which may be immediately commanded by the
MAINTENANCE
autopilot. The desired heading command is set
manually into the autopilot where it is compared with
The most common cause of failure of any hydraulic
system is dirt. Because hydraulic system clearances
the actual ship heading to produce the automatic rudder
are so precise, any amount of dirt or sludge introduced
commands.
into the system will eventually lead to problems in
HAND ELECTRIC MODE.-- Steering of the Ship
operation. A differential pressure indicator is
is controlled manually by the use of the helm wheel or
mounted across a hydraulic filter in the servo system
the controls on the ASCU or the PSCU.
in the auxiliary pump discharge. Replace the filter
element if the pressure drop across the filter exceeds
EMERGENCY MODE.-- In the emergency
12 psig. If fluid flow is impeded, a red indicator rod
steering mode, steering control is accomplished in the
rises from the differential pressure unit to visually
steering gear room in response to rudder commands
warn personnel of the degree of filter blockage. If
communicated by RAO indicators or orally over the
the red indicator rises, the filter element should be
ship interior communications system. The ASCU
replaced. The filter element should be replaced every
operates in the hand electric mode and transmits rudder
3 months, regardless of the pressure drop across the
commands through the steering control switchboard to
filter.
the rudder command servo units.
SUMMARY
If the ASCU becomes inoperable, the trick wheels
are used to send rudder commands to the command
Steering is an essential element of any ship. To keep
servo units manual] y and thus position the rudders.
steering dependable under all service conditions, you
MANUAL STEERING MODE.-- M a n u a l
must maintain and operate the steering gear and
hydraulic operation of the steering gear rams is affected
associated equipment according to posted instructions
by positioning the appropriate hydraulic valves and
and manuals.
hand cranking the emergency steering fill and drain
hand pumps as described below.
ELECTRIC GALLEY
EQUIPMENT
Manual positioning of the rudder is made
possible by hand operation of the emergency
Electric galley equipment comprises the heavy-duty
steering/fall and drain pumps. An emergency
rooking and baking equipment installed aboard naval
hydraulic system consists of hand pumps, a
vessels. This equipment consists essential y of ranges,
hydraulic oil storage tank, and valves and piping
griddles, deep fat fryers, roasting ovens, and baking
interconnected to the hydraulic steering system.
ovens. Electric galley equipment is supplemented by
When properly lined up, hydraulic fluid is
electric pantry equipment, which includes coffee urns,
applied to the ram cylinders to drive the rudders
coffee makers, griddles, hotplates, and toasters. The
to the desired position.
number and capacity of the units comprising a galley
installation depends on the size and type of ship. Galley
Hand pumps are operated by the normally
equipment is normally designed for operating on
stowed 15-inch handles. Either low or high
115-volt or 230-volt ac/dc or for operation on 115-volt
volume fluid flow may be selected by
or 230-volt ac/dc or 440-volt, three-phase, 60-hertz, ac
appropriately positioning a gear selector lever
power.
located on the hand pumps. Pressure relief
valves control system pressure at 650 psi.
RANGES
The hydraulic oil storage tank provides a
93-gallon capacity for operation of the
Electric galley ranges are provided in type A (36
emergency (manual) steering hydraulic system.
inch), type B (20 inch), and type C (30 inch). The ranges
Normal operating level (system lines full) is
consist of a range-top section and an oven section
maintained at 31 gallons. High-level caution is
assembled as a single unit and a separate switchbox
designed for overhead or bulkhead mounting. Figure
monitored at 82 gallons. In addition to the
emergency steering function, stored hydraulic
5-43 shows a type-A range. This range is provided with
fluid may be used to add makeup oil to the
three 6-kilowatt surface units and an oven section with
steering gear hydraulic ram cylinders.
two 3-kilowatt enclosed heating units.
5-64
