33 CFR 401.40 - Entering, exiting or position in lock.
(a) Unless directed by the Manager and the Corporation, no vessel shall proceed into a lock in such a manner that the stem passes the stop symbol on the lock wall nearest the closed gates.
(b) On being cast off in a lock, no vessel shall be allowed to fall back in such a manner that the stern passes the stop symbol on the lock wall nearest the closed gates.
(c) Every vessel proceeding into a lock shall be positioned and moored as directed by the officer in charge of the mooring operation.
(d) No vessel shall use thrusters when passing a lock gate.