Quiet loch where Navy plotted attack on enemy warship
Fairlie’s research team played a major part in disabling the powerful German battleship Tirpitz that posed an “extreme threat” to North Atlantic and Russian Convoys.
Lying protected from air attack in a Norwegian fjord, but able to go to sea at any time, Tirpitz required the Navy to keep many of its own scarce battleships ready to react – some in Scapa Flow off Orkney.
Author John Riddell told The Sunday Post: “She could annihilate a convoy with the size of her guns and they decided she had to be put out of action.”
He writes: “The Royal Navy had developed its own version of a small submersible in the form of a midget submarine known as an X-craft.
“The plan was to use the X-craft to enter the fjord, make their way submerged to the battleship, and then place time-delayed explosive charges below her hull before retreating seaward. To do this, an asdic able to measure distance above the transducer was required, and the task was given to the scientists at Fairlie.
“The resulting Type 151 asdic had a very narrow beam and was mounted on top of the submarine’s casing. This enabled the X-craft’s commander to determine when his boat with its explosive charges was directly under the target and the charges could be released for later detonation.”
The X-craft crew was also trained in Scotland, with the Navy training the mini submariners in the icy lochs of the west coast.
Riddell added: “To assist in passing below or through the anti-submarine nets protecting the battleship, a depth-determining asdic – the modern echo sounder – was designed and installed.
“The X-craft attack on Tirpitz took place in September 1943 and succeeded in causing enough damage to reduce her immediate threat to the convoys.”