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{{Short description|Mechanical device that is used to adjust the tension of a rope}}
{{Other uses}}
{{More citations needed|date=November 2023}}
[[File:Winch.PNG|thumb|Self-tailing winch on a sailboat. A [[Sheet (sailing)|sheet]] line runs from the sail (left, not shown) behind the winch to a [[Block (sailing)|block]] (lower right, not shown) and only from there back to the winch (lower part). The handle is detachable to ease line handling.]]
[[File:Front of a MAN fire engine with winch and shackles.jpg|thumb|Front of a [[MAN SE|MAN]]-based [[fire engine]] with a built-in winch, e.g. for towing damaged cars after an accident]]
A '''winch''' is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the [[tension (physics)|tension]] of a [[rope]] or [[wire rope]] (also called "cable" or "wire cable").

In its simplest form, it consists of a [[Bobbin|spool]] (or drum) attached to a hand [[crank (mechanism)|crank]]. Traditionally, winches on ships accumulated wire or rope on the drum; those that do not accumulate, and instead pass on the wire/rope (see yacht photo above), are called [[Capstan_(nautical)|capstans]]. Despite this, sailboat capstans are most often referred to as winches.  Winches are the basis of such machines as [[tow truck]]s, [[steam shovel]]s and [[elevator]]s. More complex designs have [[gear]] assemblies and can be powered by electric, [[hydraulic]], [[pneumatic]] or [[internal combustion]] drives. It might include a [[solenoid brake]] and/or a [[Mechanical brake stretch wrapper|mechanical brake]] or [[ratchet (device)|ratchet and pawl]] which prevents it unwinding unless the [[pawl]] is retracted. The rope may be stored on the winch. When trimming a line on a [[sailboat]], the crew member turns the winch handle with one hand, while tailing (pulling on the loose tail end) with the other to maintain tension on the turns. Some winches have a "stripper" or cleat to maintain tension. These are known as "self-tailing" winches.<ref>Mark Smith. The Annapolis Book of Seamanship. 1999 Simon & Schuster</ref>

==History==
[[File:Treuil de traction et timonerie d'un chalutier.jpg|thumb|Winch used on a fishing boat to bring in nets]]
The earliest literary reference to a winch can be found in the account of [[Herodotus of Halicarnassus]] on the [[Greco-Persian Wars|Persian Wars]] (''[[Histories (Herodotus)|Histories]]'' 7.36), where he describes how wooden winches were used to tighten the cables for a [[pontoon bridge]] across the [[Hellespont]] in 480&nbsp;BC. Winches may have been employed even earlier in [[Assyria]]. By the 4th century BC, winch and pulley [[Hoist (device)|hoists]] were regarded by [[Aristotle]] as common for architectural use (''[[Mechanics (Aristotle)|Mech]]''. 18; 853b10-13).<ref>J. J. Coulton, "Lifting in Early Greek Architecture," ''[[The Journal of Hellenic Studies]]'', Vol. 94. (1974), pp. 1-19 (12)</ref>

The yacht ''[[Reliance (yacht)|Reliance]]'', American defender of the 1903 [[America's Cup]], was the first racing boat to be fitted with modern winches below decks. The ''Reliance's'' competitors relied on muscle power using topside mounted [[capstan (nautical)|capstan]]s and [[windlass]]es, which would soon be replaced in most applications by winches, including on [[fishing boat]]s, where they are used to bring in the [[fishing net]]s.

==Other applications ==
[[File:Flat Bed Tow Truck.jpg|thumb|Winching a car onto a tow truck]]

===Vehicle recovery===
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The main feature that legally distinguishes a [[tow truck]] from a conventional [[truck]] in many jurisdictions is the presence of a winch, which is used to either extract disabled or immobilized vehicles, or to load them onto flatbed/tilt and load type tow trucks. These may be electrically or hydraulically powered from a [[power take-off]], and is wound with a wire cable and equipped with a hook. [[Snatch block]]s may be used to change direction or increase the pulling power and a variety of specialized hooks may be attached to the main hook, including hooks which attach to specific parts of the car. J-hooks, which look somewhat like blunt meat hooks are used to hook around axles. Mini-J hooks can be used if there is a tow loop provided, and R and T hooks are designed to hook into slots cut by the manufacturer in the underside of the frame on many cars. Axle straps may also be used, when there are few other places to attach.

