Except those serving on vessels listed in §15.105(f) and (g) of this part, each master of a vessel that operates beyond the boundary line, as described in part 7 of this chapter, must ensure observance of the principles concerning watchkeeping set out in Regulation VIII/2 of the STCW Convention and section A-VIII/2 of the STCW Code (both incorporated by reference, see §15.103 of this part).