You could call the Tadaussac Marina and ask for Shaun. He speaks excellent
english (assuming that matters) and is very helpful. He might be able to give you some leads. It's important to time the tides around there carefully as there are very strong currents. I wouldn't do it in a sailboat without a good aux
engine. Be sure to plan on spending a day or more at Eternity Bay. It's a beautify spot with 5 or so moorings that are first come, first serve. Also keep in mind that there are very few places where you can
anchor so you will need to plan your legs carefully. Most places drop straight down to 100's of feet
depth. But it's an awesome place and the Belugas are a real treat.
Here's a blog on the area from last summer
Adventures of Tanglewood: The Saguenay River