Surcouf: French Submersible Cruiser

This 110 meters, 3300 tons behemoth was built to take advantage of a loophole in the Washington naval treaty. It was first deployed in 1934 and was armed with 6x 550 mm and 4x 400 mm torpedo tubes and a twin 203mm gun turret fed by a 60 rounds magazine.

The guns could strike at a target at a distance of 11km only 3 minutes after having surfaced. This “Ocean-Going Cruiser Submarine” also embarked an observation seaplane and a motorboat in watertight cargo holds.

Surcouf’s Service During WWII

When the Germans invaded France in 1940, Surcouf was in Cherbourg. Her crew sailed her to Plymouth to evade capture. The French vessel was later involved in convoy escort duty across the Atlantic.

Surcouf was a one-off complex design and her propulsion system, armament, sensors and equipment often broke down. A lot of her experienced crew had departed once they arrived in England in 1940 and she was subsequently manned by a hodgepodge of French Navy personnel.

Challenges and Disappearance

The British admiralty had a very low opinion of the ship, its crew as well as suspicions regarding the crew’s morale and discipline. Furthermore, the Brits and the Americans were also suspicious as far as the French crew’s interests in the allied cause and even suspected some French sailors’ loyalties.

She mysteriously disappeared sometime in February 1942 in the Caribbean, fueling countless conspiracy theories.

-RBM