Exercise Tiger

Exercise Tiger, or Operation Tiger, was the code name for one in a series of large-scale rehearsals for the D-Day invasion of Normandy, which took place on Slapton Sands or Slapton Beach in Devon. Coordination and communication problems resulted in friendly fire deaths during the exercise, and an Allied convoy positioning itself for the landing was attacked by E-boats of Nazi Germany's Kriegsmarine, resulting in the deaths of 946 American servicemen. Because of the impending invasion, the incident was under the strictest secrecy at the time and was only nominally reported afterward. As a result, Exercise Tiger has been called "forgotten."

The first practice assault took place on the morning of 27 April and was marred by an incident involving friendly fire. H-hour was set for 7:30 am, and was to be preceded by a live firing exercise to acclimatize the troops to the sights, sounds and even smells of a naval bombardment. During the landing itself, live rounds were to be fired over the heads of the incoming troops by forces on land, for the same reason. This followed an order made by General Dwight D. Eisenhower, the Supreme Allied Commander, who felt that the men must be hardened by exposure to real battle conditions. The British heavy cruiser HMS Hawkins was to shell the beach with live ammunition, from H-60 to H-30 (i.e. 6:30 to 7:00 am) giving the beachmasters half an hour to inspect the beach and declare it safe.

Several of the landing ships for that morning were delayed, and the officer in charge, American Admiral Don P. Moon, decided to delay H-hour for 60 minutes, until 8:30. This message was received by Hawkins, but not by a number of the landing craft, with the result that troops were landing on the beach at the same time as the bombardment was taking place. British Marines on one vessel recorded in its log book, the only log which has since been recovered from any of the boats, that men were being killed by friendly fire. "On the beaches they had a white tape line beyond which the Americans should not cross until the live firing had finished." But the American soldiers said they were going straight through the white tape line and were getting blown up.
On the day after the first practice assaults, early on the morning of 28 April, the exercise was blighted when a convoy of follow-up troops was attacked by nine German E-boats under the command of Korvettenkapitän Bernd Klug, in Lyme Bay.