46 CFR 137.322: Classed vessels.

(a) A drydock and internal structural examination performed for a towing vessel to maintain class by the American Bureau of Shipping in accordance with their rules, as appropriate for the intended service and routes, would count as an examination required under § 137.300.

(b) A drydock and internal structural examination performed for a towing vessel to maintain class by a recognized classification society in accordance with their rules, as appropriate for the intended service and routes, would count as an examination required under § 137.300, provided the Coast Guard has accepted their applicable rules.