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. [CGD 74-209, 42 FR 5950, Jan. 31, 1977, as amended by USCG-1999-5832, 64 FR 34716, June 29, 1999]