Double-Loop Knots
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If you have never visited this website before then I would recommend that you begin at the Home Page. It explains that the type of rope you use, the age of the rope, the wear and tear on the rope, the types of knots you tie, whether you tied the knots properly or not, whether you "dressed" the knots properly or not, whether you "set" the knots properly or not, and so on, all have an impact on the Safe Working Load of your rope and the security of the knots you tie. Whatever risks are associated with the rope or string that you use and the knots that you tie, remember that the risks are entirely your own.
Here is a list of the articles in this series. Every link will open up in a new window to give you more control as you browse around in this website:
Two loops are often more secure than a single loop (because they provide a double hold on an object), especially when hoisting or lowering an injured person or a large or heavy object. When lifting or lowering a person, a double-loop knot can be used as a sling.
If you don't tie knots in rope very often then it might be difficult to remember which knot to use, and how to tie it properly, when you need a double-loop knot. Therefore, it's a good idea to learn one strong knot which you can remember easily. My preference is the Double Alpine Butterfly, for reasons which I'll describe throughout this article.
Be sure to practice tying your favorite knots periodically (from different angles) so that you'll know how to tie them when you need them.
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In The Complete Rigger's Apprentice (p.59), Brion Toss says that "This knot (Figure 3-17) is a little tricky to tie, but its splayed loops make it preferable to the Bowline on the Bight for some slinging applications (ladders, pallets) and for sitting in. Either knot is good as an emergency bosun's chair."
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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If you are familiar with the basic Bowline then the Birmingham Bowline is easy to remember how to tie, it is fairly easy to tie, it is fairly easy to dress, and it is easy to untie after it has held a load. Also, it is versatile because it can either be tied before the loops are put to use, or else you can pass the end of the rope around an object as you create the knot. One disadvantage of this knot is that it can't be tied in the middle of a rope (when you don't have access to the ends of the rope).
I haven't been able to find any strength ratings for this knot, but if you absolutely need to pass the rope around an object while tying a double-loop knot then this might be a knot to consider.
However, for the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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If you know how to tie the basic Bowline then the Bowline on the Bight is fairly easy to remember once you get the hang of it. It is easy to tie and easy to dress, it is easy to untie after it has held a load, and the two loops can be re-sized fairly easily. It is generally considered to have the same strength rating as the basic Bowline.
Ashley says that "It is the knot generally used at sea for lowering an injured man from aloft." (The Ashley Book of Knots, p.194, #1080). As Ashley points out, this knot has a long track record of use in rescue situations, so it is considered by many sailors and rescue workers to be a strong enough knot to be used when lives are at stake. One potential disadvantage of the Bowline on the Bight is that you can't pass the end of the rope around an object while tying the knot, but this might not be something that you would need to do very often. Ashley also points out that the pull on the two ends should be approximately parallel, which is a potential disadvantage that the Double Alpine Butterfly does not have.
According to Budworth, "all sailors sooner or later are faced with some urgent improvisation. This is one such knot, which can be used for lowering an injured person and other emergencies. One leg is put through each loop and the patient (if conscious and capable) holds tight onto the rope at chest level, or is somehow secured to it. It reduces the strength of the line in which it is tied by up to 40%." (The Complete Book of Knots, p.38).
In The Complete Rigger's Apprentice, Brion Toss says that the Bowline on a Bight "is not entirely dependable when the strain comes on one part only or when the two standing parts are pulled in opposite directions. In the former instance, make a Bowline on a Bight with a Bowline on it [i.e. tie off the end of the rope with a Bowline, somewhere above the knot formed by the Bowline on a Bight] (Figure 3-14B). In the latter instance try a different knot such as the Farmer's Loop (Figure 3-15) or the Butterfly Knot (Figure 3-16)." (p.58, brackets added).
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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The Double Alpine Butterfly seems to have all of the advantages and disadvantages of the Alpine Butterfly, except that it can't easily be made in such a way that you are able to pass the two main loops around an object while you are tying the knot. However, this might not be something that you would need to do very often.
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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The basic single-loop Double Dragon (picture 8 above) can easily be converted into a double-loop Double Dragon simply by loosening the knot and then pushing the tip of the main loop through the loosened knot until it looks like picture 3 above. Then follow the remaining pictures (above) to complete the Double Double Dragon.
