Aminesweeper is a smallwarship designed to remove or detonatenaval mines. Using various mechanisms intended to counter the threat posed by naval mines, minesweepers keep waterways clear for safe shipping.[1]
The earliest known usage of thenaval mine dates to theMing dynasty.[2] Dedicated minesweepers, however, only appeared many centuries later during theCrimean War, when they were deployed by the British. The Crimean War minesweepers were rowboats trailinggrapnels to snag mines. Minesweeping technology picked up in theRusso-Japanese War, using agingtorpedo boats as minesweepers.
In Britain, naval leaders recognized before the outbreak ofWorld War I that the development of sea mines was a threat to the nation's shipping and began efforts to counter the threat.Sir Arthur Wilson noted the real threat of the time was a blockade aided by mines and not an invasion. The function of the fishing fleet's trawlers with their trawl gear was recognized as having a natural connection with mine clearance and, among other things,trawlers were used to keep theEnglish Channel clear of mines.[3] A Trawler Section of theRoyal Navy Reserve became the predecessor of the mine sweeping forces with specially designed ships and equipment to follow. These reserve Trawler Section fishermen and their trawlers were activated, supplied with mine gear, rifles, and uniforms, and paid as the first minesweepers.[4] The dedicated, purpose-built minesweeper first appeared duringWorld War I with theFlower-class minesweeping sloop. By the end of the war, however, naval mine technology had grown beyond the ability of minesweepers to detect and remove mines.[5]
Minesweeping made significant advancements duringWorld War II. Combatant nations quickly adapted ships to the task of minesweeping, including Australia's 35 civilian ships that becameauxiliary minesweepers.[6] Both Allied and Axis countries made heavy use of minesweepers throughout the war. Historian Gordon Williamson wrote that "Germany's minesweepers alone formed a massive proportion of its total strength, and are very much the unsung heroes of theKriegsmarine."[7] Naval mines remained a threat even after the war ended, and minesweeping crews were still active afterVJ Day.[8]After the Second World War, Allied countries worked on new classes of minesweepers ranging from 120-ton designs for clearingestuaries to 735-ton oceangoing vessels.[9] TheUnited States Navy even used specializedmechanized landing craft to sweep shallow harbors in and aroundNorth Korea.[10]
As of June 2012[update], theU.S. Navy had four minesweepers deployed to the Persian Gulf to address regional instabilities.[11][12] The Royal Navy also has four minesweepers stationed in the Persian Gulf as part of the9th Mine Counter-Measures Squadron.
Minesweepers are equipped with mechanical or electrical devices, known as "sweeps", for disabling mines. The modern minesweeper is designed to reduce the chances of it detonating mines itself; it issoundproofed to reduce itsacoustic signature and oftenconstructed using wood,fiberglass, ornon-ferrous metal, or isdegaussed to reduce itsmagnetic signature.[13]
Mechanical sweeps are devices designed to cut the anchoring cables of moored mines, and preferably attach a tag to help the subsequent localization and neutralization. They are towed behind the minesweeper and use a towed body (e.g.,oropesa,paravane) to maintain the sweep at the desired depth and position. Influence sweeps are equipment, often towed, that emulate a particular ship signature, thereby causing a mine to detonate.
There are two modes of operating an influence sweep: MSM (mine setting mode) and TSM (target simulation mode or target setting mode). MSM sweeping is founded on intelligence on a given type of mine, and produces the output required for detonation of this mine. If such intelligence is unavailable, the TSM sweeping instead reproduces the influence of the friendly ship that is about to transit the area. TSM sweeping thus clears mines directed at this ship without knowledge of the mines. However, mines directed at other ships might remain.[14][15]
The minesweeper differs from aminehunter; the minehunter actively detects and neutralizes individual mines. Minesweepers are in many cases complementary to minehunters, depending on the operation and the environment; a minesweeper is, in particular, better suited to clearing open-water areas with large numbers of mines. Both kinds of ships are collectively calledmine countermeasure vessels (MCMV), a term also applied to a vessel that combines both roles.
