Thank you very much for making this! This will probably help many people. Very well written and organized too.
professionally written with good info. i am impressed. however, i would however like to dispute one or two points.
There is some debate over whether the klemheist will grip in both directions, the textbooks seem to say no, but i've found otherwise and i know of at least one guide service that uses it almost exclusively over the prusik because of how ridiculously long you can spent tending a prusik to get it exactly right so that it will actually grip, which i was glad to see you noted as a downside of that knot.
is there really research that says girth hitching lowers the breaking point of a sling? if so could you send me the link, because i was under the impression that girth hitches were one of the only knots that did not lower the breaking point (i girth hitch a lot of stuff, so this is sort of scaring me).
Thanks. Very interesting about the klemheist, thanks for sharing that. I've messed with it alot and have seen how it could hold both ways, but it's always made me nervous trying it since visually it looks like it only goes one way.
With the girth hitch it's strength is reduced when it's used to attach sling to sling. Here's an article by Black Diamond on testing girth hitched slings...
...One of their main conclusions was...
"Joining two slings reduces the ultimate strength—and in some cases by up to and over 50%"
What I mentioned above was that I've seen and heard differing opinions on if the orientation of a girth can effect its strength. I've never seen a final report or article but basically the argument is that a straight orientation like this...
...is stronger than a twisted orientation like this...
Excellent article. Good selection of hitches and you kept the text short. I would agree learn these all, but go with the one you're most comfortable with for a particular situation. For example, either prusik above rappel device or autoblock below for rappel self-belay/backup. Practice, practice, practice.
Articles like this are amongst the finest additions on SP. Thanks for taking the time to put it together and excellent job too.
An excellent article. Being a 'newish' climber, I have only tied and used the clove, girth, and Munter hitches. I am going to practice tying the other ones you show.
Thanks to have updated your article adding the name of Machard to the Autoblock hitch. I will send you info on some variants that can be quite useful and so worth knowing, the "French" hitch, the Braided Machard and the single loop Machard also called the Valdotain knot which can be most useful in an emergency as well as the Polish knot.
Note that the Prusik is not used any longer by the French guides and most French climbers (I do not know about other European guides syndicates but my guess is that it must be the same as knots such as the Machard are so much easier to make and do not stiffen as much).
I will add an obvious recommendation with the usage of autoblocking knots particularly when abseiling : use a cord 2 mm smaller than your climbing rope and avoid a diameter below 6 mm, 5 mm is considered as the security limit (due to the Nylon melting limit).
There is also the tricky issue of should the autoblock knot be above or below the abseil device?
It seems that all English and American climbers have chosen the below position while the French ENSA have not decided any either ways. I guess the advantage should go to the Anglo-saxon's view as they were first to invent the abseil devices.The below position which I have been personnally using has a number of significant advantages (the abseiling device used higher gives more braking power, unblocking the autoblock is easier as a shorter cord means less tension, you can use a free hand to unblock yourself or the abseil rope...) so is less tiring and you can abseil faster but both methods have inconvenients and as Augie Medina stated, the solution is to practice, practice to counter them.