A PROJECT mapping the history of seven top secret tanks sunk off the Purbeck coast during preparations for D-Day is under way.

Divers laid a memorial wreath on one of the Second World War ‘Valentine’ tanks, as the underwater phase of the Isle of Purbeck Sub-Aqua Club (IPSAC) initiative commenced in Poole Bay.

Speaking afterwards, Nick Reed, of IPSAC, said: “Conditions this morning were totally different than that fateful day in 1944. The tanks were launched in rough weather with a big swell. Seven of the tanks were swamped and sank, sadly with the loss of six soldiers.”

Six weeks before D-Day, Prime Minister Winston Churchill, King George VI and General Dwight D. Eisenhower - Supreme Commander of the Allied Forces - met at Fort Henry, near Studland, to watch a rehearsal of the assault to come.

As Exercise Smash unfolded, a number of the Valentines - which had been equipped with propellers and canvas skirts to make them amphibious - were deployed. However, rough seas claimed seven of them.

The Valentine 75 project has been launched to map the history of these tanks, their crews and the men who perished during the D-Day rehearsal of April 4, 1944.

Of the seven that sank, two remain submerged in 15 metres of water off Studland.

The other wrecks were blown up by the Royal Navy after being deemed a threat to shipping.

Mr Reed said: “The project will spend the next two years recording and surveying the seven Valentine tanks wrecks in Poole Bay.

“The tanks were, at the time, a top secret design and were taking part in Exercise Smash, a major training exercise in preparation for D-Day.”

Charles Robert Gould, Victor Hartley, Albert Victor Kirby, Arthur Jackson Park, Earnest Granville Petty and Victor Noel Townson, of the 4th/7th Royal Dragoon Guards, drowned when rough weather swamped their Valentines during Exercise Smash.

In 2019 the club will mark the 75th anniversary of the Studland Bay operation.