- Author
- Gregory, Mackenzie J.
- Subjects
- Ship histories and stories, WWII operations
- Tags
-
- RAN Ships
- None noted.
- Publication
- December 1997 edition of the Naval Historical Review (all rights reserved)
One of the best kept secrets of the Royal Navy during WW II was the capture of a Type VII C Submarine, U-Boat 570, and her subsequent commissioning with a British crew as H.M.S. Graph.
It happened in the North Atlantic on the 27th of August, 1941.
A British Hudson aircraft, unknown to the U-Boat, had sighted her as she dived about 80 miles south of Iceland. The aircraft dropped smoke markers, and made a sighting report – another Hudson, two hours later found the same U-Boat surfacing almost directly below it.
The U-Boat Captain had been lax in not searching with his air periscope prior to giving the order to surface.
Before U-570 could again dive to a safe depth, Squadron Leader J. Thompson’s aircraft had surrounded it with depth charges.
In the U-Boat, lights failed, instruments were damaged, and water entered up forward, some batteries were destroyed, and on board panic ensued as the crew realised the real danger of chlorine gas being generated within the Boat.
To quote the U-Boat Captain “We dropped lower, how low we did not know as our instruments were no longer functioning. We only knew sooner or later the point would be reached when the surrounding water pressure would crush the Boat. In that situation the only course was to blow out the ballast tanks immediately with compressed air.
I gave the order for this and brought the Boat to the surface. The Boat was no longer fit to submerge and hence robbed of its effective strength – on the surface we could not escape the aircraft which kept contact with us and was later relieved by yet another aircraft, until the arrival of the first Patrol Boat. If we attempted to escape we could not even know in what direction we were going as the depth charge attack had destroyed our compass installation. I then decided to scuttle the boat.”
It certainly was not U570’s day – they could only destroy secret papers, and the coding machine which was thrown overboard. They were then surrounded by a Destroyer and Patrol Boats, and gunfire wounded 6 of the U-Boat crew and prevented them from scuttling their submarine.
She was towed away and then beached off Thorlakshafn on the South coast of Iceland. On the 30th of August 1941, 4 Submariners, a Sub-Lieutenant, a Petty Officer, and 2 Sailors flew to Iceland to make a detailed examination of U-Boat 570. By the 5th of September, she was taken off Red Beach near Thorlock, and towed into Hvalfjord, and made ready for the crossing to England.
The British compiled a Top Secret document that dealt with U570 and her capture.
The British lost little time in integrating the U-Boat into the British Fleet, she was commissioned under the name H.M.S. “Graph” and assigned as an experimental Boat to the 3rd Submarine Flotilla with Lieutenant Peter Marriott appointed as her Captain. The British crew found she had a narrow and uncomfortable interior when compared to British submarines in which they had previously served, but from a technical viewpoint the German submarine yielded a rich vein of golden information.
Ship building engineers were amazed to find that the pressure hull was made of steel plates 20.5mm in thickness, that withstood water pressure at a depth of 150 meters or greater. The British adjusted their depth charge priming deeper than before, to 200 and up to 300 meters.
It was a year before Graph started on her first operational patrol, on the 8th of October 1942. On the 21st of October U-333 was close to the North Spanish coast. She was limping home after an almost fatal encounter with the Corvette Crocus; off Freetown, West Africa, and had been reported sunk by the Captain of Crocus; who was to be decorated with a D.S.C., for this and other actions in which he had been involved.
Graph picked up U-333, and fired 4 torpedoes, all of which were avoided by Peter Cremer in U-333. Marriott in Graph picked up a series of loud continuous noises on his underwater listening gear, after hearing his torpedoes explode. He assumed that the German Boat was destroyed, and reported accordingly to the Admiralty.
In 1980, Peter Cremer only one of three senior U-Boat Commanders to survive the war, was looking through Marriott’s war time log book, and suddenly realised that it was Graph, the former U-570, a sister Boat to his old U-333 that had almost torpedoed him back in 1942. Twice had U-333 been reported to the Admiralty as sunk, and finally, after Cremer had taken command of a new Electric Boat, on the 31st of July 1944, his old love U-333, became the first victim of the new ahead throwing weapon ‘Squid’