LOCATION AND DESCRIPTION OF MAJOR COMPONENTS
Major components and equipment features of the IRB-R and IRB-I are identified and described below.
Locate the desired component by matching its description callout with the corresponding illustration
callout on the opposite page.
RAMP BAY EQUIPMENT FEATURES:
OUTER PONTON A non-compartmentalized structure that functions as a float to support loads
placed on its top (walkway) surface, and provides additional bouyancy to the inner ponton. The outer
ponton contains a stowage compartment for equipment and tools. Left and right outer pontons are not
STOWAGE COMPARTMENT A compartment in each outer ponton (ramp bay only) between the
walkway and splash plate for holding the Basic Issue Items (BII) necessary for IRB operation. The
following items and BII items can be stowed on the ramp bay:
Two ropes for securing bay
Two hand levers for operation of pumps
IRB hoisting gear (lifting sling) for high-bank launch
Spare Chem-lite tubes
Roadway tool for closing gap between inner-to-inner pontons
Crowbar for use with roadway tool
19-mm wrench for removing ponton drain plugs
Coupling device for bay-to-bay connection
RAMP PLATES The two plates mounted on the outer pontons used to increase the width of the
roadway approach ramp.
ROADWAY The top road surface of two adjoining inner pontons having a 13 ft 6 in. (4.1 m) wide
load bearing area for vehicles and cargo.
INNER PONTON A non-compartmentalized structure that functions as a float to support loads
placed on its top (roadway) surface. The inner ponton contains a pump and cylinder. Left and right
inner pontons are not interchangeable.
WALKWAY The 4 ft 3 in. (1.3 m) wide top surface of the outer ponton for personnel crossing.
HANDRAIL A retractable railing, extending the full length of the bay, consisting of two stanchions
and a cable mounted on each outer ponton splash plate.
UNFOLDING MECHANISM A system of cables, levers, and torsion bars located at the rear of the
IRB-R, that automatically control the unfolding of the inner and outer pontons once the bay is
launched. During retrieval, this mechanism works in reverse by pulling the outer pontons up into the
folded position simultaneously, as the entire bay is lifted from the water via the transporter.
RAISING MECHANISM The pump, cylinder, and yoke assembly, contained on each of the two
inner pontons, used for raising and lowering the ramp bay.