This water highway is at some spots as narrow as a large river and, at others, as wide as a small sea. It has played a vital role over the last three centuries as an important artery for trade, communication, transportation and settlement. And since 1959, the year the St. Lawrence Seaway was inaugurated, it has been a gateway to the heart of the continent.

The first European explorers who sailed the St. Lawrence discovered it was not easy to master: it was long, but never calm. After crossing the Gulf, mariners would face many difficulties navigating up the river to Québec City, including narrow, sinuous channels, shallow waters, shoal deposits and strong tides. Currents are sometimes unpredictable, there can be very dense fog, and, of course, the river is impossible to navigate in winter. No one ventured on its waters from the end of November to the beginning of May.

Qualified maritime pilots are a must on the capricious and indomitable St. Lawrence, which has the reputation of being one of the most difficult rivers to navigate in the world. The risk of collisions, groundings and shipwrecks is high, which led to tightened navigation safety regulations, particularly in response to the accidents involving large ships that occurred in the 1960s.

It is estimated that there are several thousand wrecks below the surface of the river.

As a doctoral student in geographic sciences at Laval University and president of the Technical Wreck Divers of Québec (PETQ), I propose introducing you to the three most important shipwrecks in terms of size that took place in the river. Our diving activities push the very limits of exploration. Notably, we use diving techniques adapted to the particularly restrictive underwater context of the St. Lawrence, with its strong currents, often reduced visibility and cold, black water, among other hazards.