29 CFR 783.46: Hours worked.

The provisions of section 6(b)(2) of the Act require that a seaman employed on an American vessel be paid wages equal to compensation at not less than the prescribed minimum wage rate for all of the hours the employee “was actually on duty (including periods aboard ship when the employee was on watch or was, at the direction of a superior officer, performing work or standing by, but not including off-duty periods which are provided pursuant to the employment agreement)”. The Act in this portion of section 6(b)(2) is reflecting concepts that are well established in the law, and existing precedents (in such cases as Armour & Co. v. Wantock, 323 U.S. 126; Skidmore v. Swift & Co., 323 U.S. 134; Steiner v. Mitchell, 350 U.S. 247; Mitchell v. King Packing Co., 350 U.S. 260; Tennessee Coal, Iron & R. Co. v. Muscoda Local N. 123, 321 U.S. 590; and General Electric Co. v. Porter, 208 F. 2d 805, certiorari denied, 347 U.S. 951, 975) would be applicable in determining what time constitutes hours worked. See also the general discussion of hours worked in part 785 of this chapter.