TM 55-1930-203-10
frequently to insure that the plates are fully covered with distilled water.
WARNING
Fuel oil and other similar materials are highly volatile in extreme hot weather and
these vaporizations create an explosion possibility. Wipe up all spilled petroleum
products. See that fuel lines and valves have no leaks. Pump the bilges regularly.
2-49. Operation in Sand, Mud, Coral, and Snow
a. General. The LARC will mire easily in soft ground. Therefore, investigate any unknown route. It will be extremely difficult to
free a mired LARC.
b. Sand and Snow. The most common type of terrain which must necessarily be crossed during amphibious operations is sand.
The operator must always be alert for conditions of terrain. If the LARC mires, the winch or some other means will be required to pull
it out. The same is true of operation in snow.
CAUTION
Do not deflate tires to less than 35 pounds.
(1) Tires will be inflated or deflated according to the consistency of the sand or snow.
(2) Select first or second speeds for deep sand or deep snow with a heavy load. First gear should be used if the sand or snow is
extremely soft and the LARC is heavily loaded.
(3) One of the most important phases of traveling over sand or snow is to lay wheel tracks over the terrain, not "dig in" the
wheels. Travel over the terrain with sufficient power and speed for normal traction.
(4) If the wheels are permitted to spin, they will immediately dig in. The instant progress stops, let up on the throttle. When the
LARC cannot progress over the sand or snow with sufficient speed, cut off the power, back up, and make another attempt at a higher
speed. This procedure may be necessary several times. If the LARC cannot go forward or backward without digging in, stop using
the wheels, and either winch out with the help of the wheels or get help from some other source.
(5) Always go up difficult sand or snow grades straight and square, never at an angle. When the wheels are turned sharply,
much of their forward driving action is lost, and the tendency to dig in is increased. There is also the added resistance of all wheels
making separate tracks. Pick the best spots for necessary turns, and make the turns as wide as possible. Approach difficult places
straight and fast. When the LARC travels over sharply rising sand dunes or snow drifts and there is a possibility of bottoming, keep
the LARC moving fast at a steady speed to prevent stradling on the crest.
(6) If more than one LARC is operating to and from the water over a sandy or snow-capped beach, the leading driver should pick
the best available path. The LARC's at the rear should follow in the leader's tracks. No attempt should be made to pull out or make
another track unless stalled LARC's ahead have made the roadway impassable. Do not follow too closely since the LARC ahead
may have to back up to make another forward attempt.
c. Soft Mud and Marshes. Avoid soft, sticky mud, marshes and swamps. Underwater mud has a gripping effect which generally
mires down any wheeled amphibian. Pick out another spot to land or to enter the water. Avoid traveling close to boggy banks or in
shallow water with a boggy bottom. Test the depth and consistency with a boat hook. If the LARC is in a boggy area, the operator
should use all wheels with transmission in the first or second gear.
d. Coral and Rocks. Tires must be operated under rough terrain conditions with an inflation pressure not to exceed 70 p.s.i. Drive
over such terrain at a very low speed. If there is a possibility of hidden coral heads, use first or second gear, or first gear only.
2-50. Operation on Three Wheels
In event of loss of a wheel or tire, the LARC can be operated on three wheels. In such emergency, perform the following:
a.
Close the tire air shutoff valve (2, fig. 2-2) to
wheel or
tire involved.
b. Move the cargo from the area of the wheel or tire involved and relocate to area of the wheel diagonally opposite.
c. Proceed slowly to destination.
2-51. Emergency Marine Steering
Under extremely adverse sea conditions, reduction in speed will minimize navigating problems created by waves. When landing in
surf, steer directly in front of waves and maintain full throttle to assure maximum steering control. If rudders are knocked off, or any
part of the linkage is broken or disconnected, or if the steering cable fails, the LARC can be steered by varying the speed of the port
and starboard engines. Steering forward can be accomplished to the port side by reducing the speed of the port engines and
increasing the speed of the starboard engines.
2-38