33 CFR 165.11: Vessel operating requirements (regulations).

Each District Commander may control vessel traffic in an area which is determined to have hazardous conditions, by issuing regulations:

(a) Specifying times of vessel entry, movement, or departure to, from, within, or through ports, harbors, or other waters;

(b) Establishing vessel size, speed, draft limitations, and operating conditions; and

(c) Restricting vessel operation, in a hazardous area or under hazardous conditions, to vessels which have particular operating characteristics or capabilities which are considered necessary for safe operation under the circumstances.