33 CFR §401.47

1. (a)Mooring lines shall only be cast off as directed by the officer in charge of a mooring operation.
2. (b)No vessel shall proceed out of a lock until the exit gates, ship arresters and the bridge, if any, are in a fully open position and the lock operator gives the “all clear” instruction.
3. (c)When “Hands Free Mooring system (HFM) is used, no vessel shall use its engine(s) until the lock operator provides the “all clear” instruction.