Bowline

Last updated
Simple Bowline
Palstek innen.jpg
NamesSimple Bowline, boling knot (archaic)
Category Loop
Origin Ancient
Related Sheet bend, double bowline, water bowline, Yosemite bowline, Spanish bowline, Portuguese bowline, triple bowline, bowline on a bight, running bowline, poldo tackle, Eskimo bowline, cowboy bowline, Cossack knot, Kalmyk loop
Releasing Jamming
Typical useMaking a fixed loop in the end of a line
CaveatWhile widely considered a reliable knot, when tied in certain materials or loading conditions it may not hold. Tends to work itself loose when not under tension.
ABoK #1010, #1716
Instructions

The #1010 Simple Bowline ( /ˈblɪn/ or /ˈbln/ ) [1] is an ancient and simple knot used to form a fixed eye (aka loop) at the end of a line. It has the virtues of being both easy to tie and untie; most notably, it is easy to untie after being subjected to a heavy load. The Simple Bowline is sometimes referred to as King of the knots because of its resistance to jamming and simple, easy to remember structure. Along with the sheet bend and the clove hitch, the simple Bowline is often considered one of the most essential knots. [2]

Contents

There is an important but often unreported relationship between end-to-end joining knots (ie 'bends') and fixed eye knots. All 'bends' have 4 corresponding eye knots (within a chiral orientation). The #1431 Sheet bend and simple Bowline are closely related. For example: The Sheet bend has 4 corresponding eye knots - one of which is none other than the #1010 Simple Bowline. Harry Asher was likely the first to publish the relationship between a 'bend' and its corresponding fixed eye knot(s).

In applications where there is a constant load, the simple Bowline is generally considered reliable. However, it is vulnerable to changing (cyclic) loads and slack shaking and under such conditions has a tendency to work loose. The structure is also vulnerable to a transverse loading profile (some use the term 'ring loading'). [3] [4] If the type of loading profile is known and understood to be in a transverse direction, a variation where the tail is outside of the eye will be more suitable (refer illustration 1034 1/2 in Ashley Book of Knots). One of corresponding eye knots of the #1431 Sheet bend is known as the 'Boas' Bowline (also known as Cossack or Kalmyk Bowline) - and it is also resistant to a transverse loading profile.


History

The bowline's name has an earlier meaning, dating to the age of sail. On a square-rigged ship, a bowline (sometimes spelled as two words, bow line) is a rope that holds the edge of a square sail towards the bow of the ship and into the wind, preventing it from being taken aback. [5] A ship is said to be on a "taut bowline" when these lines are made as taut as possible in order to sail close-hauled to the wind. [6]

The bowline knot is thought to have been first mentioned in John Smith's 1627 work A Sea Grammar under the name Boling knot. Smith considered the knot to be strong and secure, saying, "The Boling knot is also so firmly made and fastened by the bridles into the cringles of the sails, they will break, or the sail split before it will slip." [7] [lower-alpha 1]

Another possible finding was discovered on the rigging of the Ancient Egyptian Pharaoh Khufu's solar ship during an excavation in 1954. [8]

Structure

All Bowlines have the following key components:

If any of these key components are missing, the knot structure isn't deserving of the title 'Bowline'.

Usage

The bowline is used to make a loop at one end of a line. It is tied with the rope's working end also known as the "tail" or "end". The loop may pass around or through an object during the making of the knot. The knot tightens when loaded at (pulled by) the standing part of the line.

The simple Bowline is commonly used in sailing small craft, for example to fasten a halyard to the head of a sail or to tie a jib sheet to a clew of a jib. The bowline is well known as a rescue knot for such purposes as rescuing people who might have fallen down a hole, or off a cliff onto a ledge. This knot is particularly useful in such a situation because it is possible to tie with one hand. As such, a person needing rescue could hold onto the rope with one hand and use the other to tie the knot around their waist before being pulled to safety by rescuers. The Federal Aviation Administration recommends the bowline knot for tying down light aircraft. [9]

A rope with a bowline retains approximately 2/3 of its strength, with variances depending upon the nature of the rope, as in practice the exact strength depends on a variety of factors.

