(a) In general
The Under Secretary may prescribe regulations relating to shore leave for professional mariners without regard to the requirements of section 6305 of title 5.

(b) Requirements
The regulations prescribed under subsection (a) shall—

(1) require that a professional mariner serving aboard an ocean-going vessel be granted a leave of absence of 4 days per pay period; and

(2) provide that a professional mariner serving in a temporary promotion position aboard a vessel may be paid the difference between such mariner's temporary and permanent rates of pay for leave accrued while serving in the temporary promotion position.

(c) Professional mariner defined
In this section, the term "professional mariner" means an individual employed on a vessel of the Administration who has the necessary expertise to serve in the engineering, deck, steward, electronic technician, or survey department.