46 C.F.R. § 172.050
(e) Each tank barge must be shown by design calculations to have at least 2 inches (50 mm) of positive GM in each condition of loading and operation after assuming the damage specified in paragraph (f) of this section is applied in the following locations:
(2) Type I barge hull in an integrated tow. If a Type I hull is required and the barge is a box barge designed for operation in an integrated tow, design calculations must show that the barge can survive damage—
(f) For the purpose of paragraph (e) of this section—
(2) Damage must consist of the most disabling penetration up to and including penetrations having the following dimensions:
(i) Side damage must be assumed to be as follows: