A net laying ship, also known as a net layer, net tender, gate ship or boom defence vessel was a type of naval

auxiliary ship An auxiliary ship is a naval ship designed to support combatant ships and other naval operations. Auxiliary ships are not primary combatant vessels, though they may have some limited combat capacity, usually for purposes of self-defense. Auxil ...

. A net layer's primary function was to lay and maintain steel anti-torpedo or anti-submarine nets. Nets could be laid around an individual ship at anchor, or around

harbor A harbor (American English), harbour (British English; see spelling differences), or haven is a sheltered body of water where ships, boats, and barges can be docked. The term ''harbor'' is often used interchangeably with ''port'', which is a ...

s or other

anchor An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek ἄ� ...

ages. Net laying was potentially dangerous work, and net laying seamen were experts at dealing with blocks, tackles, knots and splicing. As

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

progressed, net layers were pressed into a variety of additional roles including salvage, troop and cargo transport, buoy maintenance, and service as

tugboat A tugboat or tug is a marine vessel that manoeuvres other vessels by pushing or pulling them, with direct contact or a tow line. These boats typically tug ships in circumstances where they cannot or should not move under their own power, su ...

US Navy

1930s

War Plan Orange War Plan Orange (commonly known as Plan Orange or just Orange) is a series of United States Joint Army and Navy Board war plans for dealing with a possible war with Japan during the years between the First and Second World Wars. It failed to for ...

, the pre-WW2 US plan for war with Japan, anticipated that

Pearl Harbor Pearl Harbor is an American lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. It was often visited by the Naval fleet of the United States, before it was acquired from the Hawaiian Kingdom by the U.S. with the signing of the R ...

would be too small for the US Navy fleet that would be amassed in Hawaii. Orange anticipated the construction of a large anchorage in

Lahaina Roads Lahaina Roads, also called the Lahaina Roadstead, is an anchorage in the ʻAuʻau Channel lying off the town of Lahaina on the island of Maui in the Hawaiian archipelago and U.S. state of Hawaii. It lies in the lee of the West Maui Mountai ...

between the islands of Maui, Lānaʻi, and Molokaʻi. Construction would consist of massive nets and minefields to protect the anchored ships. Ultimately four large netlayers would be laid down just before and after the attack on Pearl Harbor: USS ''Monitor'' (AN-1), USS ''Montauk'' (AN-2), USS ''Osage'' (AN-3), and USS ''Saugus'' (AN-4). It turned out that these ships were not needed. First, dredging significantly enlarged the anchorages in Pearl Harbor. Second, the mobility of aircraft carrier warfare made the large Lahaina Roads anchorage concept obsolete, though smaller nets would still be needed for the entrance channels at advanced bases such as the

Majuro Majuro (; Marshallese: ' ) is the capital and largest city of the Marshall Islands. It is also a large coral atoll of 64 islands in the Pacific Ocean. It forms a legislative district of the Ratak (Sunrise) Chain of the Marshall Islands. The ato ...

and

Ulithi Ulithi ( yap, Wulthiy, , or ) is an atoll in the Caroline Islands of the western Pacific Ocean, about east of Yap. Overview Ulithi consists of 40 islets totaling , surrounding a lagoon about long and up to wide—at one of the larges ...

atolls. Third, new technology resulted in lightweight nets that could be handled by smaller vessels. The four large netlayers would be converted to carry and launch amphibious vehicles under the hull classification Landing Ship, Vehicle (LSV).Friedman, 2002, pp 178-179

1940s

Small net layers initially received the

hull classification The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration (NOAA) use a hull classification symbol (sometimes called hull code or hull number) to identify their ships by type and by ind ...

symbol Yard Net Tenders (YN) but 77 were later reclassified as Auxiliary Net Layer Ships (AN). These vessels had two prominent steel "horns" on the bow, used in laying nets. Another 24 vessels which held the (YN) symbol were impressed tugs rather than specially-built craft, and so these were redesignated as Net Tender Tugs (YNT). The 77 small Auxiliary Net Layers were built in three classes. The first 32, the ''Aloe''-class, were all launched in 1940 (before the attack on

) and were built of steel. Due to the chronic shortage of steel during the war, the next 40, the ''Ailanthus''-class, were built of wood. The last 15, the ''Cohoes''-class, laid down in 1944 and 1945, were again constructed of steel. These vessels served in all theatres of war but particularly in the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

. Many of the ships were decommissioned after the war, but some continued in service for several more decades. Net layers were eventually made redundant by advances in underwater detection technology. There were also at least 43 craft that were classed as Net Gate Craft (YNG); many were simply powered barges.

British and Commonwealth

Referred to as “boom defence vessel". * Bar-class boom defence vessel *

Net-class boom defence vessel The Net class were a class of boom defence vessels of the Royal Navy and Royal Australian Navy during World War II. Ships Of the eleven ships of the class ten were built in shipyards in northern England and Scotland, while the eleventh was built i ...

Gallery

File:Royal Navy Vessels Maintain the Boom Defence at Scapa Flow, Scotland, May 1943 A16572.jpg, The boom defence net at Scapa Flow being towed into position by two

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...

boom defence vessels in 1943. File:The Royal Navy during the Second World War A16583.jpg, At Scapa Flow, a Royal Navy net laying vessel prepares to lay an anti-submarine net, which is 900 feet (275 metres) long, weighs over 40 Imperial tons (41 tonnes) and could be laid in 4 minutes. File:The Royal Navy during the Second World War A17161.jpg, HMS ''Rogate'', a Royal Navy "gate vessel" designed to open and close the boom and nets at

Portsmouth Portsmouth ( ) is a port and city in the ceremonial county of Hampshire in southern England. The city of Portsmouth has been a unitary authority since 1 April 1997 and is administered by Portsmouth City Council. Portsmouth is the most dens ...

Harbour during World War II. File:HMCS Ypres E-35756.jpg, HMCS Ypres was a Battle class trawler used by the

Royal Canadian Navy The Royal Canadian Navy (RCN; french: Marine royale canadienne, ''MRC'') is the naval force of Canada. The RCN is one of three environmental commands within the Canadian Armed Forces. As of 2021, the RCN operates 12 frigates, four attack submar ...

as a gate vessel. She was sunk in a collision with a battleship in May 1940. File:USS TEREBINTH (AN-59).jpg, The US Navy wooden Net Tender, USS ''Terebinth'' (AN-59) in wartime camouflage. File:HMAS Kangaroo SLV AllanGreen.jpg, HMAS Kangaroo, a

Bar class boom defence vessel The Bar class were a class of boom defence vessels of the Royal Navy, Royal Australian Navy and South African Navy during World War II. Ships Royal Navy * HMS ''Barbain'' (Z01) * HMS ''Barbarian'' (Z18) * HMS ''Barbastel'' (Z276) * HMS ''Barbe ...

of the

Royal Australian Navy The Royal Australian Navy (RAN) is the principal naval force of the Australian Defence Force (ADF). The professional head of the RAN is Chief of Navy (CN) Vice Admiral Mark Hammond AM, RAN. CN is also jointly responsible to the Minister of ...

in 1947. File:Montauk LSV-6.jpg, USS ''Montauk'' after completion of her LSV conversion (mostly internal).

References

Citations

Sources

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External links

World War II Net Tenders
Navsource Online.
Photos of HMNZS Endeavour; Antarctic support ship, ex-US netlayer
{{DEFAULTSORT:Net Laying Ship Auxiliary gateship classes