===Off-road vehicles===
[[Off-road vehicles]] may be equipped with recovery tools such as winches on the front and back bumpers, usually mounted to a [[Bullbar|winch bar]] or frame mounted metal bumper. Less commonly it is mounted on a specialised metal plate "hidden winch mount" behind the vehicle's stock bumper, this is referred to as a "hidden winch" as the hook and fairlead hides behind a flip-up front number plate, the winch itself is not visible.<ref>{{Cite web |title=An epidemic of hidden winch mounts |url=https://www.exploringoverland.com/overland-tech-travel/2022/5/29/an-epidemic-of-hidden-winch-mounts?format=amp |access-date=2023-08-28 |website=www.exploringoverland.com}}</ref><ref>{{Cite web |last=Johnson |first=Mike |title=Winch License Plate Mounts for Staying Legal |url=https://www.roundforge.com/articles/winch-license-plate-mounts/ |access-date=2023-08-28 |website=Roundforge |language=en}}</ref> The snubbing winch is used to pull vehicles out of mud, snow, sand, rocks, and water, and to pull vehicles through or over obstacles. The winch is made of cable made up of a braided synthetic rope, or a steel cable wrapped around a motorized drum.  Each is controlled electronically, allowing the operator to control the winch speed.<ref>{{Cite web|url=https://adventure.howstuffworks.com/outdoor-activities/off-roading/off-road-vehicles7.htm#:~:text=This%20is%20known%20as%20%22recovery,to%20spool%20up%20the%20line.|title = How Off-road Vehicles Work|date = 5 October 2009}}</ref> Modern vehicles typically use [[Warn Industries|electric winches]] running off the car's 12V starter or 24V secondary battery. The winch is either controlled with a detachable cable, a button inside the car or wireless remote. Older vehicles may have a [[Power take-off|PTO]] winch, controlled via the car's [[Transmission (mechanical device)|transmission]], a secondary [[clutch]] maybe used so the vehicle does not need to be moving while winching. Some winches are powered by the pressure generated in the [[Power steering|hydraulic steering system]]. The [[Jack_(device)#Farm_jack|high lift jack]] or [[come-along]] is used for manual winching.

===Aircraft use===
[[File:Bamberg-Breitenau airfield (04) (cropped).jpg|thumb|Glider winch. Winch spool can be seen on the side of the truck, while cables to the right of the image are attached to the glider(s) being launched]]
[[File:EHI CH-149 Cormorant (EH-101 Mk511), Canada - Air Force AN0681528.jpg|thumb|[[RCAF]] [[CH-149 Cormorant]] rescue helicopter, with rescue team on winch]]
[[Glider (sailplane)|Gliders]] are often launched using a winch mounted on a trailer or heavy vehicle. This method is widely used at many European gliding clubs, as an inexpensive alternative to aerotowing. The engine is usually a gas/petrol, LPG or [[diesel engine|diesel]], though [[hydraulic fluid]] engines and [[electrical motor]]s are also used. The winch pulls in {{cvt|1000|to|1600|m}} of high-tensile steel wire or a synthetic fibre cable, attached at the other end to the glider. The cable is released at a height of about {{cvt|400|to|700|m}} after a short, steep climb.<ref name="Piggott">{{cite book|last= Piggott|first= Derek|title= Understanding Gliding|publisher= Morrison & Gibb Ltd, London & Edinburgh|year=1977|isbn = 0-7136-1640-7}}</ref>

[[Search and Rescue]] [[helicopters]] are often equipped with winches to avoid having to get the helicopter dangerously close to obstacles, or into ocean troughs, allowing rescue teams to be lowered and evacuees to be extricated while the helicopter [[Hover (helicopter)|hovers]] overhead. Helicopter winches are also used for [[heli-logging]] and for airlifting oversized cargo, such as vehicles and other aircraft, although the winch in these cases is only used to reduce the hazards to flying with an loose cable hanging below the helicopter.

Stationary balloons, such as the [[barrage balloon]]s used during the [[Second World War]] to discourage marauding aircraft, and the [[Kite balloon]]s used during the [[First World War]] for artillery spotting are usually tethered with a winch, which can be used to lower the balloon, either to relocate it, or to bring it down quickly to prevent it being shot down by enemy aircraft. Larger man carrying kites often used winches to raise and lower them.

