Sheet bend

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Sheet bend
Schotstek rechts.jpg
NamesSheet bend, becket bend, weaver's knot, weaver's hitch
Category Bend
Efficiency48%–58%
Related Bowline
Typical usejoining two ropes of different diameters
ABoK (simple) #1, #66, #1431; (double) #488, #1434; (weaver's) #2,

The sheet bend (also known as becket bend, weaver's knot and weaver's hitch) is a bend. It is practical for joining lines of different diameter or rigidity.

Contents

It is quick and easy to tie, and is considered so essential it is the first knot given in the Ashley Book of Knots . [1] Additionally, it is one of the six knots given in the International Guild of Knot Tyers' Six Knot Challenge, along with the clove hitch, bowline, reef knot (square knot), round turn and two half-hitches, and sheepshank.

The sheet bend is related in structure to the bowline; like the bowline, it has a tendency to work loose when not under load. For increased security, it is sometimes recommended that one add another turn in the smaller end, making a double sheet bend; in most cases, however, a single sheet bend should suffice.

As a bend, its advantages lie in its simplicity and non-jamming properties.

It is commonly taught in Boy Scouts.

Definition

The term "sheet bend" derives from its use bending ropes to sails (sheets). It is mentioned in David Steel's 1794 book Elements and Practice of Rigging and Seamanship but was used by Neolithic peoples for tying the meshes of fishing nets. [2] The name "weaver's knot" comes from its historic use in textile mills. Even in modern operations, weavers are taught to use this particular knot when correcting broken threads in the warp.

Method

Weaver at Queen Street Mill demonstrating a weaver's knot
Steps in tying a weaver's knot Weavers knot.jpg
Steps in tying a weaver's knot

The sheet bend may be tied by various methods: the basic "rabbit through the hole" method of forming a half hitch in the bight of the larger rope, by a more expedient method shown in Ashley as ABoK #1431 (similar to the method used by an experienced sailor or mountaineer to tie a bowline) or by a trick method (ABoK#2562), involving upsetting a noose knot over a short end of the "larger" rope. Lines of equal size may be joined with a sheet bend, but when one is larger, it plays the simpler role of the "eye" (red line shown in the infobox), rather than the half-hitch (in green)

One type of weaver's knot is topologically equivalent to a sheet bend, but is tied (usually in smaller stuff) with a different approach. Sheet bends are also used for netting.

A fish net made from sheet bends Peche DSC03035.JPG
A fish net made from sheet bends

Notice that, to have any strength, the two free ends should end up on the same side of the knot [3] (see below). Under even moderate load, a left-hand sheet bend will quickly slip and release completely.

Double sheet bend

When lines are of unequal diameter or rigidity it is necessary for security to "double" the sheet bend by making an additional round turn below the first and again bringing the working end back under itself. The free ends should end up on the same side of the knot for maximum strength.

Security

A study of 8 different bends using climbing rope of equal diameter said the sheet bend was weak. In one test, it pulled apart with less than half the pressure that other knots withstood. The authors recommend "2 half hitches on the bend back line and overhand knot on turn thru line." Even with these, it was always a bottom performer and the double sheet bend did little better. However, the butterfly bend did the best. [5]

After performing security testing, Ashley wrote with regard to the Sheet Bend: "Some readers may be surprised to find the Sheet Bend with so low a rating, but these tests were made in exceptionally slippery material. The Sheet Bend is the most practical of bends and quite secure enough for ordinary purposes."

See also

Related Research Articles

Knot Method of fastening or securing linear material

A knot is an intentional complication in cordage which may be practical or decorative, or both. Practical knots are classified by function, including hitches, bends, loop knots, and splices: a hitch fastens a rope to another object; a bend fastens two ends of a rope to each another; a loop knot is any knot creating a loop, and splice denotes any multi-strand knot, including bends and loops. A knot may also refer, in the strictest sense, to a stopper or knob at the end of a rope to keep that end from slipping through a grommet or eye. Knots have excited interest since ancient times for their practical uses, as well as their topological intricacy, studied in the area of mathematics known as knot theory.

Bowline Simple knot used to form a fixed loop at the end of a rope

The bowline is an ancient and simple knot used to form a fixed loop at the end of a rope. It has the virtues of being both easy to tie and untie; most notably, it is easy to untie after being subjected to a load. The bowline is sometimes referred to as King of the knots because of its importance. Along with the sheet bend and the clove hitch, the bowline is often considered one of the most essential knots.

Sheepshank

A shank is a type of knot that is used to shorten a rope or take up slack, such as the sheepshank. The sheepshank knot is not stable. It will fall apart under too much load or too little load.

Clove hitch

The clove hitch is a type of knot. Along with the bowline and the sheet bend, it is often considered one of the most important knots. A clove hitch is two successive half-hitches around an object. It is most effectively used as a crossing knot. It can be used as a binding knot, but is not particularly secure in that role. A clove hitch made around the rope's own standing part is known as either two half-hitches or buntline hitch, depending on whether the turns of the clove hitch progress away from or towards the hitched object.

Although the name clove hitch is given by Falconer in his Dictionary of 1769, the knot is much older, having been tied in ratlines at least as early as the first quarter of the sixteenth century. This is shown in early sculpture and paintings. A round turn is taken with the ratline and then a hitch is added below. The forward end is always the first to be made fast.

The difference between two half hitches and the clove hitch is that the former, after a single turn around a spar, is made fast around its own standing part, while the latter is tied directly around the spar.

