[3] For surface running, the boats were powered by two 12-cylinder Vickers[4] 1,200-brake-horsepower (895 kW) diesel engines, each driving one propeller shaft.

The next day, 8 October, L26 suffered an explosion in the battery compartment on board in Campbeltown Harbour, Scotland, which killed two and injured 10 crew.

[7] L26's commanding officer, Lieutenant-Commander John Hugh Lewis, was Court-martialled over the incidents, and was found guilty of stranding the submarine and failing to check L26's batteries for damage after the grounding.

He was severely reprimanded and dismissed from L26 by the court,[8] although a second hearing cleared him of blame for the explosion and re-instated him to command of L26.

[11] Beginning on 22 March 1941, the Royal Navy and Allies began deploying submarines off Brest, France to prevent the German battleships Gneisenau and Scharnhorst from leaving port.

Purchased by the Canadian government in 1946, L26 was sunk as a target for sonar testing off St. Margarets Bay, Nova Scotia on 25 September 1946.