 1 foot above galley floor and be covered with a removable foot board protected with linoleum and aluminum angle strip. Cupboards of western red cedar with door frames of mahogany, and two shelves each with ledges, shall be built below sink board and counter. Cupboard space outboard above refrigerator shall be fitted with partitions and doors, also racks and cutlery drawers to stow specified galley equipment. A bin with hinged cover shall be fitted on bulkhead between above cupboards and stove space, located well clear of dresser top. An additional cupboard shall be placed on forward bulkhead extending from crew's quarters door to inboard cupboard, this shall be of bin construction with compartments about 16 inches wide, each pair of which shall have a common lid. Grab rail shall be strongly affixed to after face of this bin. A similar grab rail shall be placed on inboard side of partial bulkhead beside stove. Galley soap dish shall be mounted above sink and through bolted to bulkhead. Garbage receptacle of rectangular section, metal guides, and jump type retaining strip shall be fitted below counter cupboard and shall be easily removable. Overhead ventilator of trunk type opening below the shelf in chart house with side outlet ventilator on deck house shall be provided. Fit two fixed deck lights to aline with those in crew's quarters. Electric stove and installation on shelf abaft ice box, with lockers below and outboard. Portable oven supplied with stove, shall be stowed on shelf conveniently above stove and securely retained. Stove shall be 24-volt D. C. and 115-volt A. C. (nominal), 3-element, 3-heat type, with latch for anchoring oven in place, and provided with rough water utensil keepers. Stove shall be direct connected to main distributing panel in engine room through circuit breaker switch. (See Special Machinery Specifications.)

W-1-f. Petty officers' stateroom.-This room shall be provided with one transom berth and one boat-type berth and two mattresses. Outboard side shall have close-spaced ceiling battens with pigeonhole recess. Two suitable lockers of plywood with doors fitted with latch and lock, also top shelf hanger bar and four wardrobe hooks shall be provided. Desk of table type 20 by 27 inches with lift top, mounted without leg, on bulkheads, open below. Book rack with adjustable clamp end shall be placed above on longitudinal bulkhead with light fixture recessed below. Fit ventilator and deck lights similar to those in galley.

W-1-g. Officers' stateroom.-This stateroom shall be arranged as per plan, all details similar to chief petty officers' stateroom. The desk shall be 30 inches wide; the bureau shall be of increased size. One suitable bureau and hanging locker in lieu of CPO lockers shall be furnished. In both staterooms the fore and aft bulkhead shall be of plywood with doors opening inward, with knobs and locks operable from either side.

W-1-h. Officers' lavatory.-The lavatory shall be located between officers' staterooms on port side with door opening outward into either, the forward one of which shall be of watertight construction similar to the galley bulkhead door. In addition to the specified plumbing fixtures, this compartment shall be fitted with deep medicine cabinet with mirror door and two shelves inside, and service shelf above wash basin. Linen shelves outboard and above water closet with deep ledges. Toilet fittings shall include paper holder, two wood towel bars, spring-type tumbler holder, toothbrush holder, and paper towel rack. One coat hook shall be mounted on after door, and a grab rail shall be mounted beside water closet on forward bulkhead. Natural ventilation shall be through special ventilator located above water closet located in deck, same type as described for crew's lavatory. Fit one fixed deck light above center of the gangway.

W-1-i. Officers' messroom.-This space shall be fitted with mess table with mahogany plywood top, open below. A small cabinet with two doors and a shelf shall be mounted on forward bulkhead about 18 inches clear of table top. Fit seat at after end, of slatted construction, with cushion, upholstered back, and arm on inboard end; fit fore and aft shelf recessed between frames with deep inboard ledge on inboard side. Fit one fixed deck light in center of compartment. Open archway in bulkhead abaft mess-room shall be fitted.

W-1-j. Ammunition stowage.-To starboard of fore and aft passageway, the entire area will be utilized for stowage of ammunition, small arms, pyrotechnic equipment, etc., to suit military requirements.

