Code of Federal Regulations Title 46. Shipping § 46.28.555 Freeing ports

(a) Except as provided in paragraph (i) of this section, each decked vessel fitted with bulwarks must be fitted with freeing ports.

(b) Freeing ports must be located to allow the rapid clearing of water in all probable conditions of list and trim.

(c) Except as provided by paragraphs (d) through (h) of this section, the aggregate clear area of freeing ports on each side of the vessel must not be less than 0.71 plus 0.035 times the length of the bulwark, in meters, for area in square meters, or 7.6 plus 0.115 times the length of the bulwark, in feet, for the area in square feet. The length of bulwark need not exceed 0.7 times the overall length of the vessel.

(d) Except as provided in paragraphs (e) through (h) of this section, for bulwarks which exceed 20.11 meters (66 feet) in length, the aggregate clear area of freeing ports on each side of the vessel must not be less than 0.07 times the length of the bulwark, in meters, for an area in square meters (0.23 times the length of the bulwark in feet, for an area in square feet). The length of the bulwark need not exceed 0.7 times the overall length of the vessel.

(e) For a bulwark more than 4 feet (1.22 meters) in height, the freeing port area required by paragraphs (c) or (d) of this section must be increased in accordance with the following formula:

i=[h–4]0.04q, (i=[h–1.722].04q, for metric units), where:

i=increase in freeing port area, in square feet (square meters);

h=bulwark height, in feet (meters);  and

q=length of bulwark exceeding 4 feet (1.22 meters) in height, in feet (meters).

(f) For a bulwark less than 3 feet (0.91 meters) in height, the required freeing port area, required by paragraph (c) or (d) of this section, may be decreased in accordance with the following formula:

r=[3–h]0.04q, (r=[h–0.91–h]0.04q), where:

r=permitted reduction in freeing port area, in square feet (square meters).

h=bulwark height, in feet (meters).

q=length of bulwark which is less than 3 feet (0.914 meters) in height, in feet (meters).

(g) For a vessel without sheer, the freeing port area must be increased by 50 percent.

(h) The area of the freeing ports on a vessel that operates on protected waters need only be 50 percent of the area required by paragraphs (c) or (d) of this section.

(i) Freeing port covers are permitted provided that the freeing port area required by this section is not diminished and the covers are constructed and fitted so that water will readily flow outboard but not inboard.