WWII era minesweeper HMS Mercury identified in Irish Sea

British researchers have identified the wreck of the World War II minesweeper HMS Mercury. Although until recently the vessel resting at the bottom of the Irish Sea was thought to be an unidentified submarine.

During a recent expedition, the correct identification of HMS Mercury was made by a combined team of British researchers. It included marine archaeologists from Bournemouth University and scientists from Bangor University’s School of Ocean Sciences.

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The team carried out a comprehensive survey and used information from archives and documentation collected using multibeam sonar. High-resolution images and available information identified the wreck, which sank more than 80 years ago.

HMS Mercury

The trawler HMS Mercury was a steamer built for the London Midland Scottish Railway in 1934. The vessel measured 68 metres long and operated as a ferry on the River Clyde, travelling between Greenock, Gourock and Wemyss Bay.

After the outbreak of war in 1939. The Admiralty requisitioned the unit and incorporated it into the Royal Navy. From then on she began to function as a minesweeper. The unit’s fate came to an end in 1940, when HMS Mercury ran into a mine and sank.

The story of the sinking

The official list of warship losses stated that the minesweeper HMS Mercury sank after running into a mine of her own near the south coast of Ireland. However, as it turned out, the story is more complicated. New research at the National Archives has revealed that the incident took place near the Saltee Islands, near County Wexford. At 4.30pm on Christmas Day 1940, the minesweeper HMS Mercury attempted to clear an older British minefield.

The mine caught on the clearing equipment and came too close to the ship, then exploded under the stern. Though still floating, the minesweeper HMS Mercury was still potentially salvageable. A tug pulled it away towards Milford Haven. Unfortunately, the minesweeper was taking on water and as a result broke the towline and went to the bottom.

Fortunately, all the crew operating the minesweeper HMS Mercury were rescued. As a result of the incident, her commanding officer, Provisional Lieutenant Bertrand Palmer, was court-martialed for negligence.

Wreck identification programme

The identification of the wreck is part of an ongoing research programme to develop a detailed list of vessels lost in the Irish Sea. The project is being led by well-known wreck expert Dr Innes McCartney of Bournemouth University. As part of the research, the crew of Bangor University’s RV Prince Madog unit have investigated around 300 wrecks.

This highly innovative research project has resulted in many new discoveries dating back to both world wars. The identification of the minesweeper HMS Mercury is just one of many examples. – Dr McCartney said.