Stowage for .50 cal. ammunition shall be provided in crew's dayroom under settee on port side, and in locker on starboard side of bridge, with outboard door, forward of the machine-gun turret. Stowage shall be provided for four boxes of ammunition.

Small arms stowage shall be provided for all items on ordnance allowance list.

Stowage shall be provided for 20-mm. ammunition in 2 watertight deck boxes, fitted with hinged gasketed covers and necessary clamps and padlock staples, mounted on forward deck and adapted to receive 3 ammunition drums each; also below-deck stowage for

6 drums of ammunition shall be fitted with felt bearer strips and hinged covers. Stowage shall be provided for 12 boxes 40 mm. Mk 1 ammunition in the lazarette. Sixty-four rounds, clipped, shall be stowed on deck adjacent to gun.

W-1-k. Crew's dayroom.-Located above fuel tank compartment between watertight bulkheads, with nonwatertight door to forward quarters, and sound-insulating door and hatch in after bulkhead to engine room. This door shall be fitted with double fixed window and provided with gasket seal, and clamp dog from either side, but no lock. A roll-up canvas berth, with portable head-rail, shall be installed each side of cabin, with water repellent covered cushion over canvas for seating purposes. Day room shall be available as temporary infirmary as well as crew's quarters, and shall have crew lockers, medicine cupboard, and shelves worked into after end, according to plan. The floor of the day room shall be removable, as described in section 1-4. Portable steps shall be provided at forward and aft ends to accommodate center tank fuel filling and suction fittings, as well as to provide an access cover over the fuel valves and piping on forward side of after bulkhead. Access to the after machine gun turret shall be through a door cut in the part of turret wall rounding out from the port aft corner of the day room. A stretcher handling door shall be cut in starboard aft bulkhead of the cabin trunk just above the transverse deck coaming, and shall open outward. Access doors to the tank manholes shall be cut in the side panels of the day room between the floor and the deck. In effect, all furnishings above the day room floor shall be easily removable, so that flooring and tank side panels may be removed for inspection or service of the tanks. Above the deck line, the day room shall have 3 windows each side, and one in the forward bulkhead for bridge communication. All windows shall have black-out panels (section. R-7). A fore and aft cabin top stiffener each side of the center line shall be shaped to form an overhead handrail. In the starboard forward corner, a hatch of at least 22 inches square shall be cut, with a hinge back top, to provide an exit from the day room, using a steel ladder with tubular rungs mounted on the house side. The entire center section of the cabin roof shall be mechanically removable, to facilitate the extrication of the fuel tanks.

The sides and top of day room trunk shall be constructed as described in section O-1, and shall include the after port .50 cal. machine gun turret, with main and depressed firing floors, limiting stops, exit door, and adequate drainage, as per plan.


W-1-l. Radio and chart house.-Shall be located forward of the bridge and reached therefrom by a door with fixed window and clamping dog handle bolted on inside. The deck level shall extend inside the chart house on the sides and forward, to form a continuous working table surrounding the floor space. To star board aft there shall be a .50 cal. ammunition locker, opening on deck, but having racks for sub-machine guns on its interior sides. The forward table space shall be reserved for navigation, and navigational equipment, also bookshelf, chart space, and transverse drawers which extend forward to the front of the house itself, having a tray top just under the forward house windows which shall be of fixed type. The port side shall be reserved for all radio and detecting equipment, including a chair against the after bulkhead for the operator. The floor space just forward of the entrance door shall be cut out and hinged as hatch cover, so that the ladder on the bulkhead may extend below the floor and provide a descent to the main floor level below, between the officer's mess and the officer's lavatory partition. The remaining space under the chart room floor, being of low headroom, shall contain the 200-gallon water tank on the forward bulkhead, and the two carbon dioxide tanks for the fire extinguishing system on the after bulkhead. A removable section of flooring between these tanks shall afford access to the bilge. An open arch to starboard shall provide entry to the main passage fore and aft in the boat.

