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History
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Exercise Tiger: The Secret D-Day Rehearsal That Became a Massacre
Weeks before D-Day, a catastrophic rehearsal known as Exercise Tiger resulted in the deaths of 749 American servicemen off the English coast. A combination of a surprise German attack, friendly fire, and equipment failures was concealed for decades to protect the invasion, hiding a devastating loss.
In the spring of 1944, the air in southern England was thick with anticipation and secrecy. The Allied forces were in the final stages of preparing for Operation Overlord, the monumental invasion of Normandy that would turn the tide of World War II. To ensure its success, a series of full-scale rehearsals were planned. The largest and most critical of these was codenamed Exercise Tiger, a dress rehearsal for the landings on Utah Beach. But this crucial practice run, intended to save lives on D-Day, would descend into a tragedy so profound that it was immediately shrouded in secrecy, its story all but erased from the history books for nearly forty years.
A Stage Set for Disaster
The exercise took place in late April 1944 at Slapton Sands in Devon, a stretch of coastline chosen for its striking resemblance to Utah Beach. Thousands of American soldiers from the 4th Infantry Division, along with a flotilla of Landing Ship, Tanks (LSTs), gathered to simulate every phase of the invasion. To make the training as realistic as possible, General Dwight D. Eisenhower ordered the use of live naval and artillery ammunition, timed to be fired over the heads of the incoming troops to acclimate them to the chaos of a real battlefield.
This decision, while logical in theory, was the first link in a chain of catastrophic events. On April 27th, due to a timing miscommunication, live shells from the British cruiser HMS Hawkins rained down on the beach as American troops were landing. The friendly fire incident is estimated to have killed over 300 servicemen before the main tragedy had even begun.
The Ambush in Lyme Bay
The true heart of the disaster struck in the pre-dawn hours of April 28th. A convoy of eight LSTs, designated Convoy T-4, was making its way through Lyme Bay. The ships were packed with soldiers, tanks, and equipment, moving slowly toward the Devon coast. They were supposed to be protected by two British Royal Navy vessels, but a series of fatal errors left them vulnerable.
One of the escorts, HMS Scimitar, had been damaged in a collision and was forced to return to port for repairs, leaving only the corvette HMS Azalea to guard the long line of lumbering transport ships. Critically, the American LSTs and the British escort were operating on different radio frequencies. When British naval command spotted a group of German E-boats (fast attack craft known as 'Schnellboote') in the area and transmitted a warning, the American ships never received it.
Just after 2 AM, nine German E-boats from the 9th Flotilla swarmed the convoy. They fired torpedoes with devastating effect. LST-507 was hit and erupted in flames. LST-531 was struck and sank in under six minutes, taking hundreds of men down with her. A third ship, LST-289, was set ablaze but managed to limp back to shore.
"We were all told to keep our mouths shut. We were told it never happened. We were survivors, but we weren't supposed to talk about it. It was a big secret. If we talked, we were told we'd be court-martialed."
The chaos in the water was horrific. Many soldiers, unfamiliar with their life preservers, had worn them incorrectly around their waists instead of under their arms. When they jumped into the frigid sea, the weight of their combat packs flipped them upside down, forcing their heads underwater and causing them to drown. Those who survived the initial blasts faced death from hypothermia in the cold English Channel.
A Wall of Silence
In the aftermath, the Allied high command moved swiftly to conceal the disaster. With the Normandy invasion just weeks away, news of such a staggering loss of life could have crippled morale and, more importantly, tipped off the Germans about the location of the impending landings. Survivors were sworn to secrecy under threat of court-martial. Medical personnel were ordered to alter the death certificates of the victims. The 749 American soldiers and sailors who perished during Exercise Tiger were effectively erased from the narrative of the war.
For decades, the story remained a closely guarded secret. It wasn't until a local man in Devon, Ken Small, began finding military artifacts on Slapton Sands in the early 1970s that the truth started to surface. Driven by curiosity, he began a years-long investigation that uncovered the forgotten tragedy. In 1984, after a tireless campaign, he recovered a submerged Sherman tank from the bay, which now stands at Torcross as a permanent memorial to the men who died in the rehearsal for D-Day.
The lessons learned from Exercise Tiger—particularly regarding radio standardization and proper life vest training—undoubtedly saved lives during the actual Normandy landings. But that knowledge came at a terrible cost, a price paid by hundreds of men whose sacrifice was hidden by the fog of war for far too long.