46 CFR 15.840: Able Seafarers.

(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 Seafarers. For vessels permitted to maintain a two-watch system, the percentage of Able Seafarers may be reduced to 50 percent.

(b) Able Seafarers are rated as: Unlimited, Limited, Special, OSV, Sail, and Fishing Industry, under the provisions of part 12 of this subchapter. 46 U.S.C. 7312 specifies the categories of Able Seafarers (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 Rating Forming Part of a Navigational Watch (RFPNW) or Able Seafarer-Deck (according to § 15.404(a) and (b)), except as noted in § 15.105 (g) 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 Seafarers in the service of the vessel meet the requirements of 46 U.S.C. 7312 and 8702.