46 CFR 78.47-37 - Watertight doors.
(a) All watertight doors in subdivision bulkheads shall be numbered conspicuously on both sides on an etched plate or equivalent in not less than 3/8 inch letters and figures “W. T. D. 1,” “2,” “3,” etc. If a stenciled or similar notice is used, the letters and figures shall be at least 1 inch high. If the construction is such that the number cannot be seen with the door in the open position, a similar number shall be placed on the frame or other location immediately adjacent to the door. All watertight door remote control stations shall be marked in the same manner, and in addition, the direction of operation of the lever or wheel to open and close the door shall be conspicuously marked.
(b) Class 1 doors fitted in accordance with the requirements in § 170.255 of this chapter must additionally be marked “RECLOSE AFTER USE.”