Apologies to anyone who has come here expecting to find a cute children’s story, crustacean psychotherapy or information on cynical old men, you’re going to be disappointed.
A crab in this context is meant as a shortening of carabiner, the ubiquitous climbers tool. The reason it is pessimistic is because it is the one I use to carry all of the things I might need if it all goes wrong.
I've done a lot of multi-pitch climbing. I love long routes but the commitment involved means that you need to be a little more prepared than at a single pitch crag. If you have a problem on route, you can’t always just lower off sort it out.
My pessimistic crab is that preparation. It clips onto the back of my harness, out of the way and acts a safety blanket. It is a full-strength screwgate and it contains the following;
A couple of Prussik loops made from 5mm cord. I use a metre of cord to make a loop about 40cm long. Other people use longer or shorter. I have two so I can ascend the rope in an emergency but mostly they are used to protect abseils.
About 4 metres of 10mm tape. Some people carry more, some less, some thicker, some smaller. It’s up to you, but think about the type of rock you climb on and the size of the spikes/threads you might be retreating from.
If there is any chance I could be caught out after dark I’ll take a head torch. I am lucky enough to be able to climb after work and if I set off up a climb with less than a couple of hours daylight left, in it goes.
If possible I try to put it in a pocket but if not, it just clips onto the back. The Petzl eLite, Tikka or Zipka are very popular. A cheaper alternative is the Alpkit Indigo. Whichever you get it, it is worth threading some cord round one of the loops to clip it on as the straps have a tendency to come off.
To cut the tat with. Once you have one you will find a hundred other uses for it. I have the Toerags Penknife which I hold shut with an elastic band. I have replaced the little chain with some cord as it looked a bit fragile. A bit flashier is the Petzl Spatha.
Cheap, light and very effective at getting peoples attention. Try to get one without a pea as those with often don’t work in wet conditions. This and the knife live on a smaller krab, clipped to the main one, which allows me to use the main one with my Prussik loops.
Having this equipment will only save your life if you know what to do with it. Go on a course or get a friend you trust to show you.