Towed gunnery targets, used to train [[Anti-aircraft warfare|anti-aircraft gunners]], and both [[fighter aircraft|fighter]] pilots and aircraft gunners, are run out behind the target tug aircraft for practice, and winched in for take-off and landing.

Before advances were made in antennas in the 1950s, radio aerials were quite long, and needed to be winched out for use, and winched back in for landing. Failure to do so would then damage the aerial, as happened to [[Amelia Earhart]] on one of the legs of her last flight.

===Theatre===
[[File:wakeskate winch.jpg|thumb|[[Wakeboarding]] winch which pulls the rider forward as the rope is wound in]]
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Winches are frequently used as elements of backstage mechanics to move [[Theatrical scenery|scenery]] in large theatrical productions. They are often embedded in the stage floor and used to move large set pieces on and off.

===Wakeskate winch===
{{unreferenced section|date=November 2023}}
Wakeskate winching is a sport where a person on a waterski or snowboard is propelled across the water with a winch. The winch consists of a gas-powered engine, spool, rope, frame, and sometimes a simple transmission. The person being towed walks (or swims) away from the winch, while extending the rope. When the winch is engaged, it pulls the boarder in at a speed ranging from {{convert|25|to|40|km/h|mph}}. The winch may be mounted to a vehicle, set into the ground by stakes, or tied to a tree. The cable may also be run through pulleys mounted offshore so that it pulls the person away from where the winch is located, and multiple pulleys may be used to multiply the force applied by a small but high revving motor instead of using a transmission.

==Winch types==
===Lever winch===
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Lever winches are winches that use self-gripping jaws instead of spools to move rope or wire through the winch. Powered by moving a handle back and forth, they allow one person to move objects several tons in weight.

===Snubbing winch===
This is a vertical spool with a ratchet mechanism similar to a conventional winch, but with no crank handle or other form of drive.<ref>Maritime Industry Dictionary definition: [http://www.m-i-link.com/dictionary/default.asp?term=snubbing+winch m-i-link.com] {{Webarchive|url=https://web.archive.org/web/20101229070736/http://m-i-link.com/dictionary/default.asp?term=snubbing+winch |date=2010-12-29 }}</ref> The line is wrapped around the spool and can be tightened or reeled in by pulling the tail line. The winch takes the load once the pull is stopped with little operator tension needed to hold it. These also allow controlled release of the tension by the operator using the friction of the line around the ratcheted spool. They are used on small sailing boats and dinghies to control [[Sheet (sailing)|sheets]] and other lines, and in larger applications to supplement and relieve tension on the primary winches.

===Air winch===

An air winch, sometimes known as an air hoist or air tugger, is an air-powered version of a winch. It is commonly used for the lifting and the suspension of materials. In the oil and gas, [[construction]], and maritime industries, air winches are frequently preferred to electric, diesel, and hydraulic winches because of their durability, versatility, and safety.<ref>{{cite web|url=http://www.falckproductions.com/resources/air-winches/what-is-an-air-winch-hoist/|title=What is an Air Winch?|publisher=Falck Productions|access-date=20 June 2012}}</ref><ref>{{cite web|url=http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10764|title=Overhead Hoists, 1926.554|publisher=U.S. DOL, OSHA|access-date=20 June 2012}}</ref>

==See also==
{{col div|colwidth=22em}}
* [[Block and tackle]]
* [[Capstan equation]]
* [[Come-along]]
* [[Harness (disambiguation)]]
* [[Hoist (device)]]
* [[Hoist (mining)]]
* [[Parasailing]]
* [[Portsmouth Block Mills]]
* [[Pulley]]
* [[Steam donkey]]
* [[Wire rope spooling technology]]
{{col div end}}

==References==
{{Reflist}}

==External links==
{{wiktionary}}
{{Commons category}}
*{{cite journal|last=Arctander|first=Erik H.|title=Battery-powered winches|journal=Popular Science|date=May 1995|pages=103–105|url=https://books.google.com/books?id=DwEAAAAAMBAJ&q=Winches&pg=PA103}}

{{Sailing ship elements}}
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[[Category:Mechanisms (engineering)]]
[[Category:Sailing ship components]]
[[Category:Winches| ]]