Section 15.840 - Able seamen(a) With certain exceptions, 46 U.S.C. 8702 applies to all vessels of at least 100 GRT. At least 65 percent of the deck crew of these vessels, excluding individuals serving as officers, must be able seamen. For vessels permitted to maintain a two-watch system, the percentage of able seamen may be reduced to 50 percent.(b) Able seamen are rated as: unlimited, limited, special, offshore supply vessel (OSV), sail, and fishing industry, under the provisions of part 12 of this subchapter. 46 U.S.C. 7312 specifies the categories of able seamen (i.e., unlimited, limited, etc.) necessary to meet the requirements of 46 U.S.C. 8702 .(c) On vessels subject to STCW, the individual meeting the requirement of this section must also hold an STCW endorsement as ratings forming part of a navigational watch or able seafarer-deck (according to § 15.404(a) and (b) of this part), except as noted in § 15.105 (g) of this part for vessels on domestic near-coastal voyages.(d) It is the responsibility of the master or person in charge (PIC) to ensure that the able seamen in the service of the vessel meet the requirements of 46 U.S.C. 7312 and 8702.CGD 81-059, 52 FR 38652, Oct. 16, 1987, as amended by USCG-2006-24371, 74 FR 11263 , Mar. 16, 2009; USCG-2004-17914, 78 FR 78008 , Dec. 24, 2013