an air-driven hydraulic intensifier. Adjacent to the power
unit is a hydraulic fluid control valve panel. An
emergency air-hydraulic pump is also provided with the
system. Fluid pressure is transmitted to either the
undogging or dogging side of the hydraulic cylinders.
You must read the specific manufacturer’s manual or
NAVSEA 0916-LP-018-2010, Hydraulic Operated
Cargo Hatch Cover, to understand the full details of the
system. Along with this, you should trace the system in
your ship and complete the required PQS. During
repairs, follow the procedures specified by the PMS.
BOAT DAVITS
Gravity davits are found on most Navy ships.
Figures 8-1, 8-2, and 8-3 illustrate the types of gravity
davits that you will be maintaining.
For general information about boat davits, read
Boatswain's Mate, Volume 1, NAVEDTRA 10101. You,
as the maintenanceman, must also be familiar with the
proper operation of the boat davit. Some common
problems with the boat davit are rusting of parts, loss of
lubrication, contaminated oil in the gearcase, and faulty
centrifugal brakes. Because of the location of the boat
davit on the weather deck, the machinery is highly
exposed to sea spray, even though it is covered by
protective covering. You must lubricate the boat davit
and winch after adverse weather conditions. For
maintenance and repair of the boat davit, follow the
PMS assigned for this machinery. If your ship is
equipped with a double-pivoted link davit and a 50-hp
winch, NAVSHIPS 0920-072-1013 provides
information concerning maintenance instructions. Your
work center PMS Manual 43P1, under Maintenance
Index Page should provide you with the correct
reference publications for each piece of equipment.
BOW RAMP AND DOOR MACHINERY
The ramp and door system consists of the bow ramp,
bow doors, tracks, winches with their wire rope rigging,
fixed and positive guidance rollers, vangs, seating
device, pivot post, control consoles, various interlock
and limit switches, and the interlock control panels.
In time, repairs will become necessary to correct the
results of wear or to repair damage caused by various
casualty conditions. You must know and use the correct
sources of information necessary to efficiently
disassemble and reassemble the machinery. You must
Figure 8-1.—Trackway gravity davit.
8-10
