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The water for all these operations is either carried by the vessel or is distilled on board. The purpose of the water system is to store, distill, and distribute water to the equipment requiring it. (See Figure A-8.)

The fresh water tanks are connected by means of the fresh water filling and transfer lines. Supply branches connect to the three emergency tanks, lavatories, sinks, showers, scuttlebutts, galley equipment, distilling
Figure 9-1. Ship's fresh water filling valve.

Two 60-gallon emergency fresh water tanks are located on the port side in the forward torpedo room. One 130-gallon emergency fresh water tank is located on the port side in the after torpedo room. These tanks are connected to the fresh water system, while the 18-gallon emergency fresh water tank in the control room, and the 8-gallon emergency fresh water tank in the maneuvering room have no connections to the fresh water systems.

The fresh water filling valve and hose connection (Figure 9-1), located in the gun access hatch, connects with the fresh water filling and transfer lines extending to the forward and after ends of the vessel. In the forward torpedo room, the fresh water main has connections to the No. 1 and No. 2 fresh water tanks. It also has connections to the two 60-gallon emergency fresh water tanks, the crew's lavatory, and the torpedo filling connections. The 60-gallon emergency fresh water tanks are equipped with their own torpedo filling connections. The quantity of water in the No. 1 and No. 2 fresh water tanks is measured by try cocks located on the after bulkhead of the forward torpedo room. (See Figure 9-2.)

In the officers' quarters, the fresh water main supplies fresh water to the officers' pantry, the shower, the lavatories, and the hot water heater.

In the crew's quarters, the fresh water supply connections are to the galley equipment, scuttlebutt, scullery sink, and coffee urn. In the after end of the crew's quarters, the fresh water main supplies water to the two lavatories, showers, and the hot water heater.

The water main in the forward engine room is equipped with valves and connections to the distilling plants, and to the forward engine cooling system and purifiers.

In the after engine room the fresh water main is equipped with valves and connections

There are no fresh water connections in the maneuvering room. The fresh water main aft terminates in the after torpedo room where it supplies water to the emergency fresh water tank, the after torpedo filling connection, and crew's lavatory. The emergency fresh water tank is equipped with its own after torpedo filling connection.

9B2. Hot water system. Water for washing and cooking is heated by electric heaters. There are three electric hot water heaters. One heater with a 20-gallon tank is located in the starboard after corner of the control room; two heaters each with 25-gallon tanks are located one in the starboard forward corner of the forward battery compartment, and the other in the port after corner of the after battery compartment. Each heating unit is supplied with cold water from the fresh water mains.

The purpose of the battery water system is to store and supply distilled water to the forward and after batteries.

9C2. Description and operation. The battery water system consists essentially of two groups of four tanks each, filling and transfer lines, and valves and branch piping with hose connections for filling the individual battery cells. The four forward battery water tanks, Nos. 1, 2, 3, and 4, are located below deck in the forward battery compartment and are arranged in tandem, two on the port side and two on the starboard. The after battery water tanks are arranged similarly to the

The battery cells are filled by means of a hose which is attached to the battery filling connection, located on the battery filling line connecting the port and starboard tanks. The tanks are so interconnected that any one of the tanks can be used to supply the cells in either of the two battery compartments. Each of the two pairs of starboard and two pairs of port tanks is equipped with capacity gages accessible from the battery spaces.

9D2. Coffee urn. The crew's mess room is provided with a 5-gallon electrically heated coffee urn with a tap for drawing coffee in the mess room. A cold water line supplies the urn with water.

9D3. Scuttlebutt. The main drinking water dispensing equipment aboard the submarine is the scuttlebutt, or the drinking fountain. One scuttlebutt is located in the officers' pantry, and one in the crew's mess room. Each scuttlebutt is provided with a cold water supply line and drain to the sanitary tank drainage system. Before the water enters the scuttlebutt in the mess room, it is passed

9D4. Lavatories and showers. Each lavatory is provided with one cold water line, a hot water line, and a drain to the sanitary tank. There is one lavatory in the forward torpedo room, two in the officers' quarters, one in the commanding officer's stateroom, one in the chief petty officers' quarters, two in the crew's quarters, and one in the after torpedo room.

The showers are provided with hot and cold water. The deck drain for each shower is connected with the sanitary tank drainage system. There is one shower in the starboard forward corner of the officers' quarters and two showers in the after end of the crew's quarters.

The No. 2 sanitary tank, located in the after starboard end in the after battery compartment, receives the drainage from the sanitary drain which collects the discharge from the following: the galley sink, the scullery sink, the scuttlebutt, the crew's lavatories, the shower, and the washroom decks. The officers' head in the forward torpedo room empties directly into the No. 1 sanitary tank; the after head in the crew's quarters empties into the No. 2 sanitary tank. The forward head in the crew's quarters and the head in the maneuvering room discharge directly to the sea.

Figure 9-3. Expulsion type head.

The water closet installation consists of a toilet bowl over an expulsion chamber with a lever and pedal controlled flapper valve between, which is weighted to hold water in the toilet bowl and seats with pressure of the expulsion chamber.

