The Mysterious Disappearance of the Surcouf, the Largest Cruiser Submarine of World War II

Surcouf was a large French gun-armed cruiser submarine of the mid 20th century. She carried two 8” guns as well as anti-aircraft guns and (for most of her career) a floatplane. Surcouf served in the French Navy and, later, the Free French Naval Forces during the Second World War.

Surcouf disappeared during the night of February 18-19, 1942 in the Caribbean Sea. She was named after the French privateer and shipowner Robert Surcouf. She was the largest submarine built until surpassed by the first Japanese I-400 class aircraft carrier submarine in 1944.

In January 1942, the Free French leadership decided to send Surcouf to the Pacific theatre, after she had been re-supplied at the Royal Naval Dockyard in Bermuda. However, her movement south triggered rumors that Surcouf was going to liberate Martinique from the Vichy regime. In fact, Surcouf was bound for Sydney, Australia, via Tahiti. She departed Halifax on February 2 for Bermuda, which she left on February 12, bound for the Panama Canal.

Surcouf vanished on the night of February 18-19, 1942, about 130 km (70 nmi) north of Cristóbal, Panama, while en route for Tahiti, via the Panama Canal. An American report concluded the disappearance was due to an accidental collision with the American freighter Thompson Lykes. Steaming alone from Guantanamo Bay on what was a very dark night, the freighter reported hitting and running down a partially submerged object which scraped along her side and keel. Her lookouts heard people in the water but, thinking she had hit a U-boat, the freighter did not stop although cries for help were heard in English. A signal was sent to Panama describing the incident.

The loss resulted in 130 deaths (including 4 Royal Navy personnel), under the command of Frigate Captain Georges Louis Nicolas Blaison.  The loss of Surcouf was announced by the Free French Headquarters in London on April 18, 1942, and was reported in The New York Times the next day. It was not reported Surcouf was sunk as the result of a collision with the Thompson Lykes until January 1945.

The investigation of the French commission concluded the disappearance was the consequence of misunderstanding. A Consolidated PBY, patrolling the same waters on the night of February 18-19, could have attacked Surcouf believing her to be German or Japanese. This theory could have been backed by several elements:

• The witness testimonies of cargo ship SS Thompson Lykes, which accidentally collided with a submarine, described a submarine smaller than Surcouf
• The damage to the Thompson Lykes was too light for a collision with Surcouf
• The position of Surcouf did not correspond to any position of German submarines at that moment
• The Germans did not register any submarine loss in that sector during the war.

Inquiries into the incident were haphazard and late, while a later French inquiry supported the idea that the sinking had been due to “friendly fire”; this conclusion was supported by Rear Admiral Auphan in his book The French Navy in World War II. Charles de Gaulle stated in his memoirs that Surcouf “had sunk with all hands.”