46 U.S.C. § 7301: General

(a) In this chapter—(1) “service on deck” means service in the deck department in work related to the work usually performed on board vessels by able seamen and may include service on fishing, fish processing, fish tender vessels and on public vessels of the United States; (2) 360 days is equal to one year’s service; and (3) a day is equal to 8 hours of labor or duty. (b) The Secretary may prescribe regulations to carry out this chapter.