The eighth HMS Vanguard of the British Royal Navy was an Audacious-class central-battery ironclad battleship, launched in 1870. Vanguard — under the command of Captain Richard Dawkins, sailed out of Kingstown (now Dún Laoghaire) harbour on 27 August 1875 in company with three other ironclads, Warrior, Hector and Iron Duke. The ships were part of the First Reserve Squadron and were on a summer cruise around the Irish coast. The squadron — under the command of Admiral Tarleton, was en route to Queenstown (Cobh), County Cork where the cruise would finish. As they passed the Kish lightship, a heavy fog came down which restricted visibility to less than a ship's length.