16

There seems to be conflicting information on the web about how to use a Munter hitch for belaying and rappelling while rock climbing. The way I learned decades ago is consistent with Nols Wilderness Mountaineering by Phil Powers:

The Munter hitch differs from a belay device in that the braking position is forward, toward the anchor, rather than back toward the hip. If you rappel using this hitch, be careful to use the Munter with the load strand close to the spine of the carabiner.

A number of videos and blogs suggest that the Munter should be tied with the load strand close to the gate and the break position down towards the hip. They even use an autoblock to back it up and force the downwards break position. (I am not providing links on the off chance I am correct and the information is bad). Have there been new developments regarding the use of a Munter hitch for belaying and rappelling?

Improve this question
8
  • I don't see why it would matter whether the load strand is closer to the gate or closer to the spine. Since FotH illustrates it the opposite way compared to what Powers says, this seems to confirm that it doesn't matter. This is probably similar to the question of the orientation of the carabiner when using an ATC; many people have opinions or their own habits, but there is no clear evidence (that I know of) that it matters, and experienced, knowledgeable people do it different ways.
    – user2169
    Commented Mar 2, 2016 at 15:32
  • @BenCrowell Yeah, I find it odd too. If it weren't a locking carabiner it would be more of an issue, but I wouldn't use this know at all with a non-locking carabiner.
    – Roflo
    Commented Mar 2, 2016 at 15:35
  • The fact that people use an autoblock when rappelling with a Munter does not mean that downward is the strongest braking position. The figure from FotH reproduced in DudeOnRock's answer claims that you still get 75% of the maximum braking force in this position. You don't want or need 100% of the braking force when you're rappelling. 100% of the braking force is enough to catch a hard lead fall, which is many times greater than what is needed in order to stop your rappell and hold body weight.
    – user2169
    Commented Mar 2, 2016 at 15:36
  • @BenCrowell maybe I am missing something, but isn't downwards the least amount of friction? I agree that when rappelling with a Munter sometimes there is too much friction and it is difficult to move.
    – StrongBad
    Commented Mar 2, 2016 at 15:43
  • @BenCrowell at a minimum, if there is no difference in the chance of unlocking the gate, there is a slight strength difference between spine and gate sides (and in my experience there is a big difference). I have never seen debate about the "fact" that a clove hitch should be tied so the weighted end is next to the spine.
    – StrongBad
    Commented Mar 2, 2016 at 15:45

2 Answers 2

Reset to default
12

To answer your question as to the ideal break position when using the munter: It depends. It depends on your comfort and experience with the knot, its application and the situation.

I have rappeled and belayed with munter-hitches on numeral occasions.

  • A double stranded munter-hitch rappel provides a significant amount of friction and unless you want to come to a complete stop you will probably be breaking by your hips.

  • For single stranded rappels, especially on thin ropes breaking at the hip instead of towards the anchor can be disconcerting. It is doable though, and it is nice to at least know that lifting your arm will stop you.

  • If you are rappeling with a load, either in a rescue situation or with a haul-bag, I would highly recommend breaking towards the anchor, at least until you have gotten used to the situation. If you want extra safety in situations like those, check out the Double Munter, which lets you manage heavier loads and has the added benefit of not twisting your rope.

  • I would say top-rope belaying, mentioned here for completeness, is the most awkward of applications, since you have to pull rather than release the rope through a shifting knot. I would say it is pretty unlikely you will be doing that for long by pulling towards the anchor, since that is super tiering. Belaying a leader from the ground is slightly less awkward, but still not as nice as belaying from the top, where the munter shines at its best.

The following illustration is from the climbing and mountaineering bible Freedom of the Hills, which by the way every aspiring climber should have in his or her bookshelf.

illustration of a Munter hitch taken from Freedom of the Hills

Learning the munter is absolutely not optional. It has saved my behind a couple of times when I have cast off without a belay device.

I wouldn't recommend using the munter though unless for practice or in situations when absolutely necessary, since it turns the rope into a twisted mess.

