Early on 27th April 1944, several landing craft approached a pebbled beach on the English Channel, carrying U.S. troops armed to the teeth. As the ramps dropped, the men sprang into action, quickly wading ashore, even as machine gun bullets whizzed above their heads. Then came the explosions as shells rained down. Although initially, the troops continued their advance, they were soon forced to dive for cover when it became clear that people were being killed. This was not supposed to happen. After all, this was not enemy territory, and the shells came from their own side.
The beach in question was Slapton Sands, on the South Devon coast of England, and the action was part of Exercise Tiger - one of the last dress rehearsals for the Allied landings in Normandy set to take place less than six weeks later. Carried out under conditions of utmost secrecy, Exercise Tiger was one of the largest and most ambitious ever conducted. It was also an unmitigated disaster. The friendly fire episode was not even the worst incident but just the start of a disastrous affair that would result in the deaths of several hundred U.S. servicemen.
In January 1942, shortly after the United States had formally entered World War II on the Allied side, the first of what would eventually total more than 1.5 million American servicemen began arriving in the British Isles, anxious to join the fight against Hitler. Over the next two years, men and materiel flooded across the Atlantic in a bid to build up strength for an eventual invasion of mainland Europe. In 1943, planning began for Operation Overlord, set to take place in June 1944: After four long years under Nazi occupation, the stage was set for the liberation of France.
As the date of the invasion approached, realistic exercises involving large-scale amphibious landings and mock battles with live ammunition became necessary. Accordingly, in November 1943, British authorities established a large training area around Slapton Sands to be used by those U.S. forces tasked with landing on Utah Beach. The choice of location was due to the similar topography of the two beaches. To maintain secrecy, Compulsory Evacuation Orders were issued, giving residents six weeks to evacuate an area of some 30,000 acres. Around 3,000 men, women, and children, some of whom had never left their homes before, were forced to move away, taking with them their belongings, livestock, pets, and farm equipment. In their place, around 15,000 U.S. troops moved in.
Training in the area began the following month so that by April 1944, no less than ten exercises had been held. The 11th and 12th exercises, codenamed 'Tiger' and 'Fabius 1', would be full dress rehearsals for the U.S. VII Corps landings on Utah Beach. Exercise Tiger, under the command of Rear Admiral Don P. Moon USN, was to take place between 22nd and 30th April and would cover all aspects of the invasion, including two waves of beach landings at Slapton Sands, an advance inland, and the landing of further supplies on the beach. To simulate the invasion as realistically as possible, the troops and their equipment would be embarked on the same ships that would later take them to France. They would also leave from the same ports. Meanwhile, the beach at Slapton Sands had been transformed, with minefields, barbed wire entanglements, and concrete obstacles.
The first phase of the exercise, held between 22nd and 25th April, focused on marshalling and embarkation drills. This involved mobilising large numbers of troops from their respective camps and loading them, with all their equipment and vehicles, onto landing craft at various embarkation points along the English Channel. Whilst this training was vital for the future success of the invasion, it had to be accomplished without alerting the enemy to what was coming. The second phase began on the evening of 26th April, when the first wave of assault troops set off on their journey towards Slapton Sands, via a circuitous route through Lyme Bay to simulate crossing the Channel. They were scheduled to arrive off the beach at first light the following morning. Unloading would continue throughout the day and the next when a follow-up convoy was expected.
In the meantime, the Supreme Allied Commander of the Allied Expeditionary Force, General Dwight D. Eisenhower, had become increasingly concerned by the youthful inexperience of most of the new U.S. conscripts arriving in England, most of whom had never seen action before. He believed that for the invasion to be successful, the men had to be hardened by exposure to real battle conditions, to prepare them for what lay ahead. As a result, the training would have to be as realistic as possible: The men would have to experience seasickness, wet clothing, and the use of live ammunition. Accordingly, the men landing at Slapton Sands on the morning of 27th April would not only have genuine bullets fired over their heads but would also be supported by real naval artillery.
H-hour was set for 7.30 am. Exactly an hour before, the British heavy cruiser HMS Hawkins was to subject the beach to a 30-minute naval bombardment using live shells. This would leave a full 30 minutes for beach wardens to inspect the area for unexploded ordnance and certify that it was safe for the troops to make landfall. Unfortunately, some LSTs (Landing Ships, Tank) in the convoy fell behind schedule, leading Admiral Moon to delay H-Hour by 60 minutes, to 8.30 am. While this message was received onboard HMS Hawkins, it did not reach the leading LSTs, which proceeded according to the exercise’s initial timetable. As a result, the troops began landing on the beach just as the now-rescheduled naval bombardment got underway.
As the leading troops from the U.S. 4th Infantry Division made their way onto the beach, shells rained down on them, inflicting casualties. Although the exact number was never disclosed, rumours circulated that hundreds of men had been killed, many supposedly being buried in unmarked graves in the area to hide the extent of the tragedy, even though no supporting evidence has ever come to light. In the meantime, the exercise continued once the fire had been called off. The assault troops were to move inland to link up with airborne forces already transported to the area overnight, though in lorries rather than aircraft. The beach at Slapton Sands was officially secured by 3.30 pm, although, as it turned out, the worst disaster to befall Exercise Tiger was yet to unfold.
A follow-up convoy was expected to arrive at Slapton Sands at 7.30 am on the following morning, 28th April. Convoy T-4, commanded by Commander Bernard J. Skahill USN, consisted of eight LSTs and their escort. On the morning of 27th April, USS LST-58, USS LST-496, USS LST-511, USS LST-515, and USS LST-531 departed from Plymouth, whilst USS LST-289, USS LST-499, and USS LST-507 left from Brixham. They were transporting a follow-up force of supporting units, including combat engineers from the 1st Engineer Special Brigade, quartermaster, signal, and medical troops in full combat gear, as well as tanks, trucks, jeeps, and other vehicles loaded with fuel and ammunition.
Due to the Royal Navy’s many commitments in the English Channel and the Atlantic, Convoy T-4 was originally afforded only two escorts. This was reduced to one when the destroyer HMS Scimitar sustained damage in a collision with an LST and was detained in Plymouth for repairs. No replacement was immediately available, and thus the convoy now had to make do with just one escort, the Flower-class corvette HMS Azalea, commanded by Lieutenant Commander George C. Geddes, and armed with just one 4-inch gun and two pairs of machine guns. Azalea linked up with the LSTs at 11 am and the convoy proceeded in single column at a speed of six knots.
Apart from the close escort for Convoy T-4, the Royal Navy also provided further protection for Exercise Tiger. Four O-class destroyers, three motor torpedo boats (MTBs) and two motor gunboats (MGBs) patrolled the entrance to Lyme Bay. Another three MTBs were stationed off Cherbourg to keep a sharp lookout for any German Schnellboote based there. Known to the Allies as E-boats, these heavily armed, fast craft, capable of operating at a top speed of around 43 knots, were known to regularly patrol the English Channel. Apart from the threat they posed to the convoy, it was also imperative that they be kept away from the area to make sure the Germans were not tipped off about the upcoming invasion.
On the night of 27th/28th April 1944, the seas off the south coast of Britain were exceptionally busy. Apart from the numerous vessels involved in Exercise Tiger, other groups of ships were also in the vicinity. These included routine coastal convoys, which, as a result of the training exercises being carried out around the coast, were being forced to sail further out into the English Channel, bringing them closer to the coast of France. In the meantime, the German Naval Intelligence Service was known to analyse radio traffic and use direction finding to direct E-boats towards potential targets. Indeed, at 10 pm on 27th April, nine German E-boats left Cherbourg following reports of a convoy to the west of the Isle of Portland. This was most likely Convoy WP.513, consisting of 20 ships, headed to Portsmouth from Milford Haven, Wales.
The E-boats in question were S 100, S 136, S 138, S 140, S 142, and S 143 from 5. Schnellbootflottille, under the command of Kapitänleutnant Bernd Klug, and S 130, S 145, and S 150 from 9. Schnellbootflottille, led by Kapitänleutnant Götz Freiherr von Mirbach. Having avoided the British MTBs watching the port, they proceeded towards Lyme Bay in four groups: The three boats from 9. Schnellbootflottille remained together, while the six from 5. Schnellbootflottille broke down into pairs to sweep ahead of them. At least three of these groups were detected by radar, with a message being sent out just after midnight that contacts had been obtained west-southwest of Portland Bill, seemingly heading into Lyme Bay.
Shortly afterwards, S 136 and S 138 spotted two destroyers that were part of the protective screen for Exercise Tiger. They engaged with torpedoes but did not hit anything, although a loud explosion was witnessed by both the German and British vessels. This was most likely caused by a premature detonation and led to a report from HMS Onslow about E-boat activity in the area. Incredibly, although the Royal Navy was thus alerted to the presence of the enemy vessels, the Americans were not forewarned due to a typographical error, which meant they were operating on a different radio frequency. HMS Azalea received the messages, but unknown to her captain, the LSTs did not.
As a result of their unsuccessful engagement with the British destroyers, S 136 and S 138 had exhausted all their torpedoes and thus decided to withdraw from the action. The remaining seven E-boats had penetrated the destroyer screen and become lost in the radar clutter of the numerous vessels operating in the area. Just after 1 am, S 140 and S 142 came across several small landing craft. These probably belonged to Convoy TM.5, sailing from Teignmouth and Exmouth towards Slapton Sands. Once again, torpedo attacks proved ineffective, much to the dismay of the E-boat crews, who eventually concluded that they must have been firing below their targets due to the latter’s shallow draft.
This latest attack took place in the vicinity of Convoy T-4, still on its planned route towards Slapton Sands. Some of the LSTs in the convoy had been alerted by the sound of gunfire and flares and come to General Quarters in response. However, since an attack on themselves did not immediately materialise, they were eventually stood down, meaning that another vital opportunity to steer the convoy away from danger was missed. As it turned out, S 140 and S 142 had indeed detected the deeper draft LSTs of Convoy T-4 and reported their position to the remaining E-boats, which sped to the area, eager to join the attack.
The eight heavily laden, slow-moving LSTs, perfectly lined up one after the other, were caught completely off guard by the E-boats, which first targeted the unprotected rear of the convoy. Just after 2 am, LST-507 was struck by a torpedo fired by S 130. All lights onboard immediately went out following an explosion in the auxiliary engine room. Fire quickly spread to the parking deck, where vehicles were fully loaded with fuel and ammunition. Soon, the whole LST was ablaze, forcing survivors to abandon ship. As men jumped into the burning sea, radio operators aboard the other LSTs sent urgent queries but received no reply. Thus, the convoy, by now stretched out over several miles, continued along its course, oblivious to LST-507‘s fate. The E-boats, meanwhile, prepared for a second pass.
At 2.16 am, S 143 fired two torpedoes towards LST-531, located in the middle of the convoy. Both struck home in quick succession just over a minute later. The order was given to abandon ship, but there was little time to launch the lifeboats as, within six minutes of being hit, LST-531 had disappeared beneath the waves, taking hundreds of men down with her, trapped below decks. Many of those who leapt into the sea drowned under the weight of their kit, while others quickly succumbed to hypothermia in the frigid waters.
By now, the remaining six LSTs were zigzagging and firing wildly into the darkness. At 2.28 am, gunners on LST-289, which had been just in front of the recently sunk LST-507, opened fire on what they believed to be an E-boat. Moments later, they were hit by a torpedo launched by S 145. The resulting explosion turned the stern of the LST into a mangled hulk, although, luckily, she did not sink and would eventually make it to shore. The E-boats scored no further hits, but LST-511 was caught in the crossfire and suffered damage. Taking advantage of the confusion, and satisfied with their night’s work, the E-boats made their escape, using smoke to mask their retreat. Although aircraft were sent to hunt them down, all made it safely back to Cherbourg.
In the meantime, the surviving vessels of Convoy T-4 were ordered to make for the nearest port. Hundreds of survivors were still in the water, hoping to be rescued. The destroyer HMS Saladin soon arrived on the scene, as did LST-515. Her captain, Lt. John H. Doyle USN, could not bring himself to leave men to drown and decided to disobey orders and return to the area. His crew rescued approximately 134 men who would have surely perished. Yet hundreds of bodies could be seen bobbing on the surface. Many had drowned due to not having been shown how to wear their lifebelts correctly. Casualties were taken to Dartmouth and Portland Harbour, with around 50 U.S. Army ambulances turning up to ferry the wounded to nearby facilities.