The flooring in the chart house shall be mechanically portable, also a section of the chart house roof, approximately 30 by 54 inches for removal of the potable water tank described above. The flooring shall be fitted for a mat of sponge rubber with ribbed tread.

W-1-m. Engine room.-Engine room, aside from mechanical equipment specified under Machinery Installation and Electrical System, shall have regular aluminum covered flooring in removable sections. Platforms of plywood or metal to suit requirements of safety and access shall be placed over couplings, V-drives, batteries, stuffing boxes, and other moving parts, and shall be coated with nonskid paint where practicable. Tool box and shelf shall be located on port side abreast vee drive. A wooden seat shall be securely mounted on forward end of starboard engine, to permit operator to handle all 3 reverse gears, scoop controls, observe instruments, etc. A broad platform shall be fitted over center engine, above which a hinged wood and metal ladder shall give access to the engine room hatchway above. Grab rails shall be placed on deck beams and coamings, also head bumpers on critical areas, to suit arrangement.

W-1-n. Lazarette.-The after peak shall be accessible through a hinged deck hatch with metal ladder to floor, and through a watertight door in after bulkhead of engine room. Lazarette -flooring shall be of slatted type giving full access to all parts of bilges. Stowage shelves of fir plywood, with deep ledges shall be substantially fitted for engine spares and boat stores. (For ammunition stowage in lazarette see section W-1-j.)

Emergency tiller shall be of steel tubing, demountably fitted to cast socket on center line tiller, and stowed conveniently in lazarette. Tiller socket shall be protected by antifouling box forward of rudder shelf. Means shall be provided for easy operation of emergency hand tillers.

Workbench shall be constructed and installed on forward side of transom in lazarette.


Joiner bulkheads and partitions shall be of plywood, mahogany or birch, properly stiffened, and framed at doors, or other apertures. To constitute structural reinforcement wherever possible, in which case, edges shall have special rabbetted stanchion at edges, with brackets to deck, bulkheads, or girders as required. Interior trim of mahogany limited to surfaces subject to much handling.


Grab rails as per plan shall be of wood or brass pipe in bronze stanchions. Special grabs shall be fitted at ladders, companionways, hatches, and elsewhere throughout ship as required for safe passage on deck or below.

Machine gun limiting stops of brass or steel tubing shall be fitted as required to prevent accidental firing into ship or occupants of bridge (see section A-5).


Welded steel towing pad and eye, hot dipped, galvanized, shall be fastened to the stem with inside blocking and brackets as required, complete with bridle and release mechanism and pendant for high speed towing.

The hawse pipe shall be of cast bronze and combined with bow light, and with eye fin for life lines and antenna mast stay to be fitted at stem head, with flanges to guard, and good deck pad, through bolted to breast hook.

One bow towing bitt, two forward fueling-at-sea bitts, two after towing bitts and 4 warping cleats shall be provided. A rope deck pipe of brass shall be located above chain locker. (See forepeaksection W-1.)


Life lines shall be as installed on Motor Torpedo Boat PT486 class, including removable stanchions and galvanized wire rope forward, and all necessary pins, lashings, turnbuckles, and chain plates; and fixed tubular stanchions well braced across stern with galvanized wire rope with turnbuckles, eyebolts, etc., as required.


Chafing, and cradle location plates, of aluminum or corrosion resisting steel shall be fitted at designated locations, in way of 20 chocks, and elsewhere as required. Kick plates of aluminum shall be fitted at doorways, behind ladders, etc., as required.


Suitable center line marking plates shall be installed together with all necessary labeling and stenciling as required by the Supervisor of Shipbuilding.


A canvas cover shall be provided for 20-mm. machine gun. Two canvas covers shall be provided for .50 cal. machine gun mounts to completely enclose guns, mounts, and limiting stops. After turret to have separate spray shield to height of limiting stop.

All covers shall be fitted with proper lashings.

All canvas covers and life preservers to receive approved treatment for fire retardance.

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