Section 183.530 - Spud, pipe, and hose fitting configuration
Except when used for a tank fill line, each spud, pipe, or hose fitting used with hose clamps must have:
(a) A bead;(b) A flare; or(c) A series of annular grooves or serrations no less than 0.015 inches deep, except a continuous helical thread, knurl, or groove.
33 C.F.R. §183.530
CGD 74-209, 42 FR 5950, Jan. 31, 1977, as amended by USCG-1999-5832, 64 FR 34716, June 29, 1999