In the United Kingdom, the knot is listed as part of the training objectives for the Qualified Firefighter Assessment. [10]

Tying

A mnemonic used to teach the tying of the bowline is to imagine the end of the rope as a rabbit, and where the knot will begin on the standing part, a tree trunk. First a loop is made near the end of the rope, which will act as the rabbit's hole. Then the "rabbit" comes up the hole, goes round the tree right to left, then back down the hole. This can be taught to children with the rhyme: "Up through the rabbit hole, round the big tree; down through the rabbit hole and off goes he." A single handed method can also be used; see this animation.

There is a potential with beginners to wrongly tie the bowline. This faulty knot stems from an incorrect first step while tying the rabbit hole. If the loop is made backwards so that the end of the rope (the bitter end) is on the bottom, the resulting knot will be sideways. The final loop of a sideways bowline will slip[ citation needed ]. This makes it particularly dangerous[ citation needed ] in the case of an inexperienced sailor, who, in addition to having an insecure knot, is also less familiar with what to do should it come untied on the water.

If a bowline is tied and the two free ends of the rope are brought together in the simplest way, the mathematical knot obtained is the so-called 6₂ knot. The sequence of necessary moves are depicted here:

Security

The Simple (#1010) Bowline is not suitable for employment in life critical applications (eg rock climbing, abseiling, canyoning, etc). The Simple Bowline is vulnerable to cyclic loading and/or slack shaking loading profiles and will begin to loosen and unravel. Mountaineers and rock climbers have long understood this and have devised a number of variations to overcome these vulnerabilities. The techniques to convert the #1010 Simple Bowline into an inherently secure form usually involve additional tail maneuvers (which can add varying degrees of complexity). Inherently secure Bowlines do not require any additional backup 'stopper knot'. Examples of inherently secure Bowlines include; Lees link Bowline, EBSB Bowline, Scotts locked Bowline, and Harry Buttlers Bowline. An excellent learning resource for people who are vertical rope rescue operators or rope access technicians is found at this link: http://www.paci.com.au/knots.php The simple (#1010) Bowline is known to be vulnerable to transverse loading profile (sometimes referred to as 'ring' loading). Ashley shows a tail outside version of the simple Bowline at illustration #1034 1/2. This version (with the tail outside of the eye) is more resistant to a transverse loading profile.

Strength

The most important factors with all knots include; stability, security, resistance to jamming, TIB (whether the knot is Tiable In the Bight), amount of rope required to form the knot, and footprint (ie volume/bulk). Strength is largely irrelevant. In fact, many knot book authors and commentators appear to be fixated on MBS yield (ie strength) - and seem to have no other way of conceptualizing a knot. Indeed, the notional concept of knot 'efficiency' is typically associated with MBS yield (ie strength) - which is manifestly wrong. The metrics of knot 'efficiency' really ought to be conceptualized in terms of the aforementioned factors.


Other variants include:

Round turn bowline

The round turn Bowline (ie Double Bowline) is made by the addition of an extra turn in the formation of the "rabbit hole" before the working end is threaded through. It is shown at illustration #1013 in Ashley Book of Knots.

Water bowline

Similar to the double bowline, the water bowline is made by forming a clove hitch before the working end is threaded through. This variation does not boost security and does not alter the MBS yield of the knot. Perhaps in ancient times before the introduction of modern synthetic ropes, the additional nipping loop may have had some benefit (ie in vegetable fibre ropes).

Yosemite bowline

In this variation the knot's working end is taken round the loop in the direction of the original round turn, then threaded back up through the original round turn before the knot is drawn tight. The Yosemite bowline is often used in climbing. However, the so-called 'Yosemite finish' requires the rope to perform a tight U turn around the outgoing eye leg of the Bowline. Caution is required when using stiffer ropes - as this tail maneuver and exit through the collar may not be so secure. Care must also be taken when forming the core of the knot - if the tail is yanked before the nipping loop has been cinched, the tail will become displaced - resulting in an unstable structure.

Other variants

Two-loop Birmingham bowline before tightening and dressing the knot. Two turns taken around the standing part of the line form two loops. Birmingham Bowline Loose.jpg
Two-loop Birmingham bowline before tightening and dressing the knot. Two turns taken around the standing part of the line form two loops.

