SOO Locks

The Soo Locks are located at Sault Sainte Marie on the St. Mary's River, connecting Lake Superior and lake Huron. These parallel locks carry both commercial and recreational traffic through the 4 US locks and recreational traffic only through the Canadian lock. Most recreational sailors use the Canadian locks to avoid the huge commercial freighters.

The combined locks are the busiest locking system in the world with well over 10,000 vessels being locked through annually. Transit time is usually between 30 and 60 minutes.

US Locks

The US lock system uses the McArthur Lock for recreational vessels. The McArthur lock is the first lock from the shoreline. Contact the lockmaster on VHF Ch 14 to identify your vessel (description, registration number) and direction of travel. The lockmaster's call sign in WUD31.

Movements are controlled by RED or GREEN lights indicating whether to hold position or proceed into/our of the lock. A Fl YELLOW light indicates the lock is being readied.

Lines are provided by attendants but you may wish to use your own. If so, make sure you have at least 80 ft/25 m of line. Deploy fenders on your starboard side going downbound (Superior to Huron) and on your port side going upbound (Huron to Superior). Because of turbulence in the lock, post crew fore and aft with boat hooks to help stabilize your boat.

Canadian Locks

The Canadian Lock is the preferred system to use for recreational vessels. Here, you will not have to contend with commercial traffic. The locking method is straight forward. Approach to the Limit of Approach (L/A) sign. This is a large RED triangle with the WHITE letters L A. Contact the lockmaster on VHF Ch 14 using the call sign VDX23 Canadian Canal. State your vessel description and direction of travel.

The light signals are as follows:

  • RED: hold position
  • Fl RED: lock being readied
  • GREEN: proceed


Deploy fenders on your starboard side for upbound transit and on your port side for downbound transit. Use the fixed cables in the lock to hold your vessel in position and steady. DO NOT TIE OFF TO THESE CABLES. Simply pass a loose loop around them so your vessel can slide up or down along them. (Do otherwise and, like the WINDOC, you too may appear on YouTube!) If you have to use the south wall, have your own cable lines (80 ft/24 m) ready to use.

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