Naval trawler

A naval trawler is a vessel built along the lines of a fishing trawler but fitted out for naval purposes. Naval trawlers were widely used during the First and Second World Wars. Fishing trawlers were particularly suited for many naval requirements because they were robust boats designed to work heavy trawls in all types of weather and had large clear working decks. One could create a mine sweeper simply by replacing the trawl with a mine sweep. Adding depth charge racks on the deck, ASDIC below, and a 3-inch (76 mm) or 4-inch (102 mm) gun in the bow equipped the trawler for anti-submarine duties.

Hmt Swansea Castle FL4393
First World War naval trawler, HMT Swansea Castle
Hmt Lancer FL14526
Second World War naval trawler, HMT Lancer


Armed trawlers were also used to defend fishing groups from enemy aircraft or submarines. The smallest civilian trawlers were converted to danlayers.

The naval trawler is a concept for expeditiously converting a nation's fishing boats and fishermen to military assets. England used trawlers to maintain control of seaward approaches to major harbors. No one knew these waters as well as local fishermen, and the trawler was the ship type these fishermen understood and could operate effectively without further instruction. The Royal Navy maintained a small inventory of trawlers in peacetime, but requisitioned much larger numbers of civilian trawlers in wartime. The larger and newer trawlers and whalers were converted for antisubmarine use and the older and smaller trawlers were converted to minesweepers

— A/S Trawlers[1]
A naval trawler's gun crew mans a 12-pounder (76-mm) Mk V gun on the forecastle
The Royal Navy during the Second World War A8588
HMT Northern Sky pitching and rolling at slow speed along her patrol lines. Operating off Iceland this trawler made the last attack of the Second World War on a U-boat.


In the aftermath of the First World War, the Belgian Corps de Marine purchased several British war surplus naval trawlers. They were operational during the Battle of Belgium (1940) and one of them, A4, evacuated a large quantity of the National Bank's gold reserves to Britain shortly before Belgium's surrender.


As with Portugal, the British Royal Navy had a number of trawler-type warships on order from Brazilian shipyards. With the declaration of war by Brazil against Germany in 1942 these vessels were transferred to the Brazilian Navy for anti-submarine and escort duties.[2]


The French Navy also made use of trawlers requisitioned from civilian use during wartime. In the Second World War 480 trawler type vessels were in service as auxiliary mine-sweepers and a further sixty as auxiliary patrol vessels.[3]


During the Second World War the Kriegsmarine operated trawlers as Vorpostenboot (outpost boats) and as weather ships; the Lauenburg was an example. It also used a large number of Kriegsfischkutter, trawlers built after the 24m long model "G" of the scientifically developed fishing cutter models (seven "Reichsfischkutter"-models A to- G), redesigned for naval uses such as anti-submarine warfare, but intended for conversion to fishing vessel after the war.


The Royal Indian Navy operated trawlers mostly for coastal defence; more than fifty Basset-class trawlers were ordered, but only twenty-two were completed with four more being destroyed before completion due to their shipyards being overrun by the Japanese in Burma. The remaining twenty-five were cancelled. They were used for coastal anti-submarine patrols and mine-sweeping duties.


As the Second World War progressed, Japan commandeered some fishing vessels for use as picket boats. To augment these, and to replace losses, the Imperial Japanese Navy also ordered a group of 280 picket boats, built on trawler lines but to Navy specifications. This was the No.1 class auxiliary patrol boat, though eventually only twenty-seven were completed.

New Zealand

main article, Minesweepers of the Royal New Zealand Navy.

During World War II the Royal New Zealand Navy operated thirty-five minesweepers, including twenty purpose-built naval trawlers (thirteen Castle class, three Bird class four Isles class), five converted fishing trawlers, and ten converted merchant vessels.


Norway had a large fishing and whaling fleet industry. For the Second World War the Royal Norwegian Navy made use of six converted whalers and twenty-two other fishing vessels as minesweepers and a further ten as patrol craft.[4] The Royal Norwegian Navy also made use of a captured German naval trawler, taken as prize in April 1940 and put into service as HNoMS Honningsvåg. After the occupation of Norway the Free Norwegian forces made use of fishing vessels for their clandestine Shetland bus operations in support of the Norwegian resistance.


