Operation Source was a series of attacks to neutralise the heavy German warships – Tirpitz, Scharnhorst and Lützow – based in northern Norway, using X-class midget submarines.
The attacks took place in September 1943 at Kaafjord and succeeded in keeping Tirpitz out of action for at least six months. The concept for the attack was developed by Commander Cromwell-Varley, with support of Max Horton, Flag Officer Submarines, and Prime Minister Winston Churchill.
The operation was directed from HMS Varbel, located in Port Bannatyne on the Isle of Bute. Varbel (named after Commanders Varley and Bell, designers of the X-Craft prototype) was the on-shore headquarters for the 12th Submarine Flotilla (midget submarines). It had been a luxury 88-bedroom hotel (the Kyles Hydropathic Hotel) requisitioned by the Admiralty to serve as the flotilla's headquarters. All X-craft training and preparation for X-craft attacks (including that on Tirpitz) was co-ordinated from Varbel.
Intelligence contributing to the attack on Tirpitz was collected and sent to the Royal Navy by the Norwegian resistance, especially brothers Torbjørn Johansen and Einar Johansen.
Attack
Six X-craft were used. X5, X6 and X7 were allocated the battleship Tirpitz, in Kåfjord. X9 and X10 were to attack the battleship Scharnhorst, also in Kåfjord. X8 was to attack the heavy cruiser Lützow in Langfjord. The submersibles were towed to the area by conventional submarines (HMS Truculent (X6) Syrtis (X9), Sea Nymph (X8), Thrasher (X5), Stubborn (X7), and Sceptre (X10)) and manned by passage crews on the way. Close to the target, the operation crews would take over.
X9, probably trimmed heavily by the bow in the heavy sea for the tow, was lost with all three crew on the passage when her tow parted and she suffered an abrupt plunge due to her bow-down trim.X8 (passage crew commanded by Lieutenant Jack Smart) developed serious leaks in her side-mounted demolition charges, which had to be jettisoned; these exploded, leaving her so damaged she had to be scuttled.