Exercise Tiger

Slapton Sands is a long shingle beach on Start Bay in south Devon. Immediately behind it lies Slapton Ley, a narrow lake and marsh separated from the sea by the beach ridge. That combination resembled the flooded ground behind Utah Beach closely enough for VII Corps to rehearse the assault there.

The exercise stretched well beyond the beach. Troops embarked from ports around Plymouth and the south Devon coast, then approached Slapton by sea. Follow-up LSTs had to move through Lyme Bay before turning toward the exercise area. That made the rehearsal a test of convoy control, escorting, navigation and communications as well as a landing drill.

The attack on Convoy T-4 happened east of the beach, in open water off the Devon coast. The two sunken LSTs still lie in Lyme Bay. Their wrecks are now protected sites and provide a fixed archaeological record of a disaster that unfolded in darkness, cold water and scattered burning fuel.

VII Corps wanted the exercise to reproduce the Utah assault as closely as possible. Raymond Barton therefore used the same regimental combat-team structure planned for Normandy, with engineers, tanks, artillery and support units folded into the landing sequence. The scale was deliberate. Problems discovered in Devon still had several weeks to be corrected.

On 27 April Rear Admiral Don Moon moved the assault hour from 07:30 to 08:30. The change did not reach every unit. Company G of the 8th Infantry came ashore on the original timetable while the rescheduled naval bombardment began. A recent US Army review concludes that the heavy naval guns did not hit the company, although explosions landed close enough to demonstrate how dangerous a last-minute timing change could become.

The convoy attack exposed a second coordination failure. HMS Azalea remained with Convoy T-4, while the intended second escort, HMS Scimitar, was unavailable after damage. Communications between British escorts and American LSTs were also poor. The German S-boats therefore found a slow convoy with limited protection and no common picture of the threat.

The LST was the essential machine of the follow-up force. Its flat bottom and bow ramp allowed tanks, trucks and DUKWs to move directly from ship to beach. Those same ships carried fuel, ammunition and hundreds of men. When torpedoes opened the vehicle decks, fire spread through exactly the cargo needed for an invasion.

The German S-boats were built for the opposite task. Fast, low and difficult to see at night, they could attack with 53.3-centimetre torpedoes and withdraw before heavier escorts could concentrate against them. Nine boats from the 5th and 9th Schnellboot flotillas made contact with the convoy.

The beach exercise brought together DUKWs, tank destroyers, landing craft, engineering vehicles and the tracking needed to move heavy loads over shingle. The equipment photographs below come from Slapton or from the exact ship types involved; where the photograph is only a period type image, the caption says so.

Naval History and Heritage Command gives 749 American dead or missing from the E-boat attack: 551 Army and 198 Navy. Historic England records 202 losses from LST-507 and 424 from LST-531. Other deaths came from the damaged ships and the water.

The loss mechanism was unusually cruel. Men were trapped below decks, burned by fuel fires, drowned, or died from exposure. Some life belts were worn around the waist rather than high under the arms. In the water, that could pitch an exhausted man face-down instead of supporting his head.

Friendly-fire deaths during the wider rehearsal are harder to reconstruct. The timing error on 27 April is documented, but the US Army's recent review states that the heavy naval bombardment did not strike Company G. This page therefore does not attach a precise friendly-fire death total to that episode.

The land-side chronology follows Stephen A. Bourque's 2024 US Army study of the 4th Infantry Division's D-Day preparation, which draws on Barton papers, division records and VII Corps material. It is particularly useful for the 27 April timing change and for separating the documented training failure from later versions of the friendly-fire story.

The naval attack is checked against Naval History and Heritage Command accounts and Historic England's protected-wreck records for LST-507 and LST-531. Those records provide the casualty accounting, cargo detail and physical evidence from the wreck sites. Photographic captions and rights are taken from the individual Wikimedia Commons file pages.