retreating army forces by crossing a river, thereby delaying the enemy's
advance. A line of defense is then established along the exit bank of the
river, which effectively forces the enemy to conduct a deliberate river
crossing to continue its assault. IRB equipment is used extensively in this
2. Site Requirements. Site selection is a critical step in performing a river
crossing, and the requirements are generally based on strategic planning and
equipment limitations. Crossing sites are generally characterized as assault,
rafting, or bridging, with each having its own set of requirements.
a. An assault site is selected for the following characteristics:
(1) Enemy forces are weak, the terrain on the friendly shore provides
concealment from enemy observation, and there is room for the assault
to be supported by overmatching fire.
(2) Adequate crossing routes exist to and from the river at its narrowest
point, and current velocity is 05 ft (01.5 m) per second.
(3) There are gently sloping, firm banks which permit rapid entry and exit
at multiple points along the river.
(4) Riverbank slopes and water depth do not exceed the specified limits for
the equipment entering the river.
b. All raft sites require the following characteristics:
Gravel and small rocks on roadway surface leading to
raft can cause dents and punctures in raft roadway
deck and can also become lodged in ramp and interior
bay unfolding mechanisms, causing jamming during
bay retrieval. If gravel or small rocks are present at raft
site, either remove them or cover them with topsoil or
(1) The site should be positioned downstream from a bridge site.
(2) The site should provide the fastest access to the far shore with
established road networks on both sides of the river.
(3) The site should be located at a narrow point along the river that is free
of sandbars or obstacles that would impede operations.
(4) The site should have firm banks on both sides with slopes, water depth,
and current velocity within the specified limits for the IRB launch
method used. (Refer to WP 0019, table 1, Launch Restrictions.)
SITE REQUIREMENTS AND LAYOUTS (Contd)