Sheepshank

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Sheepshank

The sheepshank is a type of knot

Knot

A knot is a method for fastening or securing linear material such as rope by tying or interweaving. It may consist of a length of one or more segments of rope, string, webbing, twine, strap, or even chain interwoven such that the line can bind to itself or to some other object?the "load"....
(or, more accurately unknot

Unknot

The unknot arises in the knot theory. Intuitively, the unknot is a closed loop of rope without a knot in it. A knot theorist would describe the unknot as an image of any embedding that can be deformed, i.e....
) that is used to shorten a rope

Rope

A rope is a length of fibers, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength ....
or take up slack.

This knot is obsolete, and when tied with synthetic

Synthetic

Synthetic is usually used in the sense of synthesis, the combination of two or more parts, whether by design or by natural processes. It can also be used as in:...
rope, has been proven to be unsafe. In practice, the sheepshank should never be used, as alternatives are available.

The knot has several features which allow a rope to be shortened:

Other knots will bind tightly and be almost impossible to undo if the knot has been placed under great tension.

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Encyclopedia

The sheepshank is a type of knot

Knot

Unknot

Rope

Synthetic

It provides two loops, one at each end of the knot which can be used to pass another rope through
The knot remains secure under tension; the coarser the rope the more secure it is (see Disadvantages, below)
The knot falls apart easily when tension is removed

Other knots will bind tightly and be almost impossible to undo if the knot has been placed under great tension. The sheepshank, by contrast, comes apart quite easily.

Construction methods

A sheepshank knot may be constructed as follows:

Pull a section of rope back and lay it alongside the rope, so that the rope forms a Z approximately 20 cm long.
Flatten the Z so that there are 3 sections of rope lying alongside each other, with two U-bends where the rope reverses direction.
At each U-bend, grasp the U-bend in one hand, thus holding two of the rope sections. With the other hand form a small loop in the remaining section and draw it over the U-bend so that the loop forms a half hitch and stays there if the free end of the rope is pulled taut.

Many people draw the small loop over facing the wrong way at least half of the time. Instead, make with the U a half-hitch around the other part, by tucking through, then pull the U straight.

Repeat at the other U-bend.

An alternative method for quickly constructing a sheepshank is as follows:

Create a simple loop in the rope, so that the (left) leading end is on top of the (right) trailing end of the loop.
Repeat this process further down the rope to create 3 total loops that overlap slightly (similar to a venn diagram
Venn diagram

Venn diagrams or set diagrams are diagrams that show all hypothetically possible logical relations between a finite collection of Set . Venn diagrams were invented around 1880 by John Venn....
with three circles).
Reach through the outer two loops and grab either side of the middle loop and pull outward while also keeping the rest of the rope slightly taut.
Once the middle loop is pulled through the outer loops, pull on the free ends of the rope to secure.

The result is a flattened loop which is held at each end by a half hitch

Half hitch

The half hitch is a simple knot. If tied by itself, it slips very easily and cannot hold anything. However, it occurs as a component in many more complicated knots....
. If the sides of the flattened loop are pulled away from each other, the flattened loop ends pull out of the half hitches and the knot falls apart, but if the free ends are pulled taut then the knot remains secure.

Usage

Sheepshank knots are typically used for securing loads to trucks or trailers

Trailer (vehicle)

A Trailer is generally an unpowered vehicle Towing by a powered vehicle. Commonly, the term trailer refers to such vehicles used for transport of goods and materials....
, and in sailing

Sailing

Sailing is the art of controlling a boat with large pieces of canvas cloth called sails. By changing the rigging, rudder, and dagger or centre board, a sailor manages the force of the wind on the sails in order to change the direction and speed of a boat....
applications.

Bear Grylls

Bear Grylls

Bear Grylls , real name Edward Michael Bear Grylls, is a British adventurer, television presenter and writer currently best known for his television series Born Survivor ....
uses this knot while rappelling down an edge during the Ireland episode of Man vs. Wild

Man vs. Wild

Born Survivor: Bear Grylls, also called Man vs. Wild or Ultimate Survival , is a survival television series hosted by Bear Grylls, on the Discovery Channel in the United States, Canada, India, Italy, Mexico, New Zealand, Brazil, South Africa, Spain, Australia, Norway, Sweden, Denmark, The Netherlands, Hungary, and Russ...
in order to retrieve his rope at the bottom by severing the middle leg of the sheepshank knot before his descent. He refers to it as a "kamikaze" knot.

Disadvantages

The sheepshank was developed before the use of modern "slippery" synthetic ropes

Synthetic fiber

Synthetic fibers are the result of extensive research by scientists to improve upon naturally occurring animal and plant. In general, synthetic fibers are created by forcing, usually through extrusion, fiber forming materials through holes into the air, forming a thread....
. Constructed from such ropes, under load, it can fail. It is strongly advised that an alternative knot be used.

Variants

Man-o'war sheepshank

The man-o'war sheepshank is a sheepshank knot

Knot

Handcuff knot

A handcuff knot is a knot tied in the bight having two adjustable loops in opposing directions, able to be tightened around hands or feet. The knot itself does not possess any inherent locking action, and thus is not as easy to use for such purposes as the name might suggest....
in the middle. This configuration with the half-hitches formed close to the central knot is used in rope rescue

Rope rescue

Rope rescue is a subset of technical rescue that involves the use of static nylon kernmantle ropes, anchoring and belaying devices, friction abseil devices, various devices to utilize mechanical advantage for hauling systems, and other specialized equipment to reach victims and safely recover them....
and is called a Fireman's chair knot

Fireman's chair knot

A Fireman's chair knot is a knot tied in the bight forming two adjustable, lockable loops. The knot consists of a Handcuff knot finished with a locking half hitch around each loop....
.

Kamikaze knot

External links

Project Gutenberg (September 21, 2004). . Retrieved November 6, 2005. Though the name's a little different, the Sheepshank described above is shown in Figure 79.
Scouting Resources. . Retrieved December 11, 2006. Shows diagrams with accompanying text.