The hows and whys of tying in with a Bowline

Ondra Dawn Wall
Bowline enthusiast Adam Ondra, shown here getting super-psyched about bowlines (Photo by Heinz Zak)

If you’ve ever wept tears of inadequacy onto a welded knot after a big whipper (or a series of smaller ones), you’ve probably wondered if there’s a better alternative than the ubiquitous Figure 8. Some climbers opt instead a variation of the bowline, but as an alternative, is it superior? The answer is the same as with many climbing conundrums – it depends.

Although bowlines have been used for centuries (maybe even millennia) in nautical applications, it’s use in climbing is something of an anomaly. This rarity has occasionally created a certain brand of stigma and even led some to denounce the bowline as a death knot. That’s not necessarily true – while the Simple Bowline is indeed unsuitable for tying in, there are certainly variations which are safe and effective.

But which variations? And why? The internet is pretty much the Wild West in terms of reliable technical information on climbing techniques, more of a repository of opinions than facts. For what it’s worth, let’s try and wade through this particular quagmire and see if we can’t shed some light on this most ancient of climbing questions – should you tie in with a bowline, and if so, which bowline is best?

For reference, I have relied heavily on An Analysis of the Structure of Bowlines by Mark Gommers of PACI (Professional Association of Climbing Instructors). This is a very thorough treatise by a passionate knotsman, so if you’re looking for a more in-depth analysis, you can download his masterwork on the subject here as well as other similar technical manuals. My article is an attempt to condense and summarise this information for the layperson, and I welcome any corrections, inclusions or amendments.

What is a Bowline?

Before we go any further down the rabbit hole, let’s define what we mean by the term “Bowline”.

Even The Ashley Book of Knots, which is considered by most knot aficionados to be vastly more sacred than the Holy Bible, is a little vague on defining exact characteristics of bowlines. These days, experts largely agree that a bowline (or variant thereof) is defined by three essential components:

  • A Fixed Eye (which does not move, as compared to a slipknot)
  • A collar (which captures the standing end), and perhaps most importantly,
  • A nipping loop (which is free to compress with application of load)

In general, when people refer to a “bowline”, they refer to the “Simple Bowline” as seen in the image above. This knot carries the designating number of #1010 in the Ashley Book of Knots and was invented for maritime purposes and was never intended for climbing contexts. In the interest of disambiguation, this article adopts the following conventions – that “a bowline” refers to any type of knot sharing the characteristics mentioned above, whereas the term “Simple Bowline” refers specifically to the #1010 knot . Variants will be referred to by their respective titles.

What are the advantages of bowlines?

One advantage of bowlines is that they are Post Eye Tiable. Unlike the Figure 8, they can be tied in a single-stage process, meaning that it isn’t necessary to form the knot before feeding through the harness. This also applies in reverse, such that when a bowline is untied, it leaves no “residual” knot which has the potential to become stuck if pulled through the anchor in a moment of inattention.

But the main advantage of bowlines in a climbing context is that they are easy to untie even after significant loading. Gommers observed that the collar of the End Bound Single Bowline (EBSB) was able to be manipulated under 10kN of force, which is to say that you can place a metric ton of force on the knot and still shift the collar by hand. By way of comparison, a Figure 8 will jam when force on the knot exceeds 4kN.

This means that, for all intents and purposes, the knot is easy to undo under any and all scenarios to be expected in a lead climbing context. I propose that if you have generated a force up to or exceeding 10kN during a fall, you probably have bigger things to worry about then how welded your knot is.

What are the disadvantages of bowlines?

The major disadvantage of the Simple Bowline is that lacks the security of the Figure 8, given that it has a tendency to work loose unless kept under constant tension. This, of course, is common in a climbing scenario, where the knot experiences alternating periods of tension and slackness, otherwise known as cyclical loading.

The way around this problem is to tie a more secure and stable variant. There are a few, and we’ll examine them in detail soon. The disadvantage to these knots is that they are often harder to tie and harder to inspect. Given that most climbers are more familiar with the Figure 8 as a tie-in knot, most belay partners will generally have no problem identifying faults at a glance. The same can’t be said for bowlines with their seemingly endless variations, and therefore the use of these knots to safeguard a fall carries a higher level of personal responsibility and risk for the user. That said, self-reliance is a key attribute in the sport of climbing, and those who are confident and practiced in tying a bowline should feel no reluctance in its use.

