Navigating the Inland Waterways: Locking Through | Quimby's Cruising Guide

Don’t let locks stop you. They aren’t just for commercial traffic — they’re for you, too, and there’s no charge for using them. By learning how to use the locks, you can increase your cruising range and extend your adventures.

All boats going through a lock should have at least 50 feet of line that can be used to moor the boat to the lock chamber wall or tossed up to the lock tender to secure at the top. Make sure you have fenders on the sides of your boat when you enter the chamber and have someone standing by to pay out or take in mooring line as the water level in the lock rises or falls.

St. Anthony Falls Lock & Dam

When approaching a lock, stay in the navigation channel as marked by the buoys. Be aware that some areas near locks and dams are dangerous and stay clear of those areas. Hold station about 400 feet from the end of the lock walls, in case large craft are about to leave the lock in your direction, and let the lockmaster know that you wish to lock through by:

  • Using VHF radio channel 16 to identify yourself and your intentions.
  • Using a marine whistle to signal one long blast for four to six seconds.
  • Pulling the small-craft signal cord located near the end of the upper and lower lock wall.
  • Once notified, the lockmaster will tell you how to proceed via radio or loudspeaker. Be sure to pay attention and obey the traffic signals:
    • A red flashing light means the lock is not available. Stand clear and do not enter.
    • An amber flashing light indicates the lock is being made ready. You may approach the lock guide wall, but do not attempt to enter the lock chamber.
    • A green flashing light means the lock is ready and you may enter the lock chamber.

In addition to traffic signals, the lockmaster will signal with horn blasts. One long blast means enter the lock; one short blast means exit the lock.

L&D 7

Enter and exit the lock at a no-wake speed. Follow the instructions for tying off or tossing lines to the lock tender. Do not tie your boat to the ladder or any other fixed point as the water level will change during the lockage. In a crowded lock chamber, you may be asked to tie off to another boat.

For safety reasons, the lockmaster has full authority over the movement and placement of vessels in the lock and its approaches. Failure to follow the lockmaster’s orders will not only delay the lockage, it can be dangerous.

Commercial traffic has the right of way

Lock near Rock Island, Ill.

Shut down your engines during the lockage, and have your passengers remain seated with everyone wearing a personal flotation device. Wait for the lockmaster’s signal before untying mooring lines to leave the lock.

As is with anything, there is a learning curve. Give yourself a week or two out on the river and you’ll be locking through with aplomb in no time!

For more information on the lock and dam locations and navigation notes, a full reference can be found in our printed guide here: