Here is what I believe to be an original binding knot. It seems such an obvious design, in retrospect, that I would not be too surprised to find it previously described. In either case, I'd like to advocate for the use of this binding knot, which is easy to tie, easy to remember, and works well in practice.
NamingI originally thought of calling this the 'Drawstring Knot' for obvious reasons. In writing this description I decided to shorten its name to simply the 'Draw Knot', to emphasizes how smoothly it draws-up.
An alternative name might be the 'Double Bind', since the knot is based on the Clove Hitch, commonly referred to as a Double Hitch.
PurposeI developed this knot with a specific goal in mind. I wanted a binding knot that could be tied in braided nylon rope that was easy to apply, would draw up easily, and have a ratchet like grip.
Ashley described the Constrictor Knot (#1249) as exhibiting these properties. He also described it as "one of the most difficult of knots to untie and is not suitable for rope unless the purpose is a permanent one." Although that was true when working with the high-friction natural fiber ropes of Ashley's day, when I tied the Constrictor Knot in braided nylon the lines slid past each other and the binding came apart.
DescriptionThe Draw Knot has two levels of structure: (1) an embedded clove hitch that nips to seal the knot, and (2) the paired coils (interior sliding lines) that surround the bundle to be bound. The paired sliding lines extend from the clove hitch and loop back around in a circle to pass out though the clove hitch. The tension in the interior sliding lines compresses the clove hitch, tightening its nip.
See figure '1. Loose Basic Form' below.
See figure '2. Tightened Basic Form' below.
Self-Similarity: The clove hitch binds the coils that bind the bundle. The dual 'coils' of the clove hitch run in opposite directions around the sliding lines they tighten about, much like the dual coils of the sliding lines run in opposite directions around the bundle they tighten about.
Several Ways to Tie the Draw KnotTied In the Hand: The Draw Knot is stable when pre-tied and held in the hand. To do so, form a loose clove hitch in the middle of a cord. Lead the two free ends of the clove hitch in opposite directions, circling back to the cove hitch. Pass both free ends out in the same direction through the cove hitch. Then tighten the clove hitch around the two sliding ends. Adjust the circumference of the binding loops so that they can be dropped around the bundle to be bound. Pulling the two free ends in opposite directions closes the binding loop and further tightens the clove hitch about the two free ends.
To open the bind, take hold of both interior sliding lines, up near the clove hitch, and pull them out in opposite directions.
Tied Around a Bundle: The Draw Knot can easily be tied around a bundle. To do so, form a loose clove hitch around the thumb and index finger of your non-dominant hand. Push the loose clove hitch up close to the base of the thumb and index finger so they can open wide. Lead one of the free ends around the bundle and take hold of that end with the thumb and index finger of your non-dominant hand. Run the other free end in the opposite direction around the bundle and again take hold of that line with the thumb and index finger of your non-dominant hand. Pull both running lines out through the clove hitch and work the clove hitch closed around the lines. Then pull the exterior running lines to tighten the bind as desired.
The Draw Knot can also be described as either Two Half Hitches (formed as a clove hitch) or a Buntline Hitch that is 'passed through twice'. You can loosely form either 'cloven' hitch, leaving a long working line and then run that line back around the bundle and rove it out through the clove hitch, in the same direction and parallel with the original 'standing' line. (In a Buntline Hitch the turns of the clove hitch progress towards the held object. With Two Half Hitches the turns of the clove hitch progress away from the object. Since the Draw Knot loops both lines from the clove hitch back around the object and out through the clove hitch, it doesn't matter whether you start with a Buntline or Two Half Hitches; an identical Draw Knot results in either case.)
Tied in the Bight: You should first have a good understanding of the form the knot takes when tied in the hand, because that is the goal you will be working towards. To tie the Draw Knot in the bight, form a clove hitch near the middle of the available line. Push the bights of both lines exiting the hitch back though the clove hitch. (See figure '3. In the Bight' below.) Then carefully turn the clove hitch inside out, adjusting portions to relieve unnecessary twists. Once this is done, arrange the lines directly exiting the clove hitch in opposite directions. The lines from the clove hitch should be formed into a pair of parallel circles running in opposite directions. Both lines exit running out in the same direction through the center of the clove hitch. Tighten the clove hitch and adjust the circumference of the binding loops as desired. Now the binding loops can be dropped around a bundle. Pull the free lines in opposite directions to tighten the bind.
How it WorksPulling the sliding cords to close the bind applies tension to the clove hitch that in turn makes it nip the two sliding cords where they exit. If the tied bundle was completely rigid and static then the force applied to the sliding ends is lead around 360 degrees to compress the clove hitch. However, most bundles will be flexible and spring outwards when compressed and/or consist of elements that dynamically pull apart. Both of these provide additional forces to tension the clove hitch, on an as needed basis.
The clove hitch tends not to jam as it does in a Buntline Hitch because of the two evenly tensioned lines running through it. However, when the binding is pulled very tight around a bundle that flexes, it can be difficult to get hold of the two interior sliding lines to pull them out. If the bind is worked very tight and needs to be opened quickly, cut the free ends up close to the clove hitch and work the outer loop of the clove hitch over the remaining ends. (Or cut into the clove hitch itself.)
Properties- It's stable when pre-tied and held in the hand.
- It can easily be tied around a bundle.
- It can be tied in the bight.
- It closes and tightens when both free ends are pulled in opposite directions.
- It does not close further when both free ends are pulled together in the same direction. You can lift a tied bundle by holding the two free ends together in hand. This aspect of its stability makes it easy to work with.
- The sliding lines move with least resistance when they slide together in the same direction. This contributes to closing (and opening) the binding evenly on both sides.
- It can bind a bundle as narrow as the cords used to tie the knot.
- It can be used across an open space, for pulling two objects together.
- It is very stable as long as a constant tension is applied to pull the loop apart (from the inside). However, it can loosen if the tension is repeatedly released and reapplied, since the clove hitch will not maintain its nip when the applied tension is eased. There are many ways to cease the knot. A fast way to cease the bind is to tie the two free ends into a Flat Overhand Bend, up close to the clove hitch.
- As a 'trick knot' ("To tie up a Houdini" ABoK #2560) it looks like a normal binding knot, so a person unfamiliar the Draw Knot is likely to attempt to loosen the central clove hitch, which is has no loose ends.
- A drawback to the Draw Knot is that one can mistakenly pull the running ends back in the wrong direction, making a U-turn around the clove hitch instead of passing straight through it to the other side. (See figure '4. U-Turn' below.) In this case the coils of the bind still close when the two free ends are pulled in opposite directions, but the sliding lines also tend to pull the clove hitch open from within, even while increasing the tension at either end of the clove hitch that would normally close it.
ApplicationI have tied the Draw Knot in braided nylon rope of different diameters for temporary binds. I've also tied the Draw Knot in waxed dental floss to provide a low profile, semi-permanent binding. It served reliably in all cases.
DerivationThe Draw Knot is probably closer to a Double Ring Knot (ABoK #1126, also called the Double Running Knot) than anything else. If you replace the Ring Hitch with a Clove Hitch and run the free lines around in their 'preferred' direction before passing them out through the clove hitch, the Draw Knot is formed.
Of course I tried many other closing loops including the Constrictor but it tends to loose its shape when surrounding something as narrow as a pair of cords. The Double Overhand Knot faired better, but it relied on the friction in the knot, rather than seizing down as tension was applied to its ends.
Compared to the Constrictor KnotThe Constrictor Knot is simpler, and more streamlined than the Draw Knot. The clove hitch at the closing of the Draw Knot makes it 'knobby'. The Draw Knot is designed to hold better in braided nylon and other slippery synthetic fibers. The ends of a Constrictor Knot leave in parallel with the binding coils, while ends of a Draw Knot leave at right angles to the binding coils. I find it easier to remember how to tie the Draw Knot than the Constrictor, when used infrequently.
Compared to the Gleipnir Knot
See:
http://igkt.net/sm/index.php?topic=1449.0The single loop Gleipnir Knot is a very elegant and effective binding. Like the Draw Knot, the Gleipnir has its closing twisted loop (or half hitch) in the middle of the paired coils. Tension applied to by pulling the sliding lines apart is transmitted back around the coils to tighten the closing loop that nips the sliding lines to seal the bind.
The single loop Gleipnir is less stable than the Draw Knot under certain conditions: If the lines are unevenly loaded, such that the adjustable side sees even a little more load, the binding slips. Differential tension is applied to the lines to release the knot. If the free ends are not secured a tug on one of them may unseat the closing loop.
The clove hitch of the Draw Knot has more stability than a single loop. Thus it is tempting to compare the Draw Knot to a double loop Gleipnir, with its loops arranged in a half hitch. It appears to me that the clove hitch nips the sliding lines tighter when they run through at right angles to the outer lines of its hitches, then when the sliding lines run parallel to the outer lines of the clove hitch. (I don't have either the theory or instrumentation at hand to prove this; it simply feels that way when I pull.)
Like the Gleipnir Knot:
(1) The Draw Knot can be used across a flat surface or in the open air such as when two pipes are separated and the closing loop tied in the middle. It can be used for lifting or for pulling two objects together.
(2) The Draw Knot binding can work loose when subjected to "intermittent slack and tightening such as a shifting load or something blowing in the wind."