Each installation operates as a separate unit with its own flood, blow, and discharge lines. The toilet bowl is provided with a sea flood with stop and sea valves. The expulsion chamber has a discharge line with swing check, gate, and plug cock valves. The blow line to the expulsion chamber receives air through a special rocker valve which, when rocked in one direction, admits air from the low-pressure air service line into a small volume tank until a pressure of approximately 10 pounds above sea pressure is reached. When rocked in the opposite direction, the rocker valve directs the volume of air into the expulsion chamber. A sea pressure gage, a volume tank pressure gage, and an instruction plate are conveniently located.

Before using a water closet, first inspect the installation. All valves should have been left shut. Operate the bowl flapper valve to ascertain that the expulsion chamber is empty.

Figure 9-4. Gravity flush type head.

If, upon first inspection, the expulsion chamber is found flooded, discharge the contents overboard before using the toilet. Improper operation of toilet valves should be corrected and leaky valves overhauled at the first opportunity.

9F2. Gravity flush type head. There are two gravity flush type water closets (heads), one in the forward torpedo room for the officers, and one in the after end of the crew's quarters. (See Figure 9-4.)

The water closet installation consists of a toilet bowl over a waste receiver with a lever and pedal-controlled flapper valve between, which is weighted to hold water in the toilet bowl and seats with the pressure in the tank.

Each toilet bowl is provided with a flood line with stop and sea valves. The water closets are located over the sanitary tanks and discharge directly into them.

Before using a water closet, first inspect the installation. All valves should have been left shut. Operate the bowl flapper valve to ascertain that the waste receiver is empty. Shut the bowl flapper valve, flood the bowl with sea water through the sea and stop valves, and then shut both valves. After using the toilet, operate the flapper valve to empty the contents of the bowl into the waste receiver and sanitary tank.

9G3. Fresh water stowage capacity. The normal fresh water stowage capacity is about 5400 gallons; 1200 gallons of this is battery water and is stored in the battery water tanks. This water will last only about 10 days and it is good practice not to allow the fresh water on hand to drop below one-half the normal capacity. The area of operations is usually the determining factor as to when the distillers can be used.

9G4. Principles of distilling action. The knowledge of distilling liquids comes from ancient days. Distillation is simply the boiling of a liquid and the condensing of its vapor to the liquid state again. In the boiling, much or all of any impurities or undesired contents are left behind, so that the condensed liquid is free of them. If a teaspoon is held in a cloud of steam arising from a teakettle, the vapor will condense on the spoon and the resulting liquid is distilled water.

9G5. The purifying action in distilling sea water. In sea water, salt and other substances are dissolved or held in solution. Sea water does not boil at the same temperature, 212 degrees F, as does fresh water, but at a temperature a few degrees higher. When the sea water boils, it is only the water (H2O) that is vaporizing at this temperature, and if that pure vapor is led to another clean container where it may condense, the result: is pure distilled water. The salt (sodium chloride) and other solid ingredients of the sea do not vaporize and hence do not come over into the distilled water.

9G6. Brief explanation. A brief explanation is given of the actions that take place in the Kleinschmidt still, without mentioning mechanical details, in order that these actions may be easily understood.

The distilling process in the Kleinschmidt still is continuous, with sea water being supplied at the rate of about a gallon per minute.

Part of the sea water flows out of the still as distilled water, and collects in the distillate tank. It can be transferred by blowing to the fresh water system or to the battery water system for stowage.

Figure 9.5. Kleinschmidt distillers.

The desuperheating tank, the purpose of which is to supply the cooling water to the still and to lubricate the lobes of the compressor at the top of the still, can be replenished from the distillate tank. The remaining sea water is concentrated brine and flows out separately.

Inside a cone-like casing, a long length of tubing is coiled. This casing is set with

9G7. Necessity of compressing the vapor. A question may arise as to why the vapor is compressed in the still. The explanation involves several considerations:

The conical crest of tubes serves three purposes: 1) vaporization of the feed water, 2) condensation of the vapor, and 3) cooling of the hot condensed liquid to a lower temperature. In the lower part of the nest, the feed water is at the temperature of sea water; the temperature increases during the upward flow, so that the feed water leaves the nest boiling. The feed water in the upper part of the nest is therefore very hot. On the downward flow, the vapor is condensed in the upper part of the nest, and in the lower part of the nest, the hot condensed liquid is cooled.

Sea water does not boil at the same temperature, for a given pressure, as does fresh water, but at several degrees higher. The feed water in the upper part of the nest is, therefore, actually above 212 degrees F. But the vapor from the boiling water is no longer sea water; it is fresh water vapor, and fresh water vapor at atmospheric pressure can condense only at 212 degrees F. When a vapor is compressed, its boiling point, or its condensation point, rises. By compressing the vapors in the still, its condensation point is raised above the temperature of the hot feed water in the upper part of the nest. Therefore, when the compressed vapor enters the nest, it finds a

9G8. Heat input of still. Compression of the vapor serves another purpose also. On starting operation of the still, the feed water is brought up to boiling temperature by the electric heaters. After the still is in normal operation, there will be a steady heat loss of definite amount through the insulation and in the outgoing condensate and brine overflow. This heat loss is balanced by an input of energy from the electric motor, which is transformed to heat by the compression of the vapor. Theoretically, this input of heat by the compressor maintains the heat balance at a constant level, and it is possible to operate the still with all electric heaters turned off. In actual practice, however, most of the heaters are usually left on after the still is in normal operation.

