Sonar Survey Reveals the Lost WWII Ships of Dunkirk

A team of French and English researchers have surveyed the sites of 30 shipwrecks from Operation Dynamo, the sealift that saved Allied troops from advancing German forces at Dunkirk in 1940. 

Operation Dynamo, also known as "the Miracle of Dunkirk," involved the evacuation of hundreds of thousands of Allied soldiers who had been surrounded during the rapid German invasion of France. The port infrastructure at Dunkirk was quickly destroyed by German heavy bombers, so embarkation shifted to the beach and to an ad-hoc pier on the harbor's breakwater. To transfer the trapped and vulnerable troops, a swarm of 1,000 vessels - warships, passenger ships, fishing boats, workboats and yachts - made the crossing from England from May 26 to June 4, 1940. 

The effort brought 340,000 British and French troops across the Channel to England - but not without a cost. These ships were exposed to naval mines and the dive bombers of the German Luftwaffe, and more than 240 were sunk, including about 170 small craft. The vessels in this ad-hoc fleet were celebrated by the British government and remembered as "The Little Ships of Dunkirk."

The Royal Navy destroyer HMS Vivacious alongside a sunken trawler at Dunkirk, 1940 (Imperial War Museum)

Historic England and French research institute Drassm have worked together to plan a survey of the lost vessels of Dunkirk, and the mission began in late September. Archaeologists Cécile Sauvage and Claire Destanque of Drassm conducted the survey aboard the research vessel André Malraux, assisted by two geophysicists. Using a multibeam sonar, the team made a detailed three-dimensional profile of the seabed off Dunkirk. They found 27 wrecks from Operation Dynamo, including a dozen that were not previously located with precision. 

Three more previously-undocumented wreck sites were also discovered, bringing the total to 30. The survey also revealed that some of the known wrecks - like the lost British destroyer HMS Keith - are gradually deteriorating. 

The multibeam survey is the start of a longer campaign to investigate the wreck sites and document them in their current state. Next year, in partnership with local divers, Drassm's researchers will return to carry out a detailed dive survey. 

A three-dimensional sonar depiction of the passenger vessel Normannia, which was requisitioned for the Dunkirk evacuation (Drassm / Historic England)