UKH

I'm watching the BMC Alpine essentials DVD and reading through the UKC Alpine skill series and there are 2 different methods for re-directing force from the tied off coils to the harness:

BMC Alpine essentials; prussik > screwgate > snapgate > belay loop

UKC; clove hitch > screwgate > belay loop

https://www.ukclimbing.com/articles/skills/series/alpine_skills/glacial_tra...

Are there genuine advantages to the prussik method I'm missing? To me it risks shock loading (if there's any slack) a prussik and it seems bizarre to add the snapgate in at all especially to a screwgate.

The prussik is there to keep the weight at your waist if the other person falls. Then if you fall ‘all you have to do’ is slide up the prussik so you stay up right. It’s a bit messy is the downside I guess 

There are many ways to tie coils for glacier travel and the method you use may vary according to the state of the glacier / conditions / number on the rope / experience of group / knowledge of the terrain / your own knowledge etc. Both the methods shown are excellent ways of tying off the coils.

    The clove hitch method is neat and tidy, quick and completely appropriate if the crevasse risk is relatively low. For example early morning after a good freeze with obvious or known crevasses, a short distance to travel and possibly three or more on the rope.

    Sometimes the snow is softer ( later in the day perhaps ), there are more or hidden crevasses, you are in an unknown area to you, two on a rope ( more risky than three or more ), fresh snowfall hiding crevasses, tiredness at the end of a long day, a long glacier crossing and possibly less or no people about. In any of these cases the risk is higher so a more cautious approach would be to use the prussik loop. Firstly, with a fall into a crevasse the combination of 12-15 metre plus dynamic rope between you and your partner and the likelihood of a slide before stopping of the person holding the fall means the shock load on the prussik is unlikely to be a problem. Should a hauling system be required then having the prussik already on the rope to attach it to an anchor saves time and effort ( it can be very difficult to set one up in a 'real' scenario) . The extra snapgate carabiner shown has two uses that are explained in the Alpine Essentials video: Firstly it creates the right distance for the prussik to be loosened in order to transfer weight to the chest coils as well as the harness if required and secondly it is much easier to undo.

    I strongly suggest learning various different methods and trying them out, especially on a wet glacier  with safety back up, so that you are confident that all members of the party know what to do.

Hope this helps.

IMO, although true, that's over complicating matters.  Either there is a risk or there is no risk. You either tie on or don't tie on. I'm afraid I don't agree with the concept of degrees of risk on a glacier. It's been a while and I'm sure techniques have progressed but we just tied on with an overhand or F8 knot to a screw gate krab on the belay loop.

Al

Thanks that's useful. Having watched and read further, the prussik method means if a fall does occur you just adjust weight into chest coils. It's definitely an advantage there as doing so from the clove hitch is more difficult. 

Further downside, prussics dynamically loaded can cut the rope. So too can a clove hitch...

I've personally tried normal prussics, mechanical prussics, tied off belay devices and clove hitches. All of them are equally valid. If I was traveling largely wet glaciers at the beginning of the season I'd probably opt for the prussic if I intend to pitch and move together efficiently and its above my solo zone, or that of my partner's then the belay device is good. Otherwise clove hitched on.

I recommend trying them all, at the very least it will teach you more. 

The advantage of the prusik method is that it transfers the direction of pull down to your harness where it is more in line with your centre of gravity, making it less likely that you'll be pulled off-balance if your companion goes down a crevasse. It also means that you are already set up for a rescue.

The simple tie-off is quicker, especially in a situation where you may be putting on and taking off coils.

As the article itself says, there are lots of different methods.