The Charbonnier site is in the middle of Baie St-François, opposite Valleyfield, a very busy area for recreational boating. It is marked with a buoy and is at a depth of 25 feet.
The bow and coal bunker attract a lot of fish. This site can be dived under ice since it offers a weak current and easy access in winter.
More details available at Scubarama’s Lac St-Francois, Charbonnier page:
in French,
English (Google Translate).