A shipwreck in the Irish Sea, previously thought to have been that of a submarine, has been identified as the World War II minesweeper HMS Mercury.
The discovery was made as part of a joint research project between maritime archaeologists at Bournemouth University and scientists at Bangor University’s School of Ocean Sciences.
The team used marine archives and high-resolution multibeam sonar data to identify the wreck, which has remained underwater for more than 80 years.
Built for the London Midland Scottish Railway in 1934, the 223ft-long paddle steamer originally served as a ferry on the River Clyde along a route between Greenock, Gourock, and Wemyss Bay.
Requisitioned by the Admiralty upon the outbreak of the war in 1939, HMS Mercury served as a minesweeper until the following year, when it was sunk during a routine operation.
The official list of losses of naval vessels during the war stated that Mercury was ‘sunk after damage by own mine south of Ireland’.
However, the story is more complicated than that. New research at the National Archives has revealed that the incident began near the Saltee Islands, off County Wexford, at 4.30pm on Christmas Day 1940, when Mercury was trying to sweep up an older British minefield.
A device snagged under her sweeping gear and was drawn too close to the ship, before exploding under her stern. Still afloat and potentially salvageable, Mercury was towed towards Milford Haven but sank two hours later after the towing cable parted under the strain of the slowly flooding ship.
Mercury’s entire crew was saved but her commander, Temporary Lieutenant Bertrand Palmer, was later court martialled for negligence.
The discovery is part of an ongoing research programme to compile detailed lists of ships lost in the Irish Sea and is led by Dr Innes McCartney of Bournemouth University. As part of the study, Bangor University’s research vessel Prince Madog has been used to survey some 300 wrecks.
‘This highly innovative research project has resulted in many new discoveries dating from both world wars, of which HMS Mercury is just one example,’ Dr McCartney said.
Dr Michael Roberts of Bangor University, who led the multibeam surveys, added: ‘These sunken vessels represent the sacrifices and efforts of citizens who were the “key” and “essential” workers of their time and it’s important that the final resting place of the vessels they were associated with are identified before it’s too late.’
‘We hope to secure additional funding to expand on this work and examine wrecks in other UK coastal regions before their remnants become unidentifiable due to degradation through natural marine processes.’