My father was in charge of the stern torpedo tube on the Stubborn, and was involved in the famous X-craft mission to the Fjiords. He never spoke about it except to say that it was "uncomfortable". From the account I got from the Sub museum in Pompey, that is a huge understatement. They were shelled, depth-charged etc and sank to the sea bed, where they stuck fast at some depth well below what their outer hull was designed to withstand. When they managed to get her up, she shot out of the water at about 75 degrees, and got hammered again, back down to the sea floor. Yet again, they managed to surface, and were lucky to be taken in tow by a fishing boat back to their depot in Northern Scotland.
He thought the sub was then beyond repair, and was towed out to the Irish sea to be used as a bomb target for the RAF. In fact, she was repaired, re-crewed, and sent out to the Pacific to sink a few Japanese ships before finally being deliberately sunk off malta to be used as an asdic training target. She is there still,a world famous dive wreck.
Roger