TM 55-1930-203-10
position for reverse operation. The engine speed is increased by continued advance of the marine controls, both ahead or reverse.
b. To disengage the propellers, place the marine gear control valves in neutral position.
2-40. Entering Water
a. General. The exact procedure to follow when entering the water must be determined by the operator. The following general
instructions are to be used as a guide:
b. Entering Over Sandy Beach.
(1) Stop the LARC a short distance before entering the water and shift the transmission to second gear if entering directly into
deep water. Use low gear if entering through shallows. Set steering for two-wheel steer.
(2) Advance the throttle slowly from idle until the desired entry speed is attained.
(3) Upon entry into the water and after the LARC is fully afloat, reduce engine speed to idle and shift the transmission to neutral
position.
(4) Advance the marine gear control valve levers to desired speed. Continued movement of the levers to desired speed.
Continued movement of the levers will increase the engine speeds from idle to full speed.
c. Entering Surf.
(1) Stop the LARC before reaching the edge of the water. Set steering for two-wheel steer, shift the transmission to first gear,
and engage the propellers.
(2) Head the LARC directly into any surf, breakers, tide, currents, or wind.
(3) Maintain a moderate to high (1000 to 1700 rpm) engine speed when entering the water, using only enough engine power to
hold heading into the surf line.
(4) When the LARC is fully afloat,-shift the transmission to neutral position and advance the marine gear control valve levers for
desired speed.
d. Entering Over a Steep Ledge. Under some conditions, such as descending steep grades or entering water over steep banks, it
is necessary to get the propellers into the water first to aid in launching the LARC. When entering the water stern first, proceed as
follows:
(1) Select the best possible approach to the water.
(2) Maneuver the LARC to enter the water at 90 to the shore line.
(3) Shut off radiator fans by lifting the radiator fan motor controls (30, sheet 4, fig. 2-1).
(4) Using the foot brake to maintain speed control, slowly maneuver the LARC into the water.
(5) As the stern enters the water, advance the marine control valve levers to full throttle as soon as the stern is afloat.
(6) When the LARC is fully afloat, reduce engine speed to idle and shift the transmission to neutral position.
(7) Clear all obstacles and swing the LARC around for desired heading.
e. Entering Over Coral or Sharp Rocks. Operate the LARC at very low speed with transmission in first gear position. Do not
engage
the propellers until the LARC is fully afloat. However, if heavy surf or strong current exists, stop the LARC before entering the
water and engage the propellers.
f. Entry Inspection. After the LARC is in the water, check for leakage. If there is excessive leaking indicated by an abnormal
quantity of water in the bilges, return to land as quickly as possible. If leaks are normal, operate the bilge or cargo well pumps as
necessary. Excessive bilge water may be caused by hull drain valves not being securely closed.
2-41. Operating in Water
CAUTION
Do not shift directly from forward to reverse or reverse to forward until oil pressure drops
off and restores.
a. Forward and Reverse Movement. Forward and reverse movements in water is accomplished by moving the marine gear
control valve (4, sheet 1, fig. 2-1) handle in the desired direction of travel. When the control valve handle is moved 10 to either side
of neutral, the marine gear engages. Further movements of the handle from the 10 position, away from neutral, increases the
engine speed from idle to full speed. To shift from forward to reverse or reverse to forward, proceed as follows:
(1) Place the marine gear controls in neutral position.
(2) As soon as the engine speeds drop below 900 r.p.m., move the controls 100 away from neutral in desired direction of travel.
This engages the marine gear while engines are at idle.
(3) Watch the marine gear oil pressure gages (14, sheet 1, fig. 2-1). The marine gear oil pressure will drop off and then be
restored.
(4) As soon as the marine gear oil pressure has been restored to 180-200 p.s.i., advance the controls to desired engine speed.
b. Steering. Use two wheel steer to reduce the drag of the wheels when steering by rudders. The use of two-wheel steer results in
better water speed and consistent maneuvering charac-
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