Designed by the naval architect Emile Bertin, the Gueydon-class ships were intended to fill the commerce-raiding strategy of the Jeune École.

Steam for Dupetit-Thouars's engines was provided by 28 Belleville boilers and they were rated at a total of 22,000 metric horsepower (16,000 kW) that gave them a speed of 22 knots (41 km/h; 25 mph).

The explosions killed three men, and neither the submarine nor her periscope were spotted, although a Lieutenant detected the first torpedo shortly before it hit.

They moved the ship off the route of the convoy, radioed a distress call, and stopped the engines to allow the crew to evacuate.

Fifty minutes after the torpedo hit, Dupetit-Thouars rolled over and sank, killing ten sailors still aboard trying to launch the last raft.

[4] The survivors spent 16 hours in boats and rafts before being rescued the next day, in late afternoon, by six US destroyers Tucker, Drayton, Winslow, Porter, Warrington and Fanning.