Lock 20Ontario


Dive site characteristics

Types Structure dive Drift dive
Conditions Visibility very restricted or null
Providers Parking Swimming Picnic tables W.C. Bathroom
Planning Rescue in case of emergency Weather conditionsFerries scheduleRoad conditionsRoad maps

Diving notes

It is important to take good reference point with the compass before diving. The visibility is sometime poor. The return has to be done in the right direction! The essential thing to remember is if you go against the current, the exit is on your right while with the current, the exit is on your left.

Entry points


Note: directions are accurate as possible. It is recommended to go with someone who knows the site.

  Depth   Site  Characteristics
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120mLock 21 Descent along the line of the buoy which leads to the 30′ deep structure. The inner lock may reach 60′ deep. Watch your air constantly (rule of thirds) and the current which may get strong sometimes. The usual traject is to follow the transversal axis North-South and the promenade (West-East). This is not a dive for beginner. Visibility may change during season as well as current which mostly vary with rain conditions and the opening of the Cornwall power dam.
2?DamSheik Island dam. Informations to come.
330′Cimetière de barges
Barges cimetery 
Remains of 3 barges can be found, largely deteriorated at about 30′ deep. Visibility is very low. On the South side, there is a rope leading to the next site (Dread) at about 150′ at the South.
450′Dread Another damaged barge still having some equipment such as anchors and cabestan. The rope on the North side brings you back to the cemetery, the one on the South to the other site (Belly Dumper) at 400′ on the South-East.
580′Belly Dumper The barge is directly under the buoy. It is a wooden barge sitting on its side. It was used during the St.Lawrence Seaway construction. You will go around very quickly.
630′Quai du parc
Park wharf 
It is the old wharf. A dive flag is recommended as everywhere in Ontario.
730-65′Swing bridgeJust West of Milles Roches Power House. Only old stone piliars remains.
835-75′Power House Boat access. Follow the buoy line down to the 1st level at 30′. You may go down to the 2nd level at 55′ and then to the 3rd level at 75′.
960′Control damAccess by boat, on the East side of the Power House.
1075′Lock 20 Dive for expert only. Located à about 1km West of Cornwall dam (Moose Saunders Power Dam).

Driving directions

From highway 401, take exit 778 toward Long Sault. Take the South direction on Moulinette Road up to road 2 (also known as King’s Highway).


To get to Lock 21

Continue heading South direction on Moulinette Road crossing road 2 toward to Long Sault Parkway. You will have to stop and pay your entry fee (3.25 CAN$ per person; summer 2003). It is free the rest of the year. Follow the route up to the McDonnell Island (2nd island).

After driven half way of the island take then the 2nd gravel road and follow toward West direction. There is a brown pavilion (yellow square on the diagram) where informations are available about the dive site and an historic tour relating the story of the Lost Villages after the construction of the St.Lawrence Seaway. The Lock is located on the South side of the island on the St.Lawrence lake (not the St.Lawrence River which is located on the other side of the islands on the American side of the border). You may park your vehicule near the shore unless indicated. Please take note that CAN-US border is located at about 100 feet from the shore (30m).


To get to other sites

From highway 401, take exit 778 toward Long Sault. Take the South direction on Moulinette Road. Turn left on road 2 or Vincent Massey Drive. Follow the route 4.8km, heading East (passed the Lost Villages Museum) up to Guindon Park (take the West entry on the map).

Diver’s services

Providers Address Phone Services
Long Sault Parkway  County Road 2,
Cornwall
800 437-2233
613 543-4328
site access to lock 21
Ron’s Scuba Shop 13, 11th Street West,
Cornwall
613 933-1362 air, rentals,

© Copyright 1999-2016, Michel Robitaille. All rights reserved.