45.121—Freeing port area: Changes for trunks and side coamings.
         If a vessel has a trunk and does not meet the requirements of  § 45.61 or has continuous or substantially continuous hatchway side coamings between detached superstructures, the minimum area of the freeing port openings must be obtained from the following table:
    
    | Breadth of hatchway or trunk in relation to the breadth of ship | Area of freeing ports in relation to the total area of the bulwarks (percent) | 
|---|---|
| 40 percent or less | 20 | 
| 75 percent or more | 10 | 
The area of freeing ports at intermediate breadths must be obtained by linear interpolation.