Are bowlines strong enough for climbing applications?

In a word, yes. Some have made spurious claims as to the inherent weakness of bowlines, but it should be remembered that all knots weaken cordage to some extent. During his relentless examination, Gommers tested the breaking strain of the EBSB and observed it to be approximately 75% as strong as the minimum breaking strength of the cordage as quoted by the manufacturer (Sterling, for those playing at home). When compared with the Figure 8, which has been observed by many tests to be 75-80% as strong as the minimum breaking strength, this represents slim to no difference. Nothing to see here, folks.

What are the methods of failure?

There are two main methods of failure with the Simple Bowline, and these methods of failure can help point us in the right direction when deciding which variants might be more suitable.

The first is when the tail works its way through the knot, either by cyclical loading, ring loading or slack shaking, all of which occur in varying amounts during climbing. The second is through rupture or failure of the nipping loops. Of the two, the latter is a less important consideration given the strength assessments made above, but it is still worth note. Bowline variants which are suitable for climbing solve both problems by some combination of the following methods:

  1. Securing the tail (either by virtue of the knot itself or in conjunction with a Double Overhand AKA Half Fisherman’s)
  2. Showing resistance to ring loading
  3. Increasing the number of strands captured by the nipping loop (which increases friction on the tail, as well as increasing the radius of the loop and thereby lessening the stress caused to cordage by sharp bends)

Only “secured” bowlines should be used in life-critical applications, and the simple bowline is not one of these. By definition, any knot that requires additional tail manoeuvres (e.g. tying a Double Overhand) to lock down the structure is not inherently secure, and only those which are inherently secure by virtue of the knot itself are suggested later.

There has also been a proposed method of failure in which the collar “capsizes”, similar to the failure method observed on the Offset Overhand Bend (AKA Euro Death Knot). This, however, has not been observed and replicated in any manner which would conclusively confirm this method.

Which variations are suitable for climbing applications?

Let’s take a look at which bowline variants which have been proven to be stable and secure. All offer ease of untying after loading, and therefore they present themselves as viable alternatives to the Figure 8.

Scott’s Simple Lock Bowline

Scott’s Simple Lock Bowline
Source: An Analysis of the Structure of Bowlines, Mark Gommers

Lee’s Locked Yosemite Bowline

Lee's Locked Yosemite Bowline
Source: An Analysis of the Structure of Bowlines, Mark Gommers

End Bound Single Bowline

EBSB Bowline
Source: An Analysis of the Structure of Bowlines, Mark Gommers

Each of these bowline variants has been tested and shown to be secure… but that doesn’t mean you shouldn’t test them yourself! Before trusting your life to any of these knots, you should verify their efficacy in a safe environment and ensure that you are thoroughly familiar with their construction.

Look, should I tie in with a Bowline or not?!

Personally, I still use a Figure 8. It’s not because of any prejudice or phobia, it’s simply what I know best – I am confident that I can tie a Figure 8 correctly, even when I’m exhausted and it’s dark and there are boogiemen around. But that all comes down to muscle memory and familiarity. If you’re committed to forming that same familiarity with a secure bowline variant, then there is no good reason you shouldn’t.

If the style of climbing you enjoy most doesn’t involve regular falls (e.g. ice climbing, mountaineering, adventure trad), you probably don’t need to make the change. But if you find yourself climbing hard sport and projecting a great deal, you might find a bowline to be a superior choice.

Ryan Siacci, Esq.
February 2019

Remember, folks – climbing is dangerous! The above information should not be considered a definitive work, but rather an overview. Mistakes and omissions are possible, and the use of the information contained in this document does not imply responsibility to the author for death, injury or harm that may result. Always test your knots before use and consult a professional climbing guide for guidance.

  1. Great article Ryan, really enjoyed the read! You mentioned this in passing towards the end, but I’ve not heard of it being studied in detail – how vulnerable are the different tie-in knots to misidentification/incorrect tying? Has anyone attempted to quantify failure rates through incorrect knot tying by knot type?

    1. Thanks, I’m glad you enjoyed it! I generally write whatever nonsense I feel like writing, so writing technical stuff with researching and fact checking is much more time consuming, but the results are rewarding.

