Pulleys and Knots for Hauling
A pulley or two can be very handy for a vehicle extraction if anchors ARE available, especially solid trees, as a pulley can redirect the towing force if necessary or advisable, to a better direction (eg., downhill), or double the force on the victim vehicle while allowing the use of more rope for stretch, ie., energy storage. Along with each pulley, also include a clevis or chain link to fit its eye, and a sling or short piece of rope for tieing on to an anchor. For slings or ropes, note the following points for how to tie them to avoid losses ‘afterwards’ and make things easier for yourself:
An important consideration in pulling or towing with a rope is how to tie it on: “What would be a good knot to use here?– A Bowline?, yeah! … because it won’t tighten up….” Wrong! — it will tighten, and it does: everyone who has ever pulled someone’s vehicle with a rope has then ended up wasting some of it because a knot couldn’t be untied — except with a knife. If you were lucky in that case, you had a fixed loop of rope over a ball hitch, so at least it could be taken off later without undoing or cutting the knot, and … the next time you need to use the rope for pulling (or being pulled), you may be able to use the same loop again — over a hitch or in a carabiner, quick–link, or clevis.
But in general, you should avoid permanent knots in your towing rope to keep it versatile: you can use more or less of it, and connect it exactly where you want, not just where the permanent loop is, for example. OK, HOW then, to tie on? Well first, never use a knot: because a knot is rope on rope: they bite in to each other and in a sense, become one under high load, ie. very difficult to separate. So tie a rope on to metal, or anything solid that’s strong enough, but still don’t use a knot, but rather a LASHING: the rope goes around the solid ‘hitch’ and back, around itself and reverses back around the hitch to itself, around itself, and back and forth another time or two, then is tied off on the main rope — with a bow tie, etc., it doesn’t matter, as the tow force will be dissipated within a couple of the wraps and never get to the tie-off anyway.
The pictures show that this lashing is like a Munter hitch, then a Super Munter, then possibly an ‘extra-super Munter’, etc. and is finally tied off on the main rope. This can typically be used on a ball hitch, cross bar, ring, carabiner, or slip-hook, etc., and the bigger its diameter the better, to protect the rope at its first wrap around the tie point. After pulling, the tie-off is easily untied, or rather, unwound, and all the lashings come off like magic: no rope wastage.
But, a special case is that of tieing two ropes together, end to end: how can that be done without ending up with impossible knots and rope wastage? This situation isn’t as common, but I have done it to extend a rope so the tow vehicle can get over the crest of a hill in road-towing. In that case, even a sheet bend is no good for linking ropes under high loads. To me the ideal solution would be a metal link with both ropes lashed on to it, and as it happens I do have a solid 4″ iron ring of 5/8″ rod that would work: it has plenty of space for lashing 2 ropes on to it, but otherwise a clevis, carabiner, or even a big chain link would work about as well — maybe even better: a stronger shape, though likely more crowded with rope. Without a metal ring between the ropes, they could be linked with a two- or three-loop bowline in the end of each rope, and hope they can be untied later, though the towing force isn’t likely to be as high in road towing as for an ice-hole extraction, for example.
With the variety of pickles that climbers get themselves in to with their trucks, there’s plenty of room to use your ingenuity, so think over these points and other problems you’ve seen, and throw in a few pieces of gear that you figured out could help, and it likely will, and so avoid needing to be rescued or being unable to help someone else who needs help.