HMCS Ypres was one of twelve Battle-class naval trawlers constructed for and used by the Royal Canadian Navy (RCN) during the First World War. Named after the Second and Third battles of Ypres, the ship entered service in 1918, patrolling the east coast of Canada for submarine activity. Following the war, the ship remained in service with as a patrol and training ship. In 1938, the vessel recommissioned as a gate vessel, re-designated Gate Vessel 1, in service at Halifax, Nova Scotia. On 12 May 1940, the gate vessel was rammed and sunk in a collision with the British battleship HMS Revenge.