TM 5-1940-321-13&P
NOTE:
In some cases the location of the bubbles may not be the true location of the
leak. Air can travel under items such as lacing cuffs or rubbing strakes and
emerge some distance from the actual location of the leak. Air can also travel
between the layers making up the fabric and then emerge where there is a worn
spot on the fabric.
( 13 ) Brush the soap solution over all accessible areas of the buoyancy tubes and
keel. Visually inspect for bubbles that grow in size, indicating a leak. Use a
silver pen to mark the exact area where leaks are observed.
NOTE:
Very small leaks can be caused by fabric pinholes. Fabric pinhole leaks are often
present in areas where the fabric coating is worn. These leaks usually form many
very small bubbles over an area. The many small leaks through the fabric can
contribute to the craft failing the 24-hour pressure retention test. If the leaks
occur in specific areas, such as where the fabric is worn, circle the area with the
silver pen. Pinhole leaks over large areas are most often observed on older craft.
( 14) Turn the craft upside down. Brush the soap solution over all accessible areas.
( 15 ) Visually inspect for soap bubbles that grow in size, indicating a leak.
( 16 ) Carefully inspect the lower buoyancy tube hose fittings and hose areas which
were not accessible with the craft in the upright position. Mark the location of
any leaks using a silver pen.
( 17 ) After all leaks have been marked with the silver pen, rinse the soap away with
water.
( 18 ) The corrective maintenance action for various types of leaks is discussed in
6-4. WATER LEAK TEST. The water leak test is performed by unit maintenance personnel whenever
water accumulation in the craft floor indicates the possibility of leaks in the fabric hull bottom or in a self-
bailer. Obvious tears or punctures in the bottom fabric can be located without performing test. Leaks
between the bottom fabric and the transom require this test to properly identify the specific location of the
leak.
6-8
