33 CFR 401.37: Mooring at tie-up walls.

(a) Upon arrival at a lock, a vessel awaiting instructions to advance shall moor at the tie-up wall, close up to the designated limit or approach sign or to the ship preceding it, whichever is specified by the traffic controller or an officer.

(b) Crew members being put ashore on landing booms and handling mooring lines on tie-up walls shall wear approved personal flotation devices.

(c) Should the situation arise where a tie up at an approach wall is provided by Seaway personnel at the Canadian Locks, synthetic mooring lines should be used.