The wreck of HMS Thistle has been discovered in the North Sea, off south-western Norway. The British submarine had been missing for 83 years, since being sunk by a German U-boat during World War Two.
A Norwegian expedition to map seabed geology and biology from the research vessel GO Sars this spring had revealed an anomaly at a depth of 160m, with ROV-mounted cameras revealing it to be that of a submarine. Only now, however, following a second ROV dive, has imagery been produced to enable the Royal Navy to confirm its identity.
The surveys were part of the MAREANO project, which has been run since 2006 by Norway’s Institute of Marine Research (IMR), Geological Survey of Norway and Norwegian Mapping Authority.
The team had already come across four wrecks on the spring expedition when the Thistle mark showed up. Of the five, only a cargo ship called Azalea sunk in 1990 had been previously known about.
“It is not very often that I am in the video-room when new locations are being investigated, but on this particular occasion my curiosity was piqued well before the video rig was submerged in the water,” says senior engineer Kjell Bakkeplass.
“The similarity between wreck structures we had previously examined and this one was striking. After examining the wreck using a camera, we could quickly establish that it was a submarine. I checked if there were any submarines that were missing in the area and that could match this wreck.”
Two British submarines
Bakkeplass’s onboard research indicated that the submarine was likely to be a British vessel, but initially it seemed more likely to have been HMS Oxley, lost just before WW2, rather than wartime casualty HMS Thistle (N24), an 84m T-class submarine launched in October 1938.
The Thistle had joined the Royal Navy’s 2nd Submarine Flotilla, based at Dundee and Blyth, and in 1940, under the command of Lt Wilfrid Frederick Haselfoot, had been patrolling off Stavanger on the eve of an expected German invasion of Norway.
At around 4pm on 9 April, Thistle signalled that she had unsuccessfully fired six torpedoes at the surfaced U-4, leaving only two. She was ordered to move north to patrol off Skudenes, and no further contact was made.
It was later found that the U-boat, which had dived after the first Thistle torpedo passed ahead of her bow, had spotted the British vessel recharging her batteries at the surface at around 2am on 10 April.
She had fired two torpedoes and the second, from a distance of 250m, had struck home. HMS Thistle had gone down with the loss of all 53 crew.
“At that time, navigators used bearings and squares and not GPS as they do today,” says Bakkeplass. “This means that the position for the sinking was inaccurate.”
After the expedition, submarine experts suggested that HMS Thistle was the more likely option of the two, but it took more detailed images captured during an October MAREANO voyage to the Skagerrak to settle the matter – with the “small caveat that it is the Royal Navy that is responsible for the final identification,” as expedition leader Kyrre Heldal Kartveit pointed out.
“We used the ROV ÆGIR6000 for the dive,” he told Divernet. “This is a work-class research ROV, which was needed due to the strong currents along the Norwegian coast that made the dive very challenging. A smaller ROV would struggle – especially in this area.”
HMS Oxley remains to be located. The vessel had been sunk in error by another British submarine, again leaving 53 dead, though two of the crew had survived.
All the MAREANO wreck observations, also including two lost shipping containers and an aircraft engine, were reported to Stavanger Museum, which is responsible for wrecks found in the area.
Also on Divernet: Sub-hunter tracks down HMS Triumph off Greece, Greek wreck-hunter solves 1959 mystery, The O2 Rebreather Miracle, First freedivers visit ‘Great Escape’ sub, Tech divers untangle Perseus sub, Wreck Tour 55: HMS Umpire