      Your question is a very good one. Reliable climbing data is thin on the ground, and my guess (without actually knowing 100%) is that the reliable data on that particular chestnut will probably not exist. Leave it with me and I will see if I can uncover anything useful! Thanks for the idea 🙂

    2. Hi mate, just a follow up to your question, and the short answer is no. There is some limited data from a 2016 German study on climbing gym accidents, and the findings reported that “the most serious crashes were all due to mating failures – a proper and consistent partner check could easily prevent such accidents”. This could potentially allude to methods for attaching to the rope, but the study is unclear. What is clear, however, is that you should check yourself (and your buddy) before you wreck yourself.

  2. Ryan, it appears that you have edited your original content – thus removing several glaring inaccuracies. God to see that you have taken on board my advice.
    However, some inaccuracies remain – but, given the fact that the subject area of ‘Bowlines’ is incredibly complex – you have written an article that is better than most.

    Here are some points that you should include/edit – to further improve your content:
    1. The primary advantages of all ‘Bowlines’ is that they are Post Eye Tiable (PET) and totally jam resistant. There is no load test that has managed to induce jamming. In contrast, #1047 Figure 8 is neither ‘PET’ nor jam resistant. The #1047 F8 will jam when loads reach the vicinity of 4kN-5kN (depending on rope material and knot dressing).
    2. Stop calling #1010 (from ABoK) a ‘standard’ Bowline – instead, refer to it as a ‘simple’ Bowline. The simple #1010 Bowline is not suitable for human fall-arrest purposes. And that’s perfectly fine because the #1010 simple Bowline wasn’t intended for climbers! It was invented/discovered by sailors and it is perfectly fine for use on a sailing vessel. And this is a key concept…so I’ll repeat it again: The #1010 simple Bowline was intended for use at sea on sailing vessels – it was never intended for rock climbing and/or mountaineering.
    3. The argument that ‘Bowlines’ are harder to inspect/check is tired and irrelevant. It comes down to practice (and training). People make mistakes tying-in with #1047 F8 (I refer you to the accident reported by Robert Chisnall (17 September 2015 at Lac Larouche, Quebec Canada) where a female climber failed to properly tie her Figure 8 tie-in knot to her harness. The issue is that content writers like to report instances of tie-in mistakes with certain knots that promote their views. The fact is that anyone can make a mistake with any knot – human error is always a factor. How do you eliminate human error? Look at vehicle accidents in Australia and around the world – put a human behind the wheel and you have potential for mistakes. Another point I would like to make is that innovation and progress should be encouraged – not discouraged. The progress that I and several others have made with ‘Bowllines’ is due to the fact that we were prepared to innovate and explore new ideas and new ways of solving old problems.
    4. Knot strength is irrelevant – it is an urban myth. You mention in your content that I load tested some ‘Bowlines’ – and found them to be in the vicinity of 75% of their unkotted yield strength. Any load testing that I (and my colleagues) do is purely for academic reasons – to probe and investigate the effect of geometry. It is NOT to declare knot A versus knot B in a pull-it-till-it-yields test and declare the winning knot as somehow ‘better’ than the ‘losing’ knot. Often, the ‘losing’ knot is superior! Load testing is simply a tool to investigate the behavior of a knot structure under various loading profiles (eg hoop/circumferential loading of an eye).
    5. My final point is related to point #2 above. When people use the term ‘Bowline’ – what exactly do they mean? Some content writers have their own agenda and like to sensationalize their story. So they throw around the term ‘Bowline’ as if it were a catch-all phrase to demonize all ‘Bowlines’ as being ‘unsafe’. When I read such articles, I laugh inwardly at the poor level of understanding by the content writer. The fact is – there are many different types of ‘Bowlines’. As you have correctly pointed out – some ‘Bowlines’ are inherently secure while others are not. The #1010 simple Bowline is NOT inherently secure. And it is critically important to understand that there is nothing wrong with that fact – there is nothing sinister going on. It is perfectly normal for the #1010 simple Bowline to be both insecure and unstable! It wasn’t intended for rock climbing. And so it is nothing short of idiotic to declare ‘Bowlines’ as being unsafe by pointing to the #1010 simple Bowline as the prime example. There are now (discovered) several ‘Bowlines’ that are inherently secure. Inherent security means that no further action is required to render the knot stable and secure. That is, no further tail maneuvers are required to lock down the structure (eg by adding a further ‘stopper / backup’ knot). If you need to add a ‘stopper / backup’ knot – by definition, the knot isn’t secure and stable.

