Located in the car park on the island of Garbh Eilean on the north side of the Kylesku Bridge in W Sutherland is a memorial cairn to the men of the XIIth Submarine Flotilla, who trained in Loch Cairnbawn, and names thirty-nine of their number who perished. Formed as the Experimental Submarine Flotilla, this initially comprised two-man chariots (or human-torpedoes) and, later, the slightly larger X-craft miniature submarines, with a crew of four. Both craft carried large explosive which were placed below the hulls of enemy ships. The chariots failed in an attack on the German battleship Tirpitz in 1942 and operations were transferred to the Mediterranean where considerable success was achieved against Italian warships. However, in 1943, further X-craft came to Loch Cairnbawn from Rothesay (on Bute) supported by the depot ship HMS Bonaventure. These succeeded in severely damaging Tirpitz taking her out of the war for six months.
Unveiled on 10th April 1993, the memorial commemorates the 50th anniversary of the formation of the flotilla. The memorial also expresses gratitude to the local people who protected the security of these top-secret operations: "they knew so much but talked so little".