(a) For the purpose of this subpart, a type A vessel has—

1. (1) No cargo ports or similar sideshell openings below the freeboard deck;
2. (2) Only small freeboard deck openings fitted with watertight gasketed hatch covers of steel;
3. (3) No dimension of a freeboard deck cargo opening greater than 6 feet and the total area not exceeding 18 ft ²; and
4. (4) No more than two freeboard deck cargo openings to a single cargo space.