Every vessel of 1600 gross registered tons or integrated tug and barge or articulated tug and barge unit of combined 1600 gross registered tons or more equipped with a variable pitch propeller shall be equipped with-
33 C.F.R. §401.17
68 Stat. 93-96, 33 U.S.C. 981-990 , as amended and secs. 4 , 5 , 6 , 7 , 8 , 12 and 13 of sec. 2 of Pub. L. 95-474 , 92 Stat. 1471