At 18.33 hours on 15 Sep, 1942, U-517 fired four torpedoes at the convoy SQ-36 four miles from Cape des Rosiers in the Gulf of St. Lawrence and reported one ship sunk and another damaged. In fact, the Inger Elisabeth and Saturnus were hit and sunk by one torpedo each. The U-boat had followed the convoy since the afternoon of the day before and tried to chase it further but lost contact in fog.

The Saturnus was hit in the stern, which was completely destroyed and a gunner on watch at the stern gun was killed. The survivors launched both lifeboats before the ship sank after ten minutes and they made it to shore by themselves.