Though Portugal was neutral throughout the Second World War, a number of steel and wooden-hulled vessels were built to trawler design for the Royal Navy. These Portuguese-class naval trawlers were delivered in 1942, but further construction was halted after protests from Nazi Germany. 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.[5]


Romania acquired three German KFK naval trawlers in 1943.[6]

United Kingdom

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. A further 1,456 trawlers were hired and operated, together with many other kinds of small vessel, by the Auxiliary Patrol.[7] Trawlers were mainly employed in minesweeping, anti-submarine patrols and as boom defence vessels.[8] Of the hired trawlers, 266 were lost while on active service.[7]

Before and during the Second World War, the Royal Navy ordered many naval trawlers to Admiralty specifications. Shipyards such as Smiths Dock Company that were used to building fishing trawlers could easily switch to constructing naval versions. As a bonus, the Admiralty could sell these trawlers to commercial fishing interests when the wars ended. Still, many were sunk during the war, such as HMT Amethyst and HMT Force. 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, Norway. HMT Arab survived 31 bombing attacks in five days.

More recently, during the Falklands War in 1982, the Royal Navy hired a flotilla of five trawlers from Kingston-upon-Hull, which were hastily converted to minesweepers, as the Ton-class minesweepers then in service were deemed to be unsuitable for the long voyage to the South Atlantic. Although employed with the Task Force on various other auxiliary duties, after the Argentine surrender, the trawlers were able to sweep 10 of the 21 naval mines which had been laid in Port Stanley harbour (the remaining mines failed to deploy or had broken adrift).[9]

United States

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 trawlers and more than forty wooden-hulled trawlers were commissioned as auxiliary minesweepers. (AM designation). These however were confined to coastal waters and not rated for offensive or convoy escort duties. A further seventy tuna clippers were called up as minesweepers (Amc designation), ten as harbour patrol craft (YP) and fifty as coastal transports (APC).[10] The United States Coast Guard requisitioned ten Boston fishing trawlers for the Greenland Patrol.[11]

Modern day

Some nations still use armed trawlers today for fisheries protection and patrol. The Indian Navy used naval trawlers for patrol duties during its involvement in the Sri Lankan civil war.[12] North Korea has been notoriously known for its use of armed trawlers as spy ships. The Battle of Amami-Ōshima was an incident in which the Japanese sank a North Korean naval trawler after a six-hour battle. Somali pirates have also commandeered trawlers and armed them for attacking freighters off the Horn of Africa. The action of 18 March 2006 is one example of pirate use of a naval trawler. The pirates used naval trawlers again at the action of 30 March 2010 and the action of 1 April 2010. One naval trawler was sunk and another was captured by the Seychelles Coast Guard and a US Navy frigate.[13]


The Wheelhouse, Hm Trawler Mackenzie Art.IWMART933

Wheelhouse of a naval trawler

A Wireless Operator, Hm Trawler James Hinneford Art.IWMART932

Wireless operator

The Engine Room, Hm Trawler Mackenzie Art.IWMART897

Engine room

The Stokehold, Hm Trawler Mackenzie Art.IWMART903

Stoker shovelling coal from a bunker

Cleaning the Gun, Hm Trawler Mackenzie Art.IWMART898

Cleaning the gun

Forward from the Wheelhouse, Hm Trawler Mackenzie- the figures are just about to slip the 'kite' used to sink the wire hawser to the required depths for sweeping Art.IWMART905

