| Bowline on a Bight | |
|---|---|
 | |
| Category | Loop |
| Related | Double bowline |
| Releasing | Non-jamming |
| Typical use | Forming a loop in the middle of a length of rope. |
| ABoK | #1080 |
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. It is one of the two tie-in knots that are being taught by the German Alpine Club (DAV), generally being considered secure. [1] [2] [3]
2011 testing shows that the knot might slip when only one loop is loaded. Cavers and canyoneers ought to fasten their cow-tail carabiner through both loops. [4] European cavers widely advocate the use of a figure eight twisted version of the bowline on a bight.
This knot can be used to provide a toe hold in the middle of a rope; to make an emergency bosun's chair; [5] [6] and to create an upper rope "block" to make a crude purchase by threading the rope round an anchor point and then back up through the loop. It is sometimes used in sport climbing to tie into two anchor bolts independently. This knot is convenient when a dependable loop is required but neither end of the line is available. It's also commonly used as a seat while being hoisted as there are two secure loops as opposed to the traditional one loop bowline. In theory, this knot would make hoisting many people with one line possible. This knot is very popular in caving as it allows the load to be spread between two anchor points, reducing the stress placed on them and providing a backup should one fail. Commonly known as the Y-hang it allows for a free-hang descent and can be easily adjusted to avoid waterfalls or rub points.
As mentioned earlier, this knot can replace the figure-eight knot when tying into a climbing harness by tying a regular bowline knot and then re-threading it, such as is done with a figure eight knot. However, it is critical to use a strong backup knot with plenty of tail beyond the knot, as the knot may untie during long climbs. The advantage of using this knot instead of the figure eight knot is that it can be easily untied after a severe fall.
The bight of rope is initially used to make a bowline in the usual way (picture on right). However, the bowline is not completed by going on round the standing end(s) and tucking the bight back down beside itself. Instead, the bight is opened up to allow the whole knot to pass through it (see picture on right). When tightened, the bight now embraces the pair of standing ends (see top picture)
Der gesteckte Achterknoten und der doppelte Bulin erfüllen diese Anforderungen. Es sind deshalb auch die beiden Einbindeknoten, die der Deutsche Alpenverein bei seinen Kursen lehrt, wobei der Achterknoten bei Einsteigern den Vorzug erhält, weil er sich leichter kontrollieren lässt.
Der Achterknoten, in diesem Fall als „gesteckter Achter" oder als „doppelter Bulin" ausgeführt, dient als Anseilknoten.
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 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.
The butterfly loop, also known as lineman's loop, butterfly knot, alpine butterfly knot, Swiss loop and lineman's rider, is a knot used to form a fixed loop in the middle of a rope. Tied in the bight, it can be made in a rope without access to either of the ends; this is a distinct advantage when working with long climbing ropes. The butterfly loop is an excellent mid-line rigging knot; it handles multi-directional loading well and has a symmetrical shape that makes it easy to inspect. In a climbing context it is also useful for traverse lines, some anchors, shortening rope slings, and for isolating damaged sections of rope.
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.
The clove hitch is an ancient type of knot, made of two successive single hitches tied around an object. It is most effectively used to secure a middle section of rope to an object it crosses over, such as a line on a fencepost. It can also be used as an ordinary hitch, or as a binding knot, but it is not particularly secure in either application. It is considered one of the most important knots, alongside the bowline and the sheet bend.
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 trucker's hitch is a compound knot commonly used for securing loads on trucks or trailers. The 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.
Figure-eight loop is a type of knot created by a loop on the bight. It is used in climbing and caving.
The Flemish loop or figure-eight loop is perhaps stronger than the loop knot. Neither of these knots is used at sea, as they are hard to untie. In hooking a tackle to any of the loops, if the loop is long enough it is better to arrange the rope as a cat's paw.
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.
A span loop is a non-jamming loop that can be tied away from the ends of the rope.
A climbing harness is a device which allows a climber access to the safety of a rope. It is used in rock and ice climbing, abseiling, and lowering; this is in contrast to other activities requiring ropes for access or safety such as industrial rope work, construction, and rescue and recovery, which use safety harnesses instead.
A Prusik is a friction hitch or knot used to attach a loop of cord around a rope, applied in climbing, canyoneering, mountaineering, caving, rope rescue, ziplining, and by arborists. The term Prusik is a name for both the loops of cord used to tie the hitch and the hitch itself, and the verb is "to prusik". More casually, the term is used for any friction hitch or device that can grab a rope. Due to the pronunciation, the word is often misspelled Prussik, Prussick, or Prussic.
The figure-of-nine loop is a type of knot to form a fixed loop in a rope. Tied in the bight, it is made similarly to a figure-of-eight loop but with an extra half-turn before finishing the knot.
The halter hitch is a type of knot used to connect a rope to an object. As the name implies, an animal's lead rope, attached to its halter, may be tied to a post or hitching rail with this knot. The benefit of the halter hitch is that it can be easily released by pulling on one end of the rope, even if it is under tension. Some sources show the knot being finished with the free end running through the slipped loop to prevent it from working loose or being untied by a clever animal, still allowing easy but not instant untying.
A Yosemite bowline is a loop knot often perceived as having better security than a bowline. 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.
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 trident loop is a fixed loop knot which can jam when heavily loaded. It was proposed as a replacement for the figure-of-eight loop for use in climbing by Robert M. Wolfe, MD, who developed it as a loop form of Ashley's bend. While some tests indicate its strength lies somewhere between the weaker Bowline and stronger figure-of-eight loop, the trident loop shows exceptional resistance to slipping in shock-loading tests.
Karash double loop is a common name for a knot forming two loops. This knot has been a known variant of the Bowline on a bight per the International Guild of Knot Tyers, referred to as bowline twist or twisted collar bowline on a bight. The knot is also referred to as nœud de fusion in French references and sometimes called Fusion knot in English.
A bosun's chair is a device used to suspend a person from a rope to perform work aloft. Originally just a short plank or swath of heavy canvas, many modern bosun's chairs incorporate safety devices similar to those found in rock climbing harnesses such as safety clips and additional lines.
