An interview about the development and use of midget submarines in World War II by an unidentified speaker, probably Captain W. R. 'Tiny' Fell, a New Zealander who had a long career in the Royal Navy through both World Wars.
Fell was asked to build a human torpedo by Admiral Horton. The Queen Elizabeth had just been attacked by Italian human torpedoes in Alexandria Harbour, and they captured one and used it to develop a prototype.
They also developed a frogman suit to wear while manning it. The Royal Navy had not done any work on human torpedoes prior to this. They discovered that oxygen poisoning was a fatal problem for men working below thirty feet breathing pure oxygen.
It took six months to be ready for the first operation against the German battleship Tirpitz. The men sat astride the torpedo, and the explosive on the end could be detached and attached to the enemy vessel. The first operation against Tirpitz was unsuccessful as both human torpedoes were lost in a storm before they had reached Tirpitz.
They carried out seven successful operations, sinking two cruisers and blocking Tripoli. They also had successes in the Indian Ocean against the Japanese.
He also talks about X-craft, which were mini submarines. They had mines strapped to the side of them, which could be released when underneath an enemy target. These were more successful against Tirpitz - their charges went off and damaged the ship although both X-crafts deployed also sunk.
Towards the end of the war they worked with the Americans in the Pacific. Two Japanese cruisers had been moored to guard Singapore, and they succeeded in getting one of them as well as cable cutting. The midget submarines cut cables around Singapore, Vietnam and China, cutting off Japanese communications. The Italians had very similar craft, and he acknowledges they had several successes, including Alexandria. The Japanese also had some, but did not have any successes to his knowledge.