Section 128.420 - Keel cooler installations(a) Except as provided by this section, each keel cooler installation must comply with § 56.50-96 of this chapter.(b) Approved metallic flexible connections may be located below the deepest-load waterline if the system is a closed loop below the waterline and if its vent is located above the waterline.(c) Fillet welds may be used in the attachment of channels and half-round pipe sections to the bottom of the vessel.(d) Short lengths of approved non-metallic flexible hose fixed by metallic or non-metallic hose-clamps may be used at machinery connections if-(1) The clamps are of a corrosion-resistant material;(2) The clamps do not depend on spring tension for their holding power; and(3) Two of the clamps are used on each end of the hose, except that one clamp may be used on an end expanded or beaded to provide a positive stop against hose slippage.(4) The clamps are resistant to vibration, high temperature, and brittleness.CGD 82-004 and CGD 86-074, 62 FR 49331, Sept. 19, 1997, as amended by USCG-2000-7790, 65 FR 58463 , Sept. 29, 2000