46 CFR § 153.230 - Type I system.
A type I containment system must meet the following requirements:
(b) Except as described in § 153.235:
(1) It may be no closer to the tankship's shell than 76 cm (approx. 29.9 in.); and
(2) It may not be located in any part of the tankship subject to the damage described in Table 172.135 of this chapter for:
(i) Collision Penetration, Transverse extent; and
(ii) Grounding Penetration, Vertical extents from the baseline upward.