Operation Gambit was a part ofOperation Neptune, the landing phase of the invasion of northern France (Operation Overlord) during theSecond World War. Gambit involved twoX class submarines (British midget submarines) marking the ends of the Anglo-Canadian invasion beaches. Using navigation lights and flags, the submarines indicated the western and eastern limits ofSword andJuno Beaches.X20 andX23 arrived in position on 4 June and due to the delay caused by bad weather, remained in position until4:30 a.m. on 6 June (D-Day) when they surfaced, erected the navigational aids, an 18 ft (5.5 m) telescopic mast with a light shining to seaward, a radio beacon and echo sounder, tapping out a message for theminelayers approaching Sword and Juno.
A similar operation had been offered to the USlanding forces to mark their beaches but this was declined. The team of CaptainLogan Scott-Bowden and Sergeant Bruce Ogden-Smith did investigateOmaha Beach for GeneralOmar Bradley, returning with a sand sample.[1] The submarines were at some risk of damage due to friendly fire and to avoid this, LieutenantGeorge Honour the captain ofX23 flew aWhite Ensign of the size more normally used by capital ships.[2]
