Joining two ends of a single line to bind around an object.
Caveat
Not secure as a bend unless secured by additional knots(ex: overhand). Spills easily if one of the free ends is pulled outward. Does not hold well if the two lines are not the same thickness.
The reef knot, or square knot, is an ancient and simple binding knot used to secure a rope or line around an object. It is sometimes also referred to as a Hercules knot or Heracles knot. The knot is formed by tying a left-handed overhand knot between two ends, instead of around one end, and then a right-handed overhand knot via the same procedure, or vice versa. A common mnemonic for this procedure is "right over left; left over right", which is often appended with the rhyming suffix "... makes a knot both tidy and tight". Two consecutive overhands tied as described above of the same handedness will make a granny knot. The working ends of the reef knot must emerge both at the top or both at the bottom, otherwise a thief knot results.
The reef knot or square knot consists of two half knots, one left and one right, one being tied on top of the other, and either being tied first...The reef knot is unique in that it may be tied and tightened with both ends. It is universally used for parcels, rolls and bundles. At sea it is always employed in reefing and furling sails and stopping clothes for drying. But under no circumstances should it ever be tied as a bend, for if tied with two ends of unequal size, or if one end is stiffer or smoother than the other, the knot is almost bound to spill. Except for its true purpose of binding it is a knot to be shunned.
The reef knot is not recommended for tying two ropes together, because of the potential instability of the knot when not stabilized; something that has resulted in many deaths (see Misuse as a bend).
Naming
The reef knot is at least 4,000 years old. The name "reef knot" dates from at least 1794[2] and originates from its common use to reef sails,[3][4] that is to tie part of the sail down to decrease its effective surface area in strong winds. To release the knot a sailor could collapse it with a pull of one hand; the sail's weight would make the collapsed knot come apart. It is specifically this behavior which makes the knot unsafe for connecting two ropes together.[5]
The name "square knot" is found in Dana's 1841 maritime compendium A Seaman's Friend, which also gives "reef knot" as an alternative name.[6][7]
The name square knot is often used for the unslipped version of reef knot. Reef knot itself then is understood as the single slipped version, while the name shoelace knot is to indicate double slipped version. Sometimes the name bowtie also may be used to indicate a double slipped version, but tying a bowtie is usually performed on flat material, and involves a slip knot of one end holding a bight of the other end i.e. not really a double slipped reef knot. The name "Square knot" is also used for completely different other knots such as the mathematical concept of square knot, or friendship knot; this last one earns the name by being flat and drawing a square on one face (and a cross on the other face).
Uses
The reef knot is used to tie the two ends of a single rope together such that they will secure something, for example a bundle of objects, that is unlikely to move much. In addition to being used by sailors for reefing and furling sails, it is also one of the key knots of macrame textiles.[8]
The knot lies flat when made with cloth and has been used for tying bandages for millennia. As a binding knot it was known to the ancient Greeks as the Hercules knot (Herakleotikon hamma) and is still used extensively in medicine.[9] In his Natural History, Pliny relates the belief that wounds heal more quickly when bound with a Hercules knot.[10]
It has also been used since ancient times to tie belts and sashes. A modern use in this manner includes tying the obi (or belt) of a martial artskeikogi.
With both ends tucked (slipped) it becomes a good way to tie shoelaces, whilst the non-slipped version is useful for shoelaces that are excessively short. It is appropriate for tying plastic garbage or trash bags, as the knot forms a handle when tied in two twisted edges of the bag.
A surgeon's variation, used where a third hand is unavailable, is made with two or three twists of the ropes on bottom, and sometimes on top, instead of just one.
Detail of Egyptian statue dating from 2350 BC depicting a reef knot securing a belt
Ancient Greek jewelry from Pontika (Ukraine), 300 BC, in the form of a reef knot
Singly slipped reef knot
Diagram of common shoelace bow knot, a doubly slipped reef knot
The reef knot can capsize (spill) when one of the free ends is pulled outward.
The reef knot's familiarity, ease of tying, and visually appealing symmetry conceal its weakness. The International Guild of Knot Tyers warns that this knot should never be used to bend two ropes together.[14] However, modern instruction teaches that it is fine for noncritical applications,[15] especially if stabilized. A proper bend knot, for instance a sheet bend or double fisherman's knot, should be used instead. Knotting authority Clifford Ashley claimed that failures of misused reef knots have caused more deaths and injuries than failures of all other knots combined.[16] Further, it is easily confused with the granny knot, which is a very poor knot.
Physical analysis
An approximate physical analysis[17] predicts that a reef knot will hold if , where μ is the relevant coefficient of friction. This inequality holds if . Experiments show that the critical value of μ is actually somewhat lower.[18]
↑ Hage, J. Joris (April 2008), "Heraklas on Knots: Sixteen Surgical Nooses and Knots from the First Century A.D.", World Journal of Surgery, vol.32, no.4, pp.648–655, doi:10.1007/s00268-007-9359-x, PMID18224483, S2CID21340612
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.