Method #2
Here is an alternate way to tie the Double Double Dragon which allows you to create two or more loops around an object
while
you tie the knot (rather than
after
you tie the knot as with the method above). Begin by tying the first few steps of the
single-loop Double Dragon
until you reach a configuration similar to picture 1 (below). You now have a
bight
of rope laying across your fingers with a strand of rope coming through it. Pass the end of the rope into the
bight,
then over the top and around the
bight,
then back out of the
bight
again as in picture 2. Notice in picture 2 that you have tied a
Reef Knot.
Now you simply finish tying a
single-loop Double Dragon
in the normal way by passing the end of the rope around the object (creating a second loop around the object), then passing the end of the rope into the
bight
and around your fingers until it lays over the tops of the two strands of rope on your fingers (picture 3). Wrap the end of the rope twice around the two strands of rope on top of your fingers and then tighten the knot, just like you would do with the
single-loop Double Dragon
(picture 4). In picture 4, pull out the strand of rope which you created in picture 2, and use it to adjust the relative sizes of the two loops which have been passed around the object, then finish dressing and setting the knot (picture 5).
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To make three or more loops, tie the knot until you finish picture 2, then pass the end of the rope around the object (to make the second loop around the object). Now follow picture 2 again to pass the end of the rope into the bight, then over the top and around the bight, then back out of the bight again, then pass the end of the rope around the object for the third time, and so on. To see a picture of the finished triple-loop knot, see the Triple Double Dragon.
The Double Double Dragon seems to have all of the advantages and disadvantages of the single-loop Double Dragon.
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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The Double Figure-Eight Loop seems to have all of the advantages and disadvantages of the Figure-Eight Loop, except that it can't easily be made in such a way that you are able to pass the two main loops around an object while you are tying the knot. However, this might not be something that you would need to do very often.
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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The French Bowline is slightly easier to tie than the Birmingham Bowline, and it seems to have basically the same advantages and disadvantages as the Birmingham Bowline. One disadvantage with the French Bowline is that it is fairly easy for one of the loops to get bigger and the other loop to get smaller. This can potentially pose a hazard when hoisting or lowering people or heavy objects because it might allow the load to shift.
The French Bowline is also called the Portuguese Bowline in some books and websites, but I have seen other websites (such as this one) which describe the Portuguese Bowline slightly differently. Rather than bringing the end of the rope through the small loop in picture 1, you bring the end of the rope on top of the small loop. According to some people, this is the difference between the French and Portuguese Bowlines. I haven't been able to find any strength ratings for the French or Portuguese Bowlines, but they would appear to have a similar strength rating as the basic Bowline because the core knot configuration is the same.
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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One advantage is that the Spanish Bowline can be tied in the middle of a rope when you don't have access to the ends of the rope (unlike the Birmingham Bowline and the French/Portuguese Bowlines). However, it might be possible for the loops to change sizes (posing the same hazard as the French/Portuguese Bowlines), and it can be difficult to remember how to tie this knot when you need it. Somewhere I saw that this knot is not rated very highly, but I have not been able to find that reference. Other than that, I haven't seen any strength ratings for the Spanish Bowline.
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
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One advantage with the Triple Crown is that it can be tied in the middle of a rope when you don't have access to the ends of the rope (unlike the Birmingham Bowline and the French/Portuguese Bowlines). Additionally, the loops can't easily grow or shrink accidentally, so this knot is safer in that respect than the French/Portuguese Bowlines or the Spanish Bowline. However, it might be difficult to remember how to tie this knot when you need it.
I have not been able to find any strength ratings for the Triple Crown.
For the average person who only wants to learn one strong double-loop knot, my choice would be the Double Alpine Butterfly.
I haven't seen anything written about the strength and security of the Birmingham Bowline or the French (Portuguese) Bowline, but they have an advantage in that the rope can easily be passed around an object while tying the knot. They have another potential advantage in that you can easily create any number of loops with these knots. One disadvantage is that these knots cannot be tied in the middle of a rope (when you don't have access to the ends of the rope). Another potential disadvantage with the French/Portuguese Bowline is that some of the loops might accidentally change size, which can allow the load to shift dangerously.
