(a) Except as prescribed in paragraph (b) of this section, access openings to double bottom tanks serving as dedicated ballast tanks must not be located within a cargo containment system.
(b) Each access opening to a double bottom tank that is a dedicated ballast tank and that is located within a cargo containment system must be:
(1) Enclosed in an access trunk extending to the weatherdeck;
(2) Separated from the cargo containment system by two manhole coverings; or
(3) Approved by the Commandant (CG-ENG).