Slipping the "kite" which controls the mine sweeping depth

A Cook in the Galley, Hm Trawler Mackenzie Art.IWMART896

Cook in the galley

Cards in the Fo'c's'le, Hm Trawler Mackenzie Art.IWMART931

Cards in the fo'c's'le

Mail Day in the Fo'c'sle, Hm Trawler James Hinneford Art.IWMART900

Mail day

Trawler classes

See also


  1. ^ "A/S Trawlers".
  2. ^ Conway p417
  3. ^ Conway p279
  4. ^ Conway p381
  5. ^ Conway p67
  6. ^ Cornel I. Scafeș, Armata Română 1941-1945, RAI Publishing, 1996, p. 174.
  7. ^ a b Dittmar, F J; Colledge, J J. "World War 1 at Sea - Ships of the Royal Navy, 1914-1919 - AUXILIARY PATROL VESSELS, Part 1, Yachts to Trawlers". Gordon Smith. Retrieved 15 July 2016.
  8. ^ "World War One – The War At Sea - Auxiliary Patrol". National Museum of the Royal New Zealand Navy. Retrieved 15 July 2016.
  9. ^ Hoole, Rob (June 2007). "The Forgotten Few of the Falklands". Mine Warfare & Clearance Diving Officers' Association. Retrieved 15 July 2016.
  10. ^ Conway p152
  11. ^ Willoughby, Malcolm F. (1957). The U.S. Coast Guard in World War II. Annapolis, Maryland: United States Naval Institute. p. 100.
  12. ^ Hiranandani, G. M. (2010). Transition to Guardianship: The Indian Navy 1991-2000. Lancer International Incorporated. ISBN 9781935501268.
  13. ^ Peckham, Matt (17 November 2008). "Somali Pirates Plundering Trade Ships". PC World – via The Washington Post.


  • Chesneau, Roger (1980). Conway's All the World's Fighting Ships 1922-1946. ISBN 0-85177-146-7.
  • Lund, Paul; Ludlam, Harry (1971). Trawlers go to War. W. Foulsham. ISBN 978-0-572-00768-3.
  • Lund, Paul; Ludlam, Harry (1972). Trawlers go to War (paperback). New English Library. ISBN 0-450-01175-5.
  • Lund, Paul; Ludlam, Harry (1978). Out Sweeps! - The Story of the Minesweepers in World War II. New English Library. ISBN 978-0-450-04468-7.
  • McKee, Alexander (1973). The Coal-Scuttle Brigade : The splendid, dramatic story of the Channel convoys. New English Library. ISBN 978-0450013546.

External links

Action of 14 October 1918

The Action of 14 October was a naval engagement of the First World War when the Imperial German Navy submarine SM U-139 attacked the Portuguese civilian steamer São Miguel and the Portuguese Navy naval trawler NRP Augusto de Castilho in the Atlantic Ocean on 14 October 1918.

Belgian ship A4

Patrol vessel A4 (French: Patrouilleur A4) was a small Mersey-class naval trawler operated by Belgium during the Second World War. Originally built for the British Royal Navy, as HMS John Ebbs, the ship is notable for its role in evacuating Belgian gold reserves to England during the Battle of Belgium in May 1940. The success of the operation not only allowed the Belgian government in exile to fund its operations but deprived the German occupiers of an important asset to support their war effort. After the Belgian surrender, the vessel and its crew interned themselves in neutral Spain. Both crew and vessel were released in 1946 and A4 was scrapped soon afterwards.

Bird-class minesweeper

The Bird-class minesweeper was a naval trawler built to Admiralty specifications so it could function as a minesweeper. Three were built for the Royal New Zealand Navy. The vessels were also referred to as corvettes.

The Bird class evolved from the experimental minesweeping trawler HMS Basset, 1935, followed by HMS Mastiff, 1938, both built by Henry Robb Ltd. They were slightly larger and more powerful than these prototypes of what ultimately became the Isles class.

Castle-class trawler

The Castle-class minesweeper was a highly seaworthy naval trawler adapted for patrol, anti-submarine warfare and minesweeping duties and built to Admiralty specifications. Altogether 197 were built in the United Kingdom between 1916 and 1919, with others built in Canada, India and later New Zealand. Many saw service in the Second World War.

Greenland Patrol

The Greenland Patrol was a United States Coast Guard operation during World War II. The patrol was formed to support the U.S. Army building aerodrome facilities in Greenland for ferrying aircraft to the British Isles, and to defend Greenland with special attention to preventing German operations in the northeast. Coast Guard cutters were assisted by aircraft and dog sled teams patrolling the Greenland coast for Axis military activities. The patrol escorted Allied shipping to and from Greenland, built navigation and communication facilities, and provided rescue and weather ship services in the area from 1941 through 1945.

HMT Bredon (T223)

His Majesty's Trawler Bredon (Pennant Number T223) was a Hill class naval trawler that served as an anti-submarine escort trawler during the Second World War.

She was sunk by U-521 on 8 February 1943 while off the Canary Islands. Only 2 souls from her complement of 43 survived.

