Historic raid ship’s watery grave found by sonar
THE last resting-place of an historic fast raiding vessel which featured in a 1951 war film has been pinpointed by sonar.
Motor Torpedo Boat (MTB) 539 was designed and built on the Menai Straits 75 years ago. It could travel at almost 50mph, driven by three large Packard V-12 petrol engines.
It was 75ft long and carried twin torpedo tubes on each side and an array of heavy machine guns, and it was the UK’s first all-aluminium Royal Navy boat.
In its brief role in 1951 film Appointment With Venus, starring David Niven and Glynis Johns, it played the part of a German E-boat.
But its light and wafer-thin aluminium, a product of the wartime aeroplane-building industry, also made it vulnerable, and when it was under tow and caught in a gale in the Irish Sea in 1952 one of its engines shook loose and smashed a hole in the hull.
The tow rope parted and the boat sank quickly, but no-one was aboard. MTB 539 now lies off Point Lynas, Anglesey, in 120ft of water.
The wreck has been surveyed using multibeam sonar by a team from Bangor University’s School of Ocean Sciences, who are mapping the seabed off the coast of Wales and will feature in the innovative O Dan y Dwr: Hidden Seascapes of Wales project.
MTB 539 was designed and built by air and marine engineering specialists Saunders Roe at their Beaumaris Fryars Bay yard, and marine engineer Victor Mills worked on it after joining the firm in 1945.
His son, Dave, has pieced together the vessel’s chequered history.
He told North Wales Live: “It was an experimental craft, and when my dad got a job there he was quite surprised to be working on it almost immediately.
“It was built from aluminium which Saunders Roe had experience of working on flying boats, so it was very light and was powered by three huge 1500-horsepower Packard engines.
“It was launched in about 1948 and went down to Portsmouth for trials, but had developed quite a few problems and was being towed back to Anglesey by an Admiralty tug.
“They had rounded Point Lynas, off the north-east coast of Anglesey, when they were caught in a storm and the engine shook off its mountings and punched a hole through the thin aluminium hull. The boat immediately sank.”
Dave added that MTB 539 was sitting on the sandy sea floor and had little damage. “The action of the tidal flow has polished the hull to a shiny finish,” he said.
Dr Michael Roberts, of the School of Ocean Sciences, has been heavily involved in the Seacams2 project and helped set up the O Dan y Dwr initiative, which features a collection of sonar-based images and information on submerged sites around Wales.
Much of the data and resultant imagery has been gathered from the university’s survey ship, Prince Madog, based at Menai Bridge.
Dr Roberts said: “We use a multibeam system which emits over 500 near-simultaneous sonar beams which bounce off the seabed to provide an image of what’s down there.
“We do know where the vast majority of shipwrecks in our waters are, with over 300 lying between Pembrokeshire and the Great Orme, however, the vast majority are either unknown or misidentified.”