TM 5-1940-321-13&P
Section II.
OPERATION
4-4. PREPARING FOR OPERATION. The F530 IAB must be properly prepared before operation to
ensure full performance and safety. Appendix H contains forms used in performing a technical inspection
( TI ) Limited Technical Inspection ( LTI ).
CAUTION
Verify that the foot pumps, hoses, pressure gauge and repair kit are on
board before operating the F530 IAB.
a. Inflation Pressure. Refer to chapter 2, paragraph 2-2, for inflation procedures. Inflation
pressures must be correct. The correct pressure is 240-280 mb (3.5 to 4.1 psi) for the buoyancy tubes
and 220-240 mb (3.5 to 3.5 psi) for the inflatable keel. A pressure check is required daily during periods of
craft operation (see chapter 5, paragraph 5-7).
CAUTION
Do not operate a F530 IAB that is underinflated. Underinflation can result in
damage to the transom and thrustboard attachment systems, poor
performance, and reduced life of the F530 IAB. Check air pressure after one
hour, after large temperature changes, and regularly thereafter.
( 1 ) Temperature. A change of only 1.8F in temperature results in a 4 mb (.06 psi)
pressure change. Temperature increase cause air pressure increases. Temperature
decreases cause air pressure decreases A craft inflated on shore at an ambient
temperature of 80F and then placed in water with a temperature of 60F will lose
44.5 mb (.65 psi) of pressure. This pressure loss can be incorrectly attributed to air
chamber leaks. A craft inflated in the morning when it is cool will have increased
pressure as the temperature increases later in the day. Operators must be aware of
these pressure changes caused by temperature changes and check inflation
pressure regularly (see chapter 5, paragraph 5-7).
( 2 ) Pressure Stabilization. If pressure is checked on shore, it must be check again after
the craft is in the water. After initial inflation of a deflated or partially deflated craft,
the pressure must be allowed to stabilize for one hour and then checked again with
the pressure gauge as described in chapter 5, paragraph 5-7. The stabilization time
is necessary because the fabric that forms the air chambers stretches. A new craft
will experience more stretch than an older craft.
4-4