    Mark Gommers 23 April 2019

    1. Hi Mark,

      Thanks again for your input, it’s certainly welcome! I will briefly respond to each of your points:

      1. Good information, I have now amended the article to include this.
      2. Agreed. I have modified the naming convention of the knot.
      3. I respect your input on this but I personally still see relevance in it. In a perfect world, you are right – everyone would be all over bowlines and their variants. But it’s not a perfect world, and although I don’t think people should shy away from perfecting their own knots, many climbers (myself included) wouldn’t be able to check the efficacy of someone else’s bowline variant beyond a shadow of a doubt. Therefore, I believe it’s worth noting that tying in with a bowline has a slightly different risk profile than tying in with a figure 8, a knot in which essentially all climbers are familiar. To me, it’s a bit like the argument for veganism – one can argue until they are blue in the face that everyone should go vegan, and yet we know that the majority of the world never will. Figure 8’s are the steak dinner of knots.
      4. The article 100% dispels the myth of strength being a factor, and I keep the information in there to actively fight that myth.
      5. I have done my best to give a laypersons understanding of the need for “inherent security” without labouring the point too much. I feel as though the article has achieved that, and for those who require or desire further information, I have pointed them toward your manifesto on the PACI website.

      Thanks again, Mark, not least of which for all the effort that went into the original document and the subsequent updates.

      1. I recommend that you review the paper on ‘Bowlines’ at this link: (at #2 in the table).
        The paper has been fully revised and updated and includes detailed information about all of the inherently secure Bowlines.

        I note the long favored and over labored argument re ‘checking a tie-in knot. I have address this issue on the updated paper.
        Briefly, the concept of ‘not being able to check and verify a particular knot’ – is untenable.
        A quick snap-shot reply is ‘rope solo climbers’ – who checks them?
        One would presume that ‘they’ could select and use any knot they desire.
        Another quick fire response is with professional Guides. Many Guides work alone with their ‘client’. That is, its often just the Guide + client and no one else. Holding that thought – it would be meaningless for the Guide to ask the ‘client’ to check and verify the Guide’s knot! Typically, the ‘client’ is a total novice who is just along for the fun and thrill of the climb.
        Another point – Merely because another person doesn’t know a particular knot does not make it unsafe. That’s a ludicrous proposition.
        Of far greater importance is the competence and confidence the climber has in his/her own skills. There are 4 levels of competency as follows:
        1. Conscious competence; and
        2. Unconscious competence; and
        3. Conscious incompetence; and
        4. Unconscious incompetence.

        Lead climbers (in particular) need to be ‘consciously competent’. That is, they are cognizant of the fact that their knowledge and skills are entirely correct at all times.

        Unfortunately, there are quite a few climbers out in the wild who are either unconsciously incompetent (they don’t know that their skills are lacking) or consciously incompetent (they are fully aware of their lack of experience/skill – but choose to run the risk anyway).

        In the recreational climbing community – knowledge and skills are typically passed on by word-of-mouth of by trial and error learning at the crag. Knots skills in particular are often learnt by simply watching and then mimicking others – or from reading books (which are often totally inaccurate) or browsing the internet.

        This is one of the reasons why I am releasing my technical papers into the public domain (free-of-charge)…to provide a technically accurate reference material which will hopefully filter through to the masses and improve our collective knowledge.

        Mark G

  3. Perhaps it would be good to write more about the bowline variants climbers actually use, as I haven’t seen those above in the wild. For example I like the bowline on a bight “ABoK # 1080” (tied by rethreading through the harness) which is an easy knot to learn and check for anyone who already knows a simple bowline.

    To be clear I believe in self-reliance and am not worried about my partners being able to check my knot, but do worry about my own learning and remembering abilities. In practice I find the process of partner checking is the important thing – generally they look down, say “I don’t know your knot” and then I check it myself. It might even be worth highlighting that this process is still useful and should always be kept up, even when you don’t know your partner’s knot.

    On the other side, Mark Gommer’s paper says the common Yosemite bowline is not as secure as some believe, and has an easy method of mistying.

    1. I think the issue is that the bowline variants that people generally use are actually a bit shit for reasons stated in the article. The research is all here, but what climbers choose to do with it is entirely up to them. I personally still use a figure 8.

Thoughts? Opinions? Cries of dissent?

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