At the conclusion of WWI hostilities, the German High Seas Fleet was interned at the Royal Navy’s northern base at Scapa Flow, in the Orkney Islands of Scotland. On learning of the proposal to give the vessels to the victorious allies, the German commander – on 21st June 1919 – ordered the scuttling of the entire fleet.
Initially written off by the British Admiralty as being un-salvageable as far as future operational use was concerned, the rights were sold to an enterprising scrap-metal merchant, Ernest Cox. Despite having no prior experience in raising and disposing of sunken wrecks, Cox bid for the rights to salvage 27 of the 72 scuttled vessels.
Between 1924 and 1931, Cox’s team successfully raised some 32 of the sunken vessels; a feat that introduced new diving techniques and tools into the commercial diver’s arsenal … including the Cox’s gun, that proved to be an invaluable asset in the salvage operation.
Powered by a single explosive cartridge and capable of firing different bolt configurations through steel plates, it was useful in fitting patches to holes in hulls, or even to firing a hollow bolt that could be attached to a a surface-supplied air hose and replenish the atmosphere of sunken submarines until such time as the crew could be rescued.
Still in use several decades later, the Cox’s Gun played havoc with the ears – as well as the bowel movements of unsuspecting divers who happened to be in the vicinity when it was fired. (I speak from first-hand experience.)