In the early days of the twentieth century the simple contact mine was becoming the cheap weapon of choice for many navies. Countering this threat eventually fell to the the humble trawler - the similarity between trawling for fish and trawling for mines having quickly been realised. By 1916 however, the Admiralty was facing a famine of commercially available trawlers - so they went into the trawler building business. By the time the Armistice was signed, the RNR Trawler Section, originally a little force of 1200 men and 150 vessels for sweeping UK waters, had expanded to a massive 39,000 men, manning more than 700 vessels at home and abroad. This volume traces the histories of those Admiralty built vessels which started life as humble minesweepers but soon became the jack of all trades in two World Wars and beyond. Includes details of displacement, engines, armament, Admiralty no, port registration etc.