On April 28, 1944, Exercise "Tiger" ended with 750 US soldiers dead in a D-Day rehearsal after their convoy ships were attacked by German torpedo boats off Slapton Sands, Devon. Because of its top secret nature, many were unaware of the disaster. A short excerpt from the article:
"In the early morning hours of April 28, 1944, an Allied fleet slinked toward the coast of southern England. Along with a lone British corvette, the flotilla included eight American tank landing ships, or LSTs, each one of them filled to the brim with soldiers from the U.S. Army’s VII Corps. In just five weeks, these same troops were scheduled to land in France as part of Operation Overlord, the Allies’ secret plan to invade Nazi-held Western Europe. Overlord was integral to the Allied strategy for victory in World War II, and to ensure it went smoothly, military brass had organized a sweeping dress rehearsal codenamed “Exercise Tiger.” Before they stormed Utah Beach on D-Day, the men of VII Corps would get in a practice run at Slapton Sands, a picturesque British seafront that bore a striking resemblance to the coast of Normandy.
Exercise Tiger had begun six days earlier, when some 23,000 G.I.s assembled at staging areas in England. After putting to sea just as they would on D-Day, the men circled back for a series of simulated landings on the Devon seacoast, which was dressed up to resemble a warzone. The secluded beach at Slapton Sands had been converted into a maze of mines, barbed wire and concrete obstacles, and the nearby civilian population had been evacuated from their villages. To give the soldiers a taste of the chaos of battle, the British Royal Navy planned to shell the beach with live fire until just moments before the American troops made their mock landing."