Halcyon minesweepers grew from sloop design

The Halcyon class shows how sloop development fed a specialist minesweeper program. The Royal Navy ordered twenty-two, although one was destroyed during construction. The twenty-one completed ships became its principal prewar minesweepers, using a cut-down development of the Grimsby-class sloop design. Experience with one small-warship type could therefore support another mission without starting from a blank sheet.