The Ton class were coastal minesweepers built in the 1950s for the Royal Navy, but also used by other navies such as the South African Navy and the Royal Australian Navy. They were intended to meet the threat of seabed mines laid in shallow coastal waters, rivers, ports and harbours, a task for which the existing ocean-going minesweepers of the Algerine-class were not suited. The design of the class drew on lessons learnt in the Second World War when it became apparent that minelaying in coastal waters was more effective than in the deep sea; the existing fleet minesweepers were not well suited to deal with this threat. Design started at the Naval Construction Department in Bath in 1947 and the first ship was ordered in September 1950; the class eventually numbered 119 vessels. The Ton-class served as patrol vessels in Borneo, Malaysia, Northern Ireland and Hong Kong. The minehunters played a significant role in the Suez Canal clearance after the Yom Kippur war. They also provided the backbone of the UK's Fishery Protection Squadron