QSpaces not other-
M a i n p r o p u l s i on
spaces; pump, genera-
Fuel oil, diesel oil, and
lubricating oil tanks
Gasoline tank com-
Aircraft fuel stowage
Stowage of chemicals
and semisafe and dan-
gerous materials, ex-
cept oil and gasoline
Berthing and messing
spaces, medical and
dental areas, and
Stowage and handling
gasoline; void wing
water, including bilge,
sump, and peak tanks
Ships offices, laundry
rooms, galleys, pan-
tries, and wiring trunks
The double letters AA, FF, and GG identify
spaces used to carry cargo.
All ships require a means of propulsion. Navy
ships use four types of propulsion plants,
each with its own advantages and disadvan-
Conventional steam turbines
Nuclear power plants
CONVENTIONAL STEAM TURBINES
The substance that operates a conventional
steam turbine plant is steam. The plant produces
steam (generation phase) to drive the turbines
(expansion phase). It then condenses the steam
(condensation phase) and reuses it (feed phase)
to make steam again, as shown in figure 17-3.
One of the advantages of the steam propulsion
plant is that it is a high-power system with the
ability to propel combatant ships at high speeds.
Another advantage is that ships can use it for a
variety of auxiliary services, such as laundry and
galley operations and hot water heaters.
Disadvantages include its bulkiness and the
complication of the system. It is the slowest of
the plants used as far as preparations for
underway operations. Additionally, it consists of
a relatively large number of operating stations,
requiring higher manning.
Lets look at each of these four phases a little
Steam is generated in the boiler. Naval
propulsion boilers operate at 600 psi or 1,200 psi.
A pressure-temperature relationship exists in the
generation phase. At higher pressures, water must
be heated to a higher temperature before the water
will boil and produce steam. At 600 psi the boiling
temperature is 489°F. At 1,200 psi the boiling
temperature is 567°F.
In the pressure vessel of the boiler, steam
cannot be further heated unless all the water is
first boiled. Having some water in the boiler is
necessary to ensure heat flow and to prevent the
boiler tubes from melting.
As steam is drawn from the steam drum, it
first passes through separators to remove
moisture. It then passes through the superheater,
which further heats the steam to a higher tem-
perature. Superheated steam has more energy per
unit mass for conversion to mechanical energy.