46 CFR § 154.305
Segregation of hold spaces from the sea
April 15, 2021
In vessels having cargo containment systems required by this part to have a secondary barrier, hold spaces must be segregated from the sea by:
(a) A double bottom if the cargo tanks meet this part for design temperatures colder than −10 °C (14 °F); and
(b) Wing tanks if the cargo tanks meet this part for design temperatures colder than −55 °C (−67 °F).