46 CFR §32.70-25

Cargo tanks shall comply with the conditions specified in §§ 32.65-30 and 32.65-35, and shall pass the tests required in § 32.65-40: Provided, however, That less than 15 inches around such tanks may be accepted if in the judgment of the Officer in Charge, Marine Inspection, making the inspection, a satisfactory inspection of the cargo tanks and hull structure can be made.