The vessels were reasonable sea-boats, but lost speed badly in a seaway when the paddle boxes tended to become choked with water.

At the start of the First World War, it soon became clear that a large number of minesweepers would be required to keep coastal shipping routes free from naval mines that were laid at night by fast German minelayers.

Initially, requisitioned trawlers were used for the task, but they had too deep a draught to operate in some areas, and could be too slow to sever the mooring cables of the mines.

Late in 1914, the Admiralty hired a number of paddle steamers which were built to carry tourists to seaside resorts or on pleasure cruises.

Although unable to operate in rough seas, they were judged to be the best solution to the problem and a requirement was issued for a purpose-built class based on the PS Glen Usk, a Bristol pleasure steamer.