46 C.F.R. § 144.510

On a vessel of 65 feet (19.8 meters) or less in length, a window or windshield of sufficient size and proper accessibility may be used as one of the required means of escape from an enclosed space, provided it:

(a) Does not lead directly overboard;

(b) Is suitably marked; and

(c) Has a means to open the window or break the glass.