Autonomous submarines have been sent to examine two US tank landing ships sunk off the coast of Devon in the run-up to the D-Day operation.
In the first attempt to access the two vessels damaged by torpedoes on 28 April 1944 during the Exercise Tiger rehearsal, the underwater drones collected data from the site, which were used to create the first high-definition sonar images of this Second World War tragedy.
The Royal Navy's Maritime Autonomous System Trials Team (MASTT) was in charge of the venture using the REMUS 100 unmanned submarines provided by American manufacturer Hydroid.
The REMUS 100, equipped with multiple sonar instruments enabling acquisition of high-resolution imagery of objects on the sea floor, is designed to perform intricate oceanographic surveys over large areas.
Side scan images acquired by the Hydroid and its wide swath interferometric bathymetric multi-beam sonar show that both LSTs are resting on the seabed about 50 meters below the surface and reach between six to eight meters above the seafloor. The submarine also discovered an object of interest close to the shore which may hold significance in relation to Exercise Tiger. An effort to identify this object is currently underway by the Royal Navy.
The attempt to map the wrecks was conducted to commemorate the 70th anniversary of Exercise Tiger – a tragic but largely unknown military operation, carried out as a rehearsal for the invasion of Normandy's Utah Beach.
"We hope that the data collected on this mission will shed additional light on this tragic event and help bring some closure to the families who lost their loved ones during Exercise Tiger," said Richard 'Bungy' Williams, Regional Manager, Hydroid Europe. "We are proud to use our technology to honour the memories of the servicemen who lost their lives in this tragic operation."
Exercise Tiger took place off the southern English coast and resulted in the loss of nearly 1,000 American servicemen - more than the number of soldiers killed during the actual invasion. After intercepting radio communication related to the exercise, the Germans sent nine torpedo boats to investigate the situation. The boats attacked the landing ship tanks, killing almost 1,000 men.