In the late 1940s / early1950s a German E boat was purchased at Milford by George Brothers Engineering Ltd. Marine Engineer Neville Ledger and an apprentice Bill Davies began the long task of overhauling the engines and repairing all the controls, and making her seaworthy. This took 6 months to complete. An unforeseen problem at Milford was the power of the engines which caused the skipper sailing her from Milford to Swansea to lose control and land the vessel on a mud bank. By going full astern she was removed from the mud bank and re-entered the dock where further repairs were carried out. When they were completed she eventually made her way safley to Swansea, berthing in the South Dock on the left hand side of the lockgates as viewed from the River Tawe. I remember as a schoolboy going aboard her.

There was a lot of work to be done other than on the main engines i.e. accommodation, lighting, and the removal of anything left over from the war.  When all the repairs were completed she was locked out of the dock, having been sold for £20,000, and was making her way to Gibraltar, Spain or Africa (it was not certain what her final destination would be). Again, control of the vessel was lost and she struck the West Pier, causing damage to the hull. Neville Ledger was on the West Pier at 6 o' clock that morning to see her off,  and was able to jump aboard and remonstrate with the skipper who had been instructed to use only the centre engine when in confined waters. It nearly came to blows.

Repairs to the hull had to be carried out and, once completed, the boat was finally on her way. Apprentice Bill Davies, against the advice of Neville Ledger sailed with her, but the payment promised for his services was not forthcoming and he had to make his own way back home. Neville Ledger always thought the purchasers were a dubious bunch, and he proved to be right. 

The German Schnellboot ("E-boat") S 204 flying a white flag of surrender at the coastal forces base HMS Beehive, Felixstowe, Suffolk (UK), on 13 May 1945. The two German E-Boats S 204 and S 205 from the 4th Schnellboot-Flotilla were escorted in by ten British MTBs. On board one of S 205 was Rear Admiral Erich Breuning, who had been in charge of E-Boat operations and who signed the instrument of surrender. Note the black panther painted on the side of S 204 which had on board KKpt Kurt Fimmen (CO 4th Schnellboot-Flotilla) and KptLt Bernd Rebensburg (Ia Op/Operations  

Below the E Boat during repairs in South Dock Swansea 

Schnellboot-class Motor Torpedo Boat | World War II Database

Machinery, Three 20-cylinder 2,000hp Daimler-Benz MB501 Diesel engines. Crew -23. Armament, 2x533mm torpedo tubes (4xMk 8 torpedos), 1x37mm Flak 42 ... of Diesel engines also meant that the German torpedo boats did not have to fight off hostilities S-Boats (universally referred to by the British as "E-Boats")  

ww2 data base with their mature diesel technology the Germans had the perfect powerplant to drive these high-speed torpedo boats. Early versions utilised the 1,320-hp MAN diesel engine, but later the 2,000-hp 20 cylinder V-form Daimler-Benz became the standard engines on the S18-S25 series boats and, ultimately, by 1945, some engines were developing almost 2,500-bhp. The boats had a wedge on the stern that prevented the bow from rising as it accelerated so the guns fired more accurately. That technology is today used on the US destroyers.