1A1. Importance of fresh water. Fresh water has
always been a major item aboard ship; in fact,
until comparatively recent times it has been the
factor that controlled the length of time a ship
could remain at sea. In the era of sailing ships,
it was necessary to spread canvas whenever it
rained, and to catch the rain water in canvas water
monkey bags in order to replenish the supply of
fresh water on board. This water was used only
for cooking and drinking purposes, there being
no need then for fresh water in the operation of
steam-driven propulsion machinery.
On modern naval vessels fresh water is of even
more importance, for it is used not only for cooking, drinking and bathing, but also in boilers, storage batteries, and as a cooling agent for modern
Diesel engines. All large naval vessels have distilling plants operated by steam, either high or
low pressure, which vary in capacity and type
with the size and class of ship.
1A2. Submarine sea water distillers. The first
successful apparatus for distilling sea water on
submarines was the Nelseco-Clarkson exhaust
evaporator installed about 1916. This evaporator
operated by using the exhaust from the main engines to heat the water to the boiling point, and
as the salt water boiled, the vapor was led to a
condenser where it condensed to fresh water.
Since the operating conditions of the engine varied, the heat value of exhaust gas available varied
accordingly, and hence it was almost impossible to
maintain a heat balance. The quantity and quality of the fresh water varied with the operating
conditions. The disadvantage of this evaporator
for submarine use was that it could be operated
only at full capacity when the submarine was running on the surface at high speeds. It could not
be used during periods of submergence.
During the period from 1937 to 1940 a vapor
compression type of distilling unit was developed
for use aboard submarines. Experiments on this
unit were conducted under actual operating conditions
on board the submarine U.S.S. S-20 at
New London, Connecticut, and resulted in the
development of the electrically operated Model S
vapor compression distilling unit which produces
750 gallons per day (gpd). These units were
installed on all new submarines and were used to
replace the Nelseco-Clarkson type on older
Further experiments with distilling units were
conducted by the manufacturer in coordination
with the Bureau of Ships and in 1943, the Model
X (1,000 and 2,000 gpd) vapor compression distilling unit was developed. The Model X-1
(1,000 gpd) distilling units were, for a number
of years, the only units to be installed on new
During the interval from that time until the
present (Jan. 1955), a number of improvements
and alterations have been made to the original
Model X-1 installations. The two-lobed compressors have been replaced with General Motors
three-lobed compressors. (Section 7B) The
original heat exchangers, in which there were three
small tubes inside of each larger tube, have been
replaced with the improved type described in this
text. The designation of the improved distilling
units was changed from Model X-1 to Model
In this text, frequent reference is made to the
Model X-1 distilling unit. It is to be understood,
unless specifically stated otherwise, that each reference applies also to the Model AAA-1 unit.
Further alterations have been made to adapt
the units to snorkeling conditions. It may be expected that the designation of these converted
units may be changed again.
There are also several newer models of distilling
plants undergoing service tests on some of the
later types of submarines. These new models will
be described briefly in Chapter 10.
1A3. Submarine distilling equipment. The distilling plants in use on submarines consist of: the
Kleinschmidt, Model S; the Badger Models X-1,
Y-1, V 1, WS-1, the Cleaver-Brooks 300 gpd, and
the Griscom-Russell 4,000 gpd Soloshell installed
on Nautilus. There are two (2) units of each applicable type installed on all of the later class
vessels except the SST's, the SSK's, and the SSN's
which have only one (1) unit. The Models are
described and illustrated separately.
1A4. Consumption of fresh water. A modern submarine consumes during a war patrol an average
of approximately 500 gallons per day of fresh
water for cooking, drinking, washing and engine
makeup water. In addition to this consumption
the main storage batteries require about 500 gallons of battery water per week; giving a total
requirement of at least 4,000 gallons per week.
These minimum requirements will leave enough
water for each man in the crew to have a bath at
least twice a week.
1A5. Fresh water stowage capacity. The normal
fresh water stowage capacity on most submarines
is about 5,600 gallons; of this, 1,200 gallons are
battery water and are stored in the battery water
tanks. This water will last only about ten days,
and it is good practice not to allow the fresh water
supply on hand to drop below one-half the normal
The operation of the submarine itself determines when the distilling plant should be used.
On some vessels, the auxiliary tanks are filled with
fresh water prior to leaving the tender or base.
This water is used for showers and washing of
clothes and supplements the normal capacity.
Small fresh water tanks are located in the forward and after compartments and contain emergency fresh water, but this supply is held in
reserve and is not normally used.