pressures to be carried at the various parts of the
Therefore, the amount of time that the ships are
lubricating system differ with the type of installation.
available for operations has been increased
For the latest information concerning F-76,
characteristics, handling, and testing, consult current
Hydraulic systems work on the principle that
technical manuals, instructions, directives, and notices,
liquids are noncompressible. Therefore, pressure or
along with NSTM, chapter 541.
force exerted at any point on an enclosed liquid is
transmitted equally in all directions. Hydraulic systems
All fuel oil comes from petroleum. Crude
operate remote control valves for flooding,
petroleum consists of a number of different
counter-flooding, and ballasting. Other examples of the
hydrocarbons-that is, compounds of hydrogen and
transmission of power aboard ship by hydraulics are the
carbon. Crude petroleum quite often contains traces of
operation of the steering gear, small hydraulic presses
in the shop, and hydraulically operated pipe benders.
Fuel oil itself is nonexplosive, difficult to ignite in
The design and arrangement of the cylinders, pistons,
bulk, and not capable of spontaneous combustion. Its
pumps, reservoir fluid tanks, and piping that make up a
vapors, however, form an explosive mixture with the
hydraulic system permit a great deal of work with little
oxygen in the atmosphere. The vapor is heavier than
effort on the part of shipboard personnel.
air and tends to collect in bilges and tank bottoms. Fuel
A satisfactory liquid for a particular hydraulic
oil vapor is always present in partially filed tanks or
installation must have chemical stability, freedom from
empty tanks from which the vapor has not been
acidity, lubricating power, rust inhibiting qualities, a
removed. Since this vapor is highly flammable, safety
high flash point, a pour point well below minimum
precautions must be continuously observed to prevent
operating temperature, and a high viscosity index. If a
a fire or explosion.
hydraulic fluid did not possess chemical stability,
The fuel oil system is arranged to allow the transfer
operating the system for considerable periods at high
of fuel oil from fueling connections to storage tanks,
temperatures would result in the formation of sludges,
from storage tanks to service tanks, and from service
gums, and carbon deposits. These deposits, in turn,
tanks to the burners at the boiler. It also allows the
would clog openings, cause valves and pistons to stick
transfer of fuel oil from one storage tank to another.
or leak, and give poor lubrication to the moving parts.
These transfers are made with pumps, manifolds, and
In petroleum-based fluids, chemical stability is
sometimes sluice valves, which permit gravity flow
improved by the use of chemicals called additives or
from one storage tank to another.
inhibitors. Such chemicals are also used to attain
The filling and transfer system usually consists of
freedom from acidity, improve lubricating power,
two large lines, one on each side of the ship, running
improve the viscosity index, and lower the pour point.
forward and aft. Cross-connections join these mains to
A satisfactory fluid for a given hydraulic system
the fuel oil booster and transfer pumps. Risers are
must have enough body to give a good seat at pumps,
provided fore and aft for taking on or delivering fuel.
valves, and pistons; but must not be so thick that it offers
The fuel oil service system consists of a service
main, manifolds, fuel oil service pumps, meters,
viscosity of the fluid must be suitable for the system in
heaters, strainers, burner manifolds, the burner lines,
and the burners at the boiler fronts.
The medium used to transmit and distribute forces
in hydraulic systems may be a petroleum-base product
LUBRICATING OIL SYSTEMS
(hydraulic oil) or the recently approved pure phosphate
ester fluid. Phosphate ester fluid is more fire resistant
The lubricating oil system supplies clean, cool oil
and explosion resistant than the petroleum-base oil used
to machinery bearing surfaces. Lube oil is routed from
exclusively in hydraulic systems for many years.
the filling connection to the storage or sump tank
Phosphate ester fluid is now used in aircraft carrier
located within the engine room. From this tank it is
elevators, surface ship missile systems, jet blast
pumped through a series of strainers and coolers to the
deflectors, seaplane servicing booms, high-pressure
bearing surfaces. Used oil is routed to a settling tank,
submarine systems, and for all new construction and
then through purifiers, and back to the sump tank. The
conversion surface ships in which the hydraulic systems