The naval trawler is a concept for expeditiously converting a nation's fishing boats and fishermen to military assets.
[7] During the Second World War the Kriegsmarine operated trawlers as Vorpostenboot (outpost boats) and as weather ships; the Lauenburg was an example.
For the Second World War the Royal Norwegian Navy used six converted whalers and 22 other fishing vessels as minesweepers, and a further ten as patrol craft.
[9] The Royal Norwegian Navy also used a German naval trawler captured in April 1940 and put into service as HNoMS Honningsvåg.
Though Portugal was neutral or non-belligerent throughout the Second World War, a number of steel and wooden-hulled vessels were built there to trawler design for the Royal Navy.
Later, as Portugal became more closely involved with the western allies, Britain transferred a number of Isles-class trawlers to the Portuguese Navy as anti-submarine vessels.
[11] During the First World War, the Royal Navy operated 627 "Admiralty Trawlers" which had been purpose-built, purchased from foreign countries, or acquired as prizes.
In 1940 Lieutenant Richard Stannard was in command of the naval trawler HMT Arab when he won the Victoria Cross for his actions from 28 April to 2 May 1940 at Namsos in the Norwegian campaign.
Although employed with the Task Force on various other auxiliary duties, after the Argentine surrender the trawlers were able to sweep ten naval mines which had been successfully laid in Port Stanley harbour; eleven others had failed to deploy or had broken adrift.
[14] The US Navy generally favoured custom-built warships to civilian conversions, but in the first months of World War II the acute shortage of vessels for coastal defence and anti-submarine work led to the formation of a mosquito fleet.
Twenty steel-hulled and more than 40 wooden-hulled trawlers were commissioned as auxiliary minesweepers (AM designation), but confined to coastal waters and not rated for offensive or convoy escort duties.
A further 70 tuna clippers were called up as minesweepers (Amc designation), ten as harbour patrol craft (YP) and 50 as coastal transports (APC).
[15] The United States Coast Guard requisitioned ten Boston fishing trawlers for the Greenland Patrol.