Improve this answer
4
  • 2
    The picture also shows the weighted end next to the gate. I have never seen a "knot" with so much disagreement.
    – StrongBad
    Commented Mar 2, 2016 at 12:02
  • I have had it confirmed by three professional instructors (two in person, one in a video online) that 0 degrees is the strongest braking position. Of course that's not actually an independent confirmation, because they're probably all getting their information from Freedom of the Hills.
    – user2169
    Commented Mar 2, 2016 at 15:40
  • 1
    @BenCrowell I am pretty sure physics supports the claim that the 0 degree position has extra holding power since it has an extra bend. It would be nice if there was a reference with actual measurements.
    – StrongBad
    Commented Mar 2, 2016 at 15:47
  • Yes, I agree that it's physically plausible. We expect tension to go like exp(mu theta) as a rope is wrapped around a cylinder, so here we should get an extra factor of exp(pi mu). The nylon sheath of a climbing rope on an aluminum carabiner probably has mu of approximately 0.15. (It's not easy to measure accurately or reproducibly.) This gives exp(pi mu)~1.6, which seems roughly consistent with the diagram from FotH claiming 4/3, as well as with requiem's data. (A mu of 0.1 reproduces those numbers better.)
    – user2169
    Commented Mar 2, 2016 at 20:35
10

A Munter hitch can brake regardless of the orientation of the brake strand. It provides the greatest braking force in the "closed" position (the brake strand running alongside the load strand), and a lesser force in the open position. The first site I found with testing found the following brake force values (tested with 11mm rope):

  • Easy one-handed braking: 0.9kN open, 1.2kN closed.
  • Both hands, solid stance: 1.9kN open, 3.4kN closed.

Reviewing to Table 3 from a DAV Panorama article testing belay device loads, this is comparable to other belay devices and inline with numbers reported elsewhere around the internet (~2.5kN in the closed position). Unfortunately I was unable to locate previous test reports.

The positioning of the load strand relative to the spine tends to vary across the literature, in some cases both forms may be depicted in the same book. There are potential arguments for either position; the strongest in my opinion being that having the brake strand closest to the spine keeps it from inadvertently rolling over and unscrewing the gate of the carabiner. (Or the gate may have edges that could damage the running rope.) Testing done on the clove hitch (a structurally similar knot) show no strength benefit to placing the load strand closest to the spine.

If you are using the recommended pear-shaped (or HMS) carabiner for the munter, the positioning of the load strand will tend to end up in the "belly" of the carabiner regardless of the brake strand orientation. Refer to some of the pictures here in the "Carabiner shape" section: http://www.ropelab.com.au/munter-hitch/

Side note: The Outdoor Knots Book by Clyde Soles mentions that the twists a Munter is often accused of creating comes from a case of "pilot error" -- when the brake strand is held out to the side. Keeping the rope parallel is said to reduce or prevent this. Ironically enough, other sources have listed contradictory advice. (I have no data as to which is correct.)

Improve this answer
4
  • 1
    On your side note: At least when lowering the climber it matters certainly: If you feed the rope in holding it parallel you get the usual (so moderate) amount of twists when using a Munter hitch. When feeding from the bottom you immediately get really bad twists. I teached a childrens beginner climbing course using the Munter hitch the past few months and it was an issue...
    – imsodin
    Commented Mar 2, 2016 at 19:04
  • Nice answer. But: having the load strand closest to the spine takes full advantage of the strength of the carabiner This doesn't make much sense to me physically. Unless there is test data to support it, I would not believe this claim.
    – user2169
    Commented Mar 2, 2016 at 20:40
  • 1
    @BenCrowell I was struggling with the wording, but the idea was that it exerts the least leverage on the basket arm. For example, a nose-hooked 'biner can fail at loads under 2 kN. Of course, nose-hooking usually involves the gate being open as well. For practical use, the alignment of the load strand on clove hitches and munters doesn't seem to matter in terms of strength. Supporting your suspicion is: mikemclean.ca/ocd/wp-content/uploads/…
    – requiem
    Commented Mar 2, 2016 at 22:03
  • Interesting link, thanks. Based on that, I'd suggest deleting the sentence in your answer that we've been discussing.
    – user2169
    Commented Mar 2, 2016 at 23:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.