HMT Warwick Deeping

HMT Warwick Deeping (H136) was a naval trawler of the British Royal Naval Patrol Service during World War II, sunk off the Isle of Wight in December 1940.

List of ships at Dunkirk

This list consists of all major naval and merchant ships involved in Operation Dynamo, the evacuation of allied troops from the Dunkirk area from 26 May to 4 June 1940. The operation was administered by the British Admiralty with the Royal Navy providing the bulk of large vessels. They were accompanied by several other vessels of allied navies, most notably the French, as well as many merchant ships, some previously requisitioned and converted for naval use, and others called into service from their civilian roles due to the urgency of the situation. Hundreds of small privately owned craft, known as the Little Ships of Dunkirk, not listed here, were crucial in ferrying from the beaches to these larger vessels, whilst the majority of troops embarked directly at Dunkirk harbour.

List of shipwrecks in January 1916

The list of shipwrecks in January 1916 includes some ships sunk, foundered, grounded, or otherwise lost during January 1916.

List of shipwrecks in March 1916

The list of shipwrecks in March 1916 includes some ships sunk, foundered, grounded, or otherwise lost during March 1916.

List of shipwrecks in October 1915

The list of shipwrecks in October 1915 includes some ships sunk, foundered, grounded, or otherwise lost during October 1915.

Portuguese-class trawler

The Portuguese-class trawlers of World War II were naval trawlers, built in Portugal for the Royal Navy.

These vessels were built in several Portuguese yards, and offered by Portugal to the Royal Navy. This aid to the British war effort solicited protests by Nazi Germany, since, officially, Portugal was a neutral country.

After the war the ships were sold, most of them becoming mercantile vessels, some under the Portuguese flag. The former HMT Product went to the Royal Hellenic Navy.


T0 or T00 may refer to:

T0 space, a Kolmogorov space

HMNZS Wakakura (T00), a first World War Royal New Zealand Navy Castle class naval trawler

Same-day affirmation of a trade in financeand also :

a non-small cell lung carcinoma staging code for no evidence of primary tumor

T00 : Chambers County Airport FAA LID

a level on the tornado TORRO scale

USS Goldcrest (AM-80)

USS Goldcrest (AM-80), a steel-hulled commercial trawler built as MV Shawmut in 1928 by the Bethlehem Shipbuilding Corp., Quincy, Massachusetts, was acquired by the United States Navy from the Massachusetts Trawling Co. of Boston, Massachusetts, on 29 November 1940, and converted to a minesweeper. The ship was commissioned as a naval trawler at the Boston Navy Yard on 15 May 1941, Lt. Conrad H. Koopman in command.

USS Method (AM-264)

USS Method (AM-264) was an Admirable-class minesweeper built for the United States Navy during World War II and in commission from 1944 to 1945. In 1945, she was transferred to the Soviet Union and served in the Soviet Navy after that as T-276. The Soviets converted her into a naval trawler in 1948 and renamed her Purga.

USS Mirth (AM-265)

USS Mirth (AM-265) was an Admirable-class minesweeper built for the United States Navy during World War II and in commission from 1944 to 1945. In 1945, she was transferred to the Soviet Union and served in the Soviet Navy after that as T-277. The Soviets converted her into a naval trawler in 1948 and renamed her Musson.

USS Penetrate (AM-271)

USS Penetrate (AM-271) was an Admirable-class minesweeper built for the United States Navy during World War II and in commission from 1944 to 1945. In 1945, she was transferred to the Soviet Union and after that served in the Soviet Navy as T-280. The Soviets converted her into a naval trawler in 1948 and renamed her Taifun.

USS Rampart (AM-282)

USS Rampart (AM-282) was an Admirable-class minesweeper built for the United States Navy during World War II and in commission from 1944 to 1945. In 1945, she was transferred to the Soviet Union and after that served in the Soviet Navy as T-282. She was converted to a naval trawler in 1948 and renamed Shkval.

Vũng Rô Bay incident

The Vũng Rô Bay incident refers to the discovery of a 100-ton North Vietnamese naval trawler attempting to unload supplies and munitions on a beach in South Vietnam's Vũng Rô Bay on 16 February 1965. The incident spurred further United States Navy involvement in the Vietnam War.

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