HULL ASSEMBLY REPAIR INSTRUCTIONS
The exact procedure to be followed in hull repair varies with the location of the damaged or
broken section. In the areas above the engine mounting surface and running from the back of
battery compartment to the transom there are buoyancy foam blocks that can be removed. In the
bow section buoyancy foam is placed and the deck riveted or welded in place. Below engine
mount level the space is filled with buoyancy balls. Buoyancy balls are plastic spheres of two
sizes which are 25/32 in (20mm) and 1-49/64 in (45mm) in diameter. For those two areas any
welding or heating done on the exterior surface must be done carefully to prevent excessive
damage to the buoyancy material. Refer to FO-4 for general arrangement of buoyancy materials.
Application of flame to buoyancy foam produces an acrid smoke. Inhalation of this smoke may be
harmful to personnel. Flame should not be allowed to come in contact with buoyancy foam. Care
in heating metal in contact with buoyancy foam must be exercised.
Use rubber-headed mallet with back-up mallet on
opposite side of the plate. Hammer carefully,
first around outer periphery and then work in a
spiral to center where dent is greatest.
Deep dents may require careful application of
heat to aid in reforming metal.
Use temperature-indicating crayon:
Mark central area of dent with 500°F
Mark rings around central area with 400°F
Apply heat until crayon marks begin to melt.
Withdraw heat and immediately start hammering.
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