46 CFR §194.10-20

1. (a)Magazine chests shall be of watertight metal construction with flush interior. The body and lid shall have a minimum thickness of 1/8 inch.
2. (b)Permanent sun shields shall be provided for sides and top including the lid. These shall have a minimum thickness of 1/8-inch aluminum or 16-gage steel. Side shields shall be offset from the body a distance of 1 inch. The top shield shall be offset a distance of 1 1/2 inches. Sun shields may be omitted when chests are installed “on deck protected,” shielded from direct exposure to the sun.
3. (c)Chests shall be limited to a gross capacity of 100 cubic feet.
4. (d)Chests shall be secured to the vessel's structure by means of permanently installed foundation clips or bolts or a combination thereof. Lashings will not be acceptable.
5. (e)Chests shall be provided with substantial hasps and staples for locking purposes.