With the Spanish Bowline, the rope can pass fairly easily between the two loops. This can be hazardous if it allows a heavy load to shift while being hoisted, lowered, or towed. In addition, the Spanish Bowline can be difficult to remember how to tie if you don't use it very often.
The Triple Crown is an attractive knot with splayed loops (in other words, the two loops don't lay on top of each other). However, not much is written about this knot and so I can't tell what kind of track record it has.
The Bowline on the Bight has a long track record as a rescue harness, and many lives have been safely entrusted to this knot. If you know how to tie the basic Bowline properly then this is a fairly easy knot to remember how to tie, it is quick and easy to tie and dress (more so than the Double Figure-Eight Loop), and it can be tied in the middle of a rope when you don't have access to the ends of the rope. It is also easy to untie after it has held a load. Its strength rating is generally regarded as being 10-15% less than the Double Alpine Butterfly or the Double Figure-Eight Loop, but again, it has a long track record of safely being used in rescue situations.
The Double Figure-Eight Loop is preferred by many climbers rather than the Bowline on the Bight, although it seems that climbers sometimes use the Double Figure-Eight Loop in some situations and the Bowline on the Bight in other situations. The Double Figure-Eight Loop is generally considered to be strong and secure, and in my experience it is easier to untie than the basic Figure-Eight Loop.
The Double Dragon seems to rival the Alpine Butterfly in many ways, and the same seems to be true for the Double Double Dragon. It is easy to tie, and it is also easy to convert a single-loop Double Dragon to a double-loop Double Dragon (and a double-loop Double Dragon to a triple-loop Double Dragon). The Double Double Dragon can be tied before using the two loops, or the two loops can be tied around an object while the knot is being tied. However, it appears that it can jam and be difficult to untie if both ends of the rope have been under a strain.
ABOK #1100 is Ashley's splayed double loop based on the Alpine Butterfly. For certain applications, people sometimes prefer using splayed loops rather than loops which lay on top of each other.
The Double Alpine Butterfly does not seem to be widely known. It seems to have the same basic strength rating as the Alpine Butterfly (the core knot configuration is the same), and it is easy to tie and untie.
Be sure to practice tying your favorite knots periodically (from different angles) so that you'll know how to tie them when you need them.
The purpose of this series of articles is to try to boil the thousands of knots down to just a few of the best rope and string knots that can safely be used for a wide variety of purposes. People such as climbers, sailors, search-and-rescue workers, etc., have their preferred knots, but for the average person it is probably "overkill" to try to learn and remember a variety of double-loop knots. Just as the Alpine Butterfly is my preferred single-loop knot, the Double Alpine Butterfly is my preferred double-loop knot. Sticking with the same basic knot (such as the Alpine Butterfly) makes it easier to remember how to tie a single-loop knot or a double-loop knot when you need them. If you are an "average person" who doesn't need specialized knots (such as the kind that climbers, sailors, and so on, might need), then the Alpine Butterfly family of knots (single-loop, double-loop, triple-loop, and bends) should serve you well in a variety of situations.
For other people's preferred knots, see the topic called "Best of breed" knots? at the forum of the International Guild of Knot Tyers.
Here is a list of the articles in this series. Every link will open up in a new window to give you more control as you browse around in this website:
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Modification History
11/17/2006: | Added a link to my new page called "Dave's Websites." |
10/17/2005: | Added the ABOK # to the list of names for each knot (based on Clifford Ashley's The Ashley Book Of Knots). Added the ability to download this entire website (all 9 articles) in a single .ZIP file. |
01/29/2005: | Added a new method for tying a Double Alpine Butterfly. Special thanks to my 10-year-old son Michael for lending a hand! |
01/13/2005: | Modified some of the wording throughout the article. Added ABOK #1100 (Ashley's double loop based on the Alpine Butterfly). Changed my preferred double-loop knot to the Double Alpine Butterfly, and added a link to the forum of the International Guild of Knot Tyers in which other people have described their preferred knots. |
05/10/2004: | Added a new method of tying the Double Double Dragon (and other multi-loop versions of the Double Dragon). |
04/15/2004: | Added a new knot called the Double Double Dragon. |
09/01/2003: | Added new pictures of the Double Alpine Butterfly. |
12/10/2002: | New article. |
Dave Root
Send e-mail to: dave@Layhands.com