Correction for superstructures and trunks.

(a) Where the effective length E of superstructures and trunks that meet the requirements of subpart D of this part is 1.0 L, the minimum summer freeboard may be corrected by subtracting 1/2 H s . (b) Where the effective length of superstructures and trunks is less than 1.0 L the minimum summer freeboard may be corrected by subtracting a percentage of one-half of the standard superstructure height ( H s ) determined by the formula: Percentage = ( E /2 L ) (1 + E / L ) × 100 (c) To be eligible for the correction a trunk must— (1) Be at least as strong and as stiff as a superstructure; (2) Have no opening in the freeboard deck in way of the trunk, except small access openings; (3) Have hatchway coamings and covers that meet §§ 45.143 through 45.147; (4) Provide a permanent working platform fore and aft with guardrails; (5) Provide fore and aft access between detached trunks and superstructures by permanent gangways; (6) Be at least 60 percent of the breadth of the ship in way of the trunk; and (7) Be at least 0.6 L in length, if no superstructure, is provided.