Code of Federal Regulations Title 33. Navigation and Navigable Waters § 33.401.46 Attending lines

(a) Lines of a vessel shall be under visual control and attended by members of its crew during the time the vessel is passing through a lock.

(b) While a vessel is within a lock chamber and lines are hand held for tension control, each line shall be attended by at least one member of the vessel's crew.

(c) Mooring lines on deck must be individually attended unless the vessel is equipped with side control and visual contact must be maintained for signal from lock employees taking or letting go of mooring lines.