1A1. General. In many respects, the United
States Submarine Service is the most exacting of all the services in our armed forces.
The physical requirements for its personnel
are of necessity rigid. In order to maintain
these high physical standards, and for other
reasons, it is necessary that working and living conditions aboard submarines be the best
possible. The food must be not only the finest,
but it must be preserved in the best way.
Agreeable living conditions and wholesome
food go a long way toward maintaining the
health and morale of the entire personnel at
1A2. Preservation of food. Certain kinds of
food, such as meat and dairy products, deteriorate rapidly at ordinary temperatures.
They can be preserved only at low temperatures. Refrigeration prevents, or at least retards, the formation of molds and the growth
of bacteria and other microorganisms that
cause the spoilage of stored food. Obviously,
the length of time that a submarine can remain at sea is controlled to some extent by the
length of time that perishable foods necessary
for normal diet can be preserved by means of
1A3. Palatability of foods and beverages
at low temperatures. It is not sufficient that
foods be nutritious and in good condition to
be fully enjoyed. They must also be palatable.
Some foods and beverages are more palatable
when consumed in a chilled condition. Tepid
drinking water supplies the human body with
needed moisture equally as well as cold water,
but it is hardly refreshing in hot weather.
Who can enjoy the sticky sweetness of melted
ice cream? Refrigeration thus increases the
enjoyment of certain foods.
1A4. Air-conditioning and ventilation. Of as
great importance as the foods a sailor eats is
the air he breathes. The air on board ship, as
well as the foods, often needs to be cooled.
Moreover, during long dives, the air in submarines is used over and over again, and
therefore requires proper conditioning.
1A5. Protection of equipment. Too much
moisture in the air may interfere with the
proper operation of electrical equipment. It
is therefore necessary to prevent moisture
from condensing on such equipment.
1B1. Coldness and heat are relative terms.
Strictly speaking, coldness is not a distinct
condition separate from hotness. The two
terms are purely relative, without exact meanings. They merely express temperature conditions with reference to a standard. This
standard usually is the temperature of the
human body, which is normally 98.6 degrees
Fahrenheit. If a person picks up a piece of
ice, he says the ice is cold; he means that its
temperature is lower than the temperature of
his hand. If he drinks a cup of coffee, he says
the coffee is hot; he means merely that its
temperature is higher than that of his mouth.
Nevertheless, the ice is warmer than liquid
air, for example, and the coffee is cooler than
In discussing matters pertaining to refrigeration and air-conditioning, often it is
preferable to use the expression cooling,
rather than the awkward expression removing
heat. After all, refrigeration and air-conditioning deal with the maintenance of conditions best suited to the health and comfort
of the human body, and are concerned with
temperatures that human beings refer to in
ordinary usage as cool and hot. In this manual,
when cooling is used, it is understood that
the operation actually consists of removing