Section 169.607 - Keel cooler installations(a) Except as provided in this section, keel cooler installations must meet the requirements of § 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 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 nonmetallic flexible hose may be used at machinery connections fixed by hose clamps provided that-(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 clamps are used on each end of the hose or one hose clamp is used and the pipe ends are expanded or beaded to provide a positive stop against hose slippage.