The sinking of LST-507 resulted in the loss of 202 U.S. Army and Navy personnel. Casualties on LST-531 were even worse. Of the 496 soldiers and sailors aboard, 424 were lost. The damaged LST-289 returned to port having lost 13 U.S. Navy personnel, while the friendly fire that had hit LST-511 resulted in injuries to 18 men. Total casualty figures were later given as 441 Army and 198 Navy personnel dead and missing. This total of 639 later went up to 749 when 110 other casualties resulting from training accidents were seemingly folded into the Exercise Tiger casualty numbers. The U.S. Department of Defense later stated that record-keeping aboard some of the ships may have been inadequate, leading to claims that the number of casualties may have been even higher. In any case, the official figures mean that Exercise Tiger was the costliest training incident involving U.S. forces during World War II.
Eisenhower was furious when news of the attack reached him. Apart from the deaths of hundreds of troops, the loss of two LSTs and serious damage to a third was a huge blow. Just over 100 LSTs were available for D-Day, and no other vessel could perform the same job of repeatedly delivering substantial quantities of heavy equipment directly onto the beaches. These vessels could not be easily replaced. Additionally, there was also the security factor. The fact that the Allies were training with landing craft would likely signal to the Germans that an invasion was imminent. The worst part, however, was that among the missing were ten officers from the 1st Engineer Special Brigade with intimate knowledge of the invasion plans. There were real fears that should they be captured alive, the whole plan would be compromised. Luckily, all ten bodies were identified from among the 248 recovered from the sea over the next four days. The D-Day secret was secure.
This need for secrecy led to the whole debacle being kept under wraps over the next weeks. Survivors were told not to speak about what had happened and threatened with court martial. The same applied to doctors and nurses who had treated the survivors, and anyone else in the know. This would later lead to accusations of an official cover-up. In truth, this initial security clampdown was ended in August 1944, when Supreme Headquarters, Allied Expeditionary Force released statistics on the casualties associated with the Normandy invasion. This included information about Exercise Tiger. In light of the larger events occurring at the time, this press release went largely unnoticed and received little public attention. The casualty list from Exercise Tiger was buried among many other longer casualty lists. The tragedy was never covered up but just conveniently forgotten.
A subsequent investigation revealed that two main factors had contributed to the tragedy: The lack of escort vessels and the error in radio frequencies. Whether an absence of either or both of these factors would have helped avoid the tragedy that unfolded will never be known for sure. The lack of proper training on the use of life vests and the effects of cold water, which led to many succumbing to hypothermia before they could be rescued, also contributed to the disaster. At least some positives resulted from this incident, as the Allies learned vital lessons before launching the invasion. Radio frequencies were standardised. Better lifejacket training was provided to the troops, while plans were made for small craft to pick up floating survivors. These lessons were applied during Exercise Fabius I, which took place without a hitch in early May. Crucially, the Allied commanders realised that the E-boats in Cherbourg provided a major threat to the invasion force and would need to be dealt with.
The 248 bodies that had been retrieved from the sea were initially buried at the Brookwood American Cemetery in Surrey. After the war, their families were given the choice of having their loved ones shipped back to the U.S. for reburial, or re-interred at the Cambridge American Cemetery, where the names of those whose bodies were never recovered were also listed on the Wall of the Missing. It was not until the 1980s that a memorial was erected at Slapton Sands, largely due to the efforts of local resident and amateur historian Kenneth Small.
There is no doubt that the tragedy of Exercise Tiger contributed to a reduction of casualties on 6th June 1944. Incredibly, more Americans died during this disastrous manoeuvre than on Utah Beach on D-Day itself. Many survivors of Exercise Tiger would later claim that landing on enemy territory was a walk in the park compared to the experience of coming under attack by the E-boats on that fateful night. Although hundreds of men being killed on a training exercise seems like a terrible waste of lives, it must be remembered that the dead of Convoy T-4 were combat fatalities just like those who died during the actual invasion. They died in action with the enemy and their sacrifices were no less heroic.
References
Ryan, C. (2024, April 16). Exercise Tiger – The Battle of Lyme Bay. Navalhistoria.com. Retrieved January 26, 2025, from https://navalhistoria.com/exercise-tiger/#Phase-1:-Advance-to-Contact-27-April
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