S.L. 646.2 ст. 15Hatch coverings.

All hatch coverings shall be kept plainly marked to indicate the deck and hatch to which they belong, and their position therein:

Provided that this regulation shall not apply in cases where all the hatch coverings of a ship are interchangeable or, in respect of marking of position, where all hatch coverings of a hatch are interchangeable. This regulation shall apply to fore and aft beams and to thwartship beams as it applies to hatch coverings.