The overhand knot is one of the most fundamental knots, and it forms the basis of many others, including the simple noose, overhand loop, angler's loop, reef knot, fisherman's knot, half hitch, and water knot. The overhand knot is a stopper, especially when used alone, and hence it is very secure, to the point of jamming badly. It should be used if the knot is intended to be permanent. It is often used to prevent the end of a rope from unraveling. An overhand knot becomes a trefoil knot, a true knot in the mathematical sense, by joining the ends. It can also be adjusted, faired, or mis-tied as a half hitch.
The granny knot is a binding knot, used to secure a rope or line around an object. It is considered inferior to the reef knot, which it superficially resembles. Neither of these knots should be used as a bend knot for attaching two ropes together.
The granny knot is also called the false, lubber's, calf, and booby knot. Patterson's Nautical Encyclopedia calls it "old granny knot" and Sir Edwin Arnold calls it the "common or garden knot." The name granny is given in Vocabulary of Sea Phrases and Roding pictures the knot in 1795.
The granny consists of two identical half knots, one tied on top of the other. It has but one practical purpose that I know of and that is to serve as a surgeon's knot. Formerly it was employed for tying up parcels in five-and-ten-cent stores, but the practice was given up and paper bags substituted as they were found to be simpler.
The constrictor knot is one of the most effective binding knots. Simple and secure, it is a harsh knot that can be difficult or impossible to untie once tightened. It is made similarly to a clove hitch but with one end passed under the other, forming an overhand knot under a riding turn. The double constrictor knot is an even more robust variation that features two riding turns.
The thief knot resembles the reef knot except that the free, or bitter ends are on opposite sides. It is said that sailors would secure their belongings in a ditty bag using the thief knot, often with the ends hidden. If another sailor went through the bag, the odds were high the thief would tie the bag back using the more common reef knot, revealing the tampering, hence the name. It is difficult to tie by mistake, unlike the granny knot, unless one attempts to tie a square knot in a similar manner to a sheet bend, then it is possible to tie accidentally.
The figure-eight knot or figure-of-eight knot is a type of stopper knot. It is very important in both sailing and rock climbing as a method of stopping ropes from running out of retaining devices. Like the overhand knot, which will jam under strain, often requiring the rope to be cut, the figure-eight will also jam, but is usually more easily undone than the overhand knot.
The figure-eight or figure-of-eight knot is also called the Flemish knot. The name figure-of-eight knot appears in Lever's Sheet Anchor; or, a Key to Rigging. The word "of" is nowadays usually omitted. The knot is the sailor's common single-strand stopper knot and is tied in the ends of tackle falls and running rigging, unless the latter is fitted with monkey's tails. It is used about ship wherever a temporary stopper knot is required. The figure-eight is much easier to untie than the overhand, it does not have the same tendency to jam and so injure the fiber, and is larger, stronger, and equally secure.
A bend is a type of knot used to join two lengths of rope. Bends are used in a variety of situations, including climbing, sailing, and securing loads. They are classified based on their ability to be tightened or released, their resistance to slipping, and their strength. Some common types include the sheet bend, the double fisherman's knot, and the double figure-eight bend. Bends allow two ropes to be securely joined together, enabling the combined ropes to support weight or transmit force. It is important to choose the appropriate bend for the specific task at hand, as some may be stronger or more secure than others.
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.
A grief knot is a knot which combines the features of a granny knot and a thief knot, producing a result which is not generally useful for working purposes. The word grief does not carry its usual meaning but is a portmanteau of granny and thief.
Shoelaces, also called shoestrings or bootlaces, are a system commonly used to secure shoes, boots, and other footwear. They typically consist of a pair of strings or cords, one for each shoe, finished off at both ends with stiff sections, known as aglets. Each shoelace typically passes through a series of holes, eyelets, loops or hooks on either side of the shoe. Loosening the lacing allows the shoe to open wide enough for the foot to be inserted or removed. Tightening the lacing and tying off the ends secures the foot firmly within the shoe. The laces can be tied in different shapes, most commonly a simple bow.
The sheet bend is a bend knot. It is practical for joining lines of different diameter or rigidity.
A stopper knot is a knot that creates a fixed thicker point on an otherwise-uniform thickness rope for the purpose of preventing the rope, at that point, from slipping through a narrow passage, such as a hole in a block. To pass a rope through a block, or hole, is to reeve it. To pull it out is to unreeve it. Stopper knots prevent the rope from unreeving on its own.
The surgeon's knot is a surgical knot and is a simple modification to the reef knot. It adds an extra twist when tying the first throw, forming a double overhand knot. The additional turn provides more friction and can reduce loosening while the second half of the knot is tied. This knot is commonly used by surgeons in situations where it is important to maintain tension on a suture, giving it its name.
The offset overhand bend is a knot used to join two ropes together end-to-end. It 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.
Ashley's bend is a knot used to securely join the ends of two ropes together. It is similar to several related bend knots which consist of two interlocking overhand knots, and in particular the alpine butterfly bend. These related bends differ by the way the two constituent overhand knots are interlocked.
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.
The shoelace knot, or bow knot, is commonly used for tying shoelaces and bow ties.
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