HMS/M A1 became the Royal Navy's first submarine casualty, being rammed whilst on exercise in the Eastern Solent by the mail steamer Berwick Castle. She sank in only 39 feet of water, with the loss of all hands.She was struck on the starboard side, near the conning tower, which led to the fitting of a second watertight hatch at the bottom of conning towers as an additional safety measure.18th March 1904 sunk by the Berwick Castle.April 1904, raised and re-commissioned.Since that Friday in 1904, more than 5,000 Royal Navy submariners have perished.

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