Overhanging decks
12.—(1)  No portion of the top of a midship house or bridge deck, or the like, which is either always or occasionally used for purposes of navigation, is to be included in the measurement for passengers, and no portion of a bridge deck which extends beyond the sheer strake of the ship, nor any portion of a deck which extends beyond the sides or ends of a house or saloon, is to be so included.
(2)  Unless specially approved by the Surveyor-General of Ships no portion of a deck which is carried on stanchions only shall be measured, nor any deck which is supported by an extension of the ship’s frame above the upper deck, unless the frames are plated over so as to form a bridge house.