The cowboy bowline (also called Dutch bowline), French bowline, and Portuguese bowline are variations of the bowline, each of which makes one loop. (Names of knots are mostly traditional and may not reflect their origins.) A running bowline can be used to make a noose which draws tighter as tension is placed on the standing part of the rope. The Birmingham bowline has two loops; the working part is passed twice around the standing part (the "rabbit" makes two trips out of the hole and around the tree). Other two-loop bowline knots include the Spanish bowline and the bowline on the bight; these can be tied in the middle of a rope without access to the ends. A triple bowline is used to make three loops. [11] A Cossack knot is a bowline where the running end goes around the loop-start rather than the main part and has a more symmetric triangular shaped knot. A slipped version of the Cossack knot is called Kalmyk loop. [12] [13]

See also

Notes

  1. The orthography of this quote has been modernized for clarity.

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.

Sheepshank Type of knot

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.

Truckers hitch

The trucker's hitch is a compound knot commonly used for securing loads on trucks or trailers. This general arrangement, using loops and turns in the rope itself to form a crude block and tackle, has long been used to tension lines and is known by multiple names. Knot author Geoffrey Budworth claims the knot can be traced back to the days when carters and hawkers used horse-drawn conveyances to move their wares from place to place.

Eskimo bowline

The Eskimo bowline, reverse bowline, or 'anti-bowline' 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.

Zeppelin bend

A Zeppelin bend is an end-to-end joining knot formed by two symmetrically interlinked overhand knots. It is stable, secure, and highly resistant to jamming. It is also resistant to the effects of slack shaking and cyclic loading.

Double bowline

A double bowline is a type of loop knot. Instead of the single turn of the regular bowline, the double bowline uses a round turn. This forms a more secure loop than a standard bowline.

Climbing harness

A climbing harness is an item of climbing equipment for rock-climbing, abseiling, or other activities requiring the use of ropes to provide access or safety such as industrial rope access, working at heights, etc. A harness secures a person to a rope or an anchor point.

Sheet bend

The sheet bend is a bend. It is practical for joining lines of different diameter or rigidity.

Triple bowline

The triple bowline knot is a variation of the bowline knot. The knot can be applied to emergency situations, such as mountain rescue.

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.

Cowboy bowline

The cowboy bowline is a variation of the bowline loop knot.

Bowline on a bight Knot that makes a pair of fixed-size loops in the middle of a rope

The Bowline on a bight is a knot which makes a pair of fixed-size loops in the middle of a rope. Its advantage is that it is reasonably easy to untie after being exposed to load. This knot can replace the figure-eight loop knot when tying into a climbing harness. It is one of the two tie-in knots that are being taught by the German Alpine Club (DAV), generally being considered secure.

Yosemite bowline Loop knot often perceived as having better security than a bowline

A Yosemite bowline is a loop knot often perceived as having better security than a bowline. It has been pointed out that if the knot is not dressed correctly, it can potentially collapse into a noose, however testing reveals this alternative configuration to be strong and safe as a climbing tie-in.

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.

Carrick bend loop

A carrick bend loop or carrick loop is a knot used to make a reliable and stable loop at the end of a rope formed by the tail turned around and attached to the main part using a carrick bend.

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. Random House Dictionary
  2. Cassidy 1985, The Klutz Book of Knots
  3. "How safe is the bowline knot in different situations?". The Great Outdoors. Retrieved 12 March 2013.
  4. "LOOP KNOTS". www.helsinki.fi. Retrieved 2017-06-01.
  5. Ashley, Clifford W (1944). The Ashley Book of Knots. Doubleday. p. 186.
  6. Kemp's Yachting Dictionary
  7. "The Seaman's Grammar and Dictionary (reprinting)" (PDF). Randal and Taylor. 1691. p. 25.
  8. Love, Kennett (1954-12-12), "Vessel of Cheops Appears Intact On Close Inspection From Above", New York Times, sec. 1, pp. 1,3, ...as well as a curiously intricate knot on a piece of rigging that appeared to be basically akin to a bowline knot.
  9. "Tiedown Sense". Advisory Circular (AC) 20-35C. Federal Aviation Administration. 7 December 1983. pp. 11–12. Archived from the original on 28 December 2005. Retrieved 7 May 2004.
  10. Defence Fire Training and Development Centre. "Qualified Firefighter Assessment – Part 2 Training Objectives" (PDF). Archived from the original (PDF) on 2016-03-11.
  11. https://www.youtube.com/watch?v=4yL4izuwaxg 10 different bowlines quick in less than 3 min, slow repeat thereafter
  12. Video on YouTube Tying video for Kalmyk loop
  13. Video on YouTube Tying video for Kalmyk loop