9G9. Vent to atmosphere. Since the boiling of the sea water takes place inside the shell of the still, it is necessary to prevent any increase of pressure on the boiling water, for increased pressure here would raise the boiling point and put the whole system out of balance and probably out of operation. The situation is different in the compressor; when the vapor goes into the compressor, it is sealed off from the boiling liquid and may then be compressed without affecting the boiling point. Therefore, in order that the boiling may always take place at atmospheric pressure as found within the submarine, a pipe called the vent leads from the vapor separator and out through the bottom of the still. This vent, being open to the atmosphere at its end, insures that the pressure in the vapor separator is always at the pressure of the surrounding atmosphere. A distant reading dial thermometer is connected by a flexible tubing to the vent to give the temperature in the vent pipe.

Although this open vent pipe leads downward out of the still, the steam when in normal amount inside will not flow out, because of the pressure of the outer atmosphere

The vent pipe also serves to permit drainage to the bilge of any slight amount of liquid carried into the vapor by the violent boiling action, and prevents it from gathering on the floor of the vapor separator. A small drain tube leading down from the compressor to just above the vent pipe in the vapor separator also permits water and oil to drain from the compressor seal out through the vent.

9G10. Portion of sea water not distilled. All of the incoming sea water cannot be distilled, for some must remain undistilled to carry away the concentrated salt content left from the distilled portion. This undistilled portion, which is concentrated brine, is maintained at a level just above the top coil of the heat exchanger by overflow pipes. It flows down through these overflow pipes into a separate conical passage, called the overflow heat exchanger, located around the nest of tubes, where it gives up some of its heat by conduction through the metal walls, thus helping to heat the incoming feed water.

9G11. Overflow weir cup. The overflow pipe, after leading out of the overflow heat exchanger at the bottom of the still casing, rises again a short distance. At the top of the upright overflow pipe, the brine flows out through an opening called the weir, which meters or measures the quantity of brine overflow in gallons per hour. The overflow brine passing out of the weir falls into an open cup and then drains down to a storage tank called the brine receiver, from which it is discharged to the sea.

Since water in any U-shaped container must always be at the same level in both arms of the U, the open weir is located at such a

9G12. Time required to start sea water boiling in still. When starting the still, from 60 to 90 minutes are required to bring the temperature up to the boiling point.

9G13. Heat balance in the still. It may be interesting to indicate the heat flow through

Figure 9-6. Distiller controls.

the various parts of the still in actual quantities. The following is an example:

Heat input: 10,185 Btu per hour come in through the compressor; 5,940 Btu per hour come in through the electric heaters. This is after the still is fully operating. The total input of heat is 16,125 Btu per hour.

1,825 Btu per hour in condensate, 11,600 Btu per hour in overflow, 400 Btu per hour from vent, 2,300 Btu per hour by radiation from hot metal parts, or a total heat loss of 16,125 Btu per hour. The heat balance is not always at this exact number of Btu per hour, for various momentary changes or rate of feed and temperature of sea water, voltage fluctuations in motor, or other operating conditions, will naturally cause it to vary around any average number. This heat balance of the still is very sensitive and all changes that may be necessary in the operation conditions should be made slowly.

9G14. Purity of the distilled water. If no leaks are present, the distilled water will contain only about one part of salt to a million parts of water. The distiller cannot, of course, remove any volatile liquids; that is, liquids that boil at or below the boiling temperature of water. For example, in badly polluted harbors or streams, a trace of ammonia may be present in the distilled water; and in improperly chlorinated waters, a trace of chlorine may likewise come over in the distilled water.

9G15. Two-still system. In the complete submarine distilling system, there are two

Two stills are necessary, not only as a safety factor, but also to provide sufficient distilled water. These stills may normally be run 300 to 350 operating hours without cleaning. Each gives 40 gallons per hour. This means a total of 24,000 to 28,000 gallons of distilled water. The consumption of distilled water is about 600 gallons per day for all purposes. On a war patrol lasting 60 days, the total consumption will be about 36,000 gallons, and may run higher in the tropics.

9G16. Water for the storage batteries. Distilled sea water is fit for human consumption and for the storage batteries. It may happen that fresh water is taken on board from some shore source. Such fresh water is not suitable for storage battery use until it has been distilled. Fresh water taken aboard in any foreign port should always be boiled or distilled before use. Only fresh water definitely known to be pure may be used without distilling or boiling for drinking, cooking, or personal use. In distilling fresh water that is taken aboard, the operation of the still is practically the same as when distilling sea water, the difference being that the overflow is returned to the ship's fresh water tanks from the brine tank instead of being discharged overboard.