The application of the exemptions provided by section 13(a)(14) and section 13(b)(6) of the Act is determined in accordance with their language and scope as explained in §§ 783.24, 783.25, and 783.27, with regard to the principles set forth in § 783.20 and the legislative history and judicial construction outlined in §§ 783.28 through 783.30. Whether a particular employee is exempt depends on what he does, as explained in §§ 783.31 through 783.37. Whether he is exempt from the overtime pay provisions only or from minimum wages as well depends on whether his employment is or is not on an American vessel, which is determined as indicated in §§ 783.38 through 783.42. In addition, sections 13(a)(14) and 13(b)(6), like other exemptions in the Act, apply on a workweek basis as mentioned in § 783.43 and explained in §§ 783.49 and 783.50.