When you are in Québec City, you will find the members at the Yacht Club de Québec are impressively hospitable (whether you speak English or French). The Club is a mile or so further up the River from where the first picture was taken. If you ask, they will tell you about their hosting of Transatlantic races. They are also are a wealth of knowledge if you are cruising further down the St Lawrence. Their initiative established the harbour at Cap à l'Aigle for the convenience of cruisers.
The picture shows the YCQ yacht basin at low tide. High tide is 15-19 higher!