Mystery of World War Two 'flying boat' wreck
A scuba diver says wreckage discovered off the Lincolnshire coast nine years ago belonged to a World War Two Sunderland flying boat.
Kevin Smith, from Cleethorpes, said it was one of the aircraft that were used against German U-boats in the Atlantic.
He said he was "baffled" as there were no records that one of the planes ever crashed in the North Sea.
The Pembroke Dock Heritage Centre said the find was "intriguing" but a mystery as to why the aircraft was there.
The wreckage was found by the French Navy in 2005, about 27 miles (45 km) off the coast of Mablethorpe.
Mr Smith, who has explored the submerged aircraft three times, had previously thought it was the remains of a Halifax bomber.
However, over the summer he said he examined the wreckage and identified four Bristol Pegasus engines which were consistent with a MK1 Sunderland.
Sunderland flying boats were stationed in the west at RAF Pembroke Dock and used in the Battle of the Atlantic.
He said: "It's got us baffled. But I can't believe they [flying boats] didn't come down the North Sea looking for submarines.
"We might never know."
John Evans, from the Pembroke Dock Heritage Centre, Pembrokeshire, said: "There were a number of Sunderlands that disappeared [during World War Two] but the location is very interesting.
"It could well be a war grave and if that's the case it's, 'look, don't touch'.
"We're told it definitely hasn't an undercarriage, [it's got] four engines. It's very likely to be a Sunderland."
Mr Evans speculated that the Sunderland could have been returning from an operation in Norway in 1940.
"There was terrific activity [at the time], who knows what was happening?" he said.
He hopes to find a serial number to help identify the aircraft next year.
- The Sunderland was an RAF-developed patrol bomber
- They were mainly used in the Atlantic to fight U-boats
- There are only three left intact in museums
- Germans nicknamed them "Flying Porcupines" because of their firepower
- In 2000, a sunken Sunderland was found off the coast of Wales