33 CFR § 183.564 - Fuel tank fill system.
(a) Each fuel fill opening must be located so that a gasoline overflow of up to five gallons per minute for at least five seconds will not enter the boat when the boat is in its static floating position.
(b) Each hose in the tank fill system must be secured to a pipe, spud, or hose fitting by:
(1) A swaged sleeve;
(2) A sleeve and threaded insert; or
(3) Two adjacent metallic hose clamps that do not depend solely on the spring tension of the clamps for compressive force.
(c) Each hose clamp in the tank fill system must be used with a hose designed for clamps.
(d) Hose clamps used in the tank fill system must:
(1) Have a minimum nominal band width of at least one-half inch; and
(2) Be over the hose and the spud, pipe, or hose fitting.