The Battle of May Island is the name given to the series of accidents that occurred during Operation E.C.1 in 1918. Named after the Isle of May, an island in the Firth of Forth, close by, it was a disastrous series of accidents amongst Royal Navy ships on their way from Rosyth in Scotland to fleet exercises in the North Sea. On the misty night of 31 January to 1 February 1918, five collisions occurred between eight vessels. Two submarines were lost and three other submarines and a light cruiser were damaged. 104 men died, all of them Royal Navy.