the following: 3x7, 3x12, 4x7, 4x12, 5x12, 6x18, and
10x30 barges. The conventional pontoon barge, in sizes
up to and including the 6x18 barge, is designed to
carry its rated load with 1 of freeboard or a load
concentrated at the center point that is heavy enough
to bring the deck awash.
The 3x7 pontoon barge is a general-purpose
structure that can be used as necessary in lighterage
and ferrying operations. Cargo transport can be
accomplished by tow, or the barge can be self-propelled
by mounting a propulsion unit on the end without
fenders. A 3x7 barge with a propulsion unit is shown in
The 3x12 pontoon ramp barge is ordinarily used
for transporting cargo and equipment and has proved
suitable for general use in amphibious operation. The
sloping bow end with ramps attached permits beaching
the barge under its own power. And also it helps to
unload tractors and equipment that will be used to
assist in forming a causeway pier. Four 3x12 barges
can be side-loaded on an LST for side-carry to the
assault area, or the barges can be loaded in the well
deck of an LSD or deck-loaded on an LST.
The 4x7 pontoon barge is similar in all respects to
the 3x7 barge, except it is one string wider. Although
this is a general-purpose barge used principally for
lighterage operations, it is suitable for any
transportation task within its capacity.
The 4x12 pontoon barge is a general-purpose
structure that can be used in lighterage operations
either by towing or as a self-propelled structure by the
addition of propulsion.
The 5x12 pontoon barge is one string wider than
the 4x12 barge but similar in all other respects. It is
particularly suitable for mounting a crawler crane with
a lifting capacity ranging from 20 tons at a 12 radius
to 7 tons at 55'. This barge can also be used as a
general-purpose structure and can be used in
lighterage operations as a self-propelled structure by
the addition of propulsion units.
The 6x18 pontoon barge is the second largest
barge in the P-series pontoon system. Installation of
propulsion units permits its use in lighterage
operations for transporting loads (cargo, vehicles, and
personnel) up to 250 tons. By the addition of
accessories and equipment, the barge can be converted
into a 1,500-barrel fuel storage barge (fig. 10-28). Also,
by installing heavy-duty hinges, the barge can be
converted into a wharf or used for outfitting and repair
of smaller structures when placed on its deck.
The 10x30 pontoon barge is the largest barge in
the pontoon system. It was developed primarily for
mounting a 100-ton derrick (See fig. 10-29.) The barge,
however, is adaptable to other uses. With propulsion
units attached, it can serve as a lighterage barge in
transporting over 800 tons of cargo at one time from
ship to shore or dock. The barge can also be
Figure 10-27.A 3x7 pontoon barge with a propulsion unit.