Eskimo bowline

The Eskimo bowline is an 'anti-bowline' which is in a class of knots known as 'eye knots'. The eye is formed in the end of the rope to permit attachments/connections. The common bowline is also an 'eye knot'. In the common bowline, the bight component forms around the 'standing part'. In contrast, the bight component of an anti-bowline forms around the ongoing eye-leg.

Marlinespike hitch

The marlinespike hitch is a temporary knot used to attach a rod to a rope in order to form a handle. This allows more tension than could be produced comfortably by gripping the rope with the hands alone. It is useful when tightening knots and for other purposes in ropework.

A whipping knot or whipping is a binding of marline twine or whipcord around the end of a rope to prevent its natural tendency to fray.

Heaving line bend

The heaving line bend is a knot for securely joining two ropes of different diameter or rigidity. It is often used to affix playing strings to the thick silk eyes of an anchorage knot in some stringed instruments. In nautical use, the heaving line bend is used to connect a lighter messenger line to a hawser when mooring ships. It is knot number 1463 in The Ashley Book of Knots, and appeared in the 1916 Swedish knot manual Om Knutar.

Blood knot

A blood knot is a bend knot most usefully employed for joining sections of monofilament nylon line while maintaining a high portion of the line's inherent strength. Other knots used for this purpose can cause a substantial loss of strength. In fly fishing, this serves to build a leader of gradually decreasing diameter with the castable fly line attached at the large diameter end and the fly or hook at the small diameter end. The principal drawback to the blood knot is the dexterity required to tie it. It is also likely to jam, which is not a concern in fishing line, which is no great loss to cut, but may be a concern in normal rope. "Blood knot" may refer to "a double overhand knot tied in a cat-o'-nine-tails."

The barrel knot, called blood knot by Keith Rollo, is the best bend there is for small, stiff or slippery line. The ends may be trimmed short and the knot offers the least resistance possible when drawn through water.

Munter hitch Adjustable knot used control friction in a belay system

The Munter hitch, also known as the Italian hitch or the Crossing Hitch, is a simple adjustable knot, commonly used by climbers, cavers, and rescuers to control friction in a life-lining or belay system. To climbers, this knot is also known as HMS, the abbreviation for the German term Halbmastwurfsicherung, meaning half clove hitch belay. This technique can be used with a special "pear-shaped" HMS locking carabiner, or any locking carabiner wide enough to take two turns of the rope. The Munter hitch is named after Werner Munter, a Swiss mountain guide who popularised its use in mountaineering.

Buntline hitch

The buntline hitch is a knot used for attaching a rope to an object. It is formed by passing the working end around an object, then making a clove hitch around the rope's standing part and taking care that the turns of the clove hitch progress towards the object rather than away from it. Secure and easily tied, the buntline hitch will jam when subjected to extreme loads. Given the knot's propensity to jam, it is often made in slipped form.

The buntline hitch, when bent to a yard, makes a more secure knot than two half hitches, but is more liable to jam. It differs from two half hitches in that the second half hitch is inside instead of outside the first one.

Axle hitch

The axle hitch is used to tie a hitch in a hard-to-reach place, or for extra security by having a double hold on an object. When the initial bight is passed around the object, the rest of the knot can be completed out away from the cramped location. The knot is finished with a bowline knot or other reliable knot that connects the working end to the standing part.

Becket hitch

A becket hitch, including the double becket or figure-of-eight becket hitch, is any hitch that is made on an eye loop, i.e. on a becket. A becket hitch has the same structure as the sheet bend, which joins, or "bends", the ends of two ropes together. The becket hitch, in contrast, fixes a rope to a closed eye or hook. In this instance, a becket means the eye or hook of a pulley block, an eye in the end of a rope, or a rope handle on a sailor's sea chest.

Offset overhand bend

The offset overhand bend is a knot used to join two ropes together. The offset overhand bend is formed by holding two rope ends next to each other and tying an overhand knot in them as if they were a single line. Due to its common use in several fields, this bend has become known by many names, such as thumb knot, openhand knot, one-sided overhand knot or flat overhand bend (FOB), though the terms "one-sided" and "flat" are considered incorrect.

Two half-hitches

Two half-hitches is a type of knot, specifically a binding knot or hitch knot. One variety consists of an overhand knot tied around a post, followed by a half-hitch. This knot is less often referred to as a clove hitch over itself, double half-hitch, or full-hitch.

Two half hitches is the commonest of all hitches for mooring in particular and also for general utility. Steel gives the name in 1794. The difference between two half hitches and the clove hitch is that the former, after a single turn around a spar, is made fast around its own standing part, while the latter is tied directly around the spar.

Bight (knot)

In knot tying, a bight is a curved section or slack part between the two ends of a rope, string, or yarn. A knot that can be tied using only the bight of a rope, without access to the ends, is described as in the bight. The term "bight" is also used in a more specific way when describing Turk's head knots, indicating how many repetitions of braiding are made in the circuit of a given knot.

Harness bend

The harness knot is a general purpose bend knot used to join two ropes together. The knot can be tied under tension and will not capsize.

Swing hitch

Swing hitch is a way to tie a swing rope to a branch or other horizontal beam. Ashley describes it in ABOK as "... firm, strong, secure, and easily untied once the load has been removed."

References

  1. Ashley, Clifford W. (1944). The Ashley Book of Knots. Doubleday. pp. 9, 18.
  2. Shaw, John (2004). The Directory of Knots. Rochester: Grange Books. p. 35.
  3. "Knots and Splicing". ropeinc.com. Single Sheet Bend.
  4. Clifford W. Ashley, The Ashley Book of Knots (New York: Doubleday, 1944), #67 and #1432
  5. Knot Break Strength vs Rope Break Strength