Using a prusik knot for safety on an abseil is a very well-known and common technique that many climbers use. But this tip is just a little ‘icing on the cake’ for that technique, which far fewer people seem to use routinely, or perhaps don’t even know.
A Prusik Knot?
First, a little digression. What sort of knot is it? Prusik? Prusic? Prussic? Prussik? Prussick? Prusick? Prozac? We seem to use an endless list of spellings.
Well, the clever little grippy-slidy knot was first invented by the Austrian mountaineer Karl Prusik so we should pay him the respect of spelling his name correctly, I suppose.
Since his original knot, first shown in an Austrian mountaineering manual in 1931, there have been a number of variations and developments of the concept. We now have additions to the family such as the ‘French Prusik’ and the ‘Klemmheist knot’. I’ll post another article in the future looking at the pros and cons of each one. However, we generally refer to them all under the umbrella of ‘prusik knots’.
As far as this tip is concerned, it doesn’t make any difference which variety of knot you are using to act as a safety back up on an abseil.
Instead of using a prusik knot, an alternative approach is to get a partner who has already descended to provide a safety back-up for you.
Protecting an Abseil with a Prusik Knot for Safety
This is not a ‘how-to’ article, starting from first principles. I’m assuming as a start point that:
- You can already abseil.
- You can set-up an abseil, almost certainly retrievable, in a climbing/mountaineering context.
- You recognise the benefit of using some sort of safety back-up during an abseil to protect yourself in the event that you let go of the rope.
- You already carry prusik loops and use a prusik knot to perform this safety function when you abseil.
There are a variety of different set-ups that can be used, and have been used over time. However, the most common set-up in use today in the UK is for the abseil device (probably your belay plate) to be attached to a sling rather than the harness. This extension sling positions the abseil device at around chest height.
The safety back-up prusik is attached to the rope and directly to the belay loop of the harness, below the abseil device.
Sequence of Setting up Abseil and Safety Prusik
The essence of this tip is not about the actual set-up, but it’s about the sequence that you use when setting it up.
The list of potential contexts for this is huge, so again I’ll cut straight to the heart of this tip. Let’s now assume that you, the climber, are ready to attach yourself to the abseil rope with both your abseil device and your safety prusik.
Common Sequence for Setting up Abseil with Safety Prusik
It’s very common to see the climber attach their abseil device (belay plate) first and then attach the safety prusik. I can see a sort of logic here. The abseil device is the ‘main event’ and so folks probably focus on that first. The safety prusik, which hopefully won’t come into play, is ‘just a back-up’ and gets fitted afterwards.
However, the drawback of this sequence is that in order to fit the rope into the belay plate, the climber has to lift the weight of the ropes while creating slack to pass a bight through the device. If you are using two 60 metre ropes, that’s a fair weight of rope to lift. Any fumbling is likely to result in a dropped belay plate, and all the additional hassle that will then follow on from that.
So, here we get to the Tip.
Better Sequence for Setting up Abseil with Safety Prusik
The best sequence is to fit the prusik first and then fit the abseil device afterwards. Why is this? Well, having fitted the prusik to the rope and the harness, you can then pull plenty of slack through the prusik. The weight of the rope below will now be hanging from the prusik on your harness, and there will be a (small) pile of slack rope on the floor. This slack rope is then dead easy to fit into the abseil device.
Once the abseil device is fitted, you can then pass the rope back through the prusik. The prusik will then end up in its correct position for abseiling, that is gripping the rope below (and well clear of) the abseil device. You are now ready for your final safety checks before setting off downwards.
A simple but effective change to the sequence massively reduces the chance of dropping your abseil device.
- Ignore the spell-checker on your computer. Refer to the grippy-slidy knots by the name of the person who invented them – Prusik.
- Always use some sort of safety back-up when abseiling, in case you let go of the rope. In a climbing and mountaineering context, the answer is almost certainly some sort of prusik knot.
- Fit the prusik knot first and the abseil device afterwards. This will massively reduce the chances of your dropping the abseil device while you try to fit the rope into it.