Well-decked ships
13.  In the case of well-decked ships, the deck spaces between the top gallant forecastle and raised quarter deck, bridge house, or poop, as the case may be, shall not be included, in the measurement for passengers, unless the deck is, in the opinion of a surveyor of ships, of sufficient height above the water, as indicated by the deepest subdivision draft to render it fit for their accommodation, and the freeing ports are fitted with suitable grids for the protection of the passengers, and children, and are in accordance with the following scale:
Length of Bulwarks in “Well” in Feet
Freeing Ports area on each side in Square Feet
15
8.0
20
8.5
25
9.0
30
9.5
35
10.0
40
10.5
45
11.0
50
11.5
55
12.0
60
12.5
65
13.0
Above 65, one square foot to each additional 5 feet length of bulwarks.