The most common forms of hauling in caves use a "Z Pulley System"
this can be adapted so that it can contain a progressive capture device
(stop allows two directions of movement eg up and down / jammer allows
one direction of movement eg up) so that the haulers don't have to keep
the tension on the hauling line all the time. Z pulley
systems can be quite compact and can be relatively short in length but capable of hauling long distances, using the minimum amount of rope possible.
Typical pulleys used are Gemini (two pulleys side by side), Tandem (two pulleys in line), Tandem Pro (two pulleys in line but designed to be low in friction), ULTRALEGERE (a pulley wheel which fits onto an oval screw gate, light weight) and Fixe (a single pulley). All of which are made by Petzl and have various advantages and disadvantages.
Other pulleys include those pulleys that capture the rope as it
passes through them, these can be used as a self contained pulley
system or combined into larger system to gain more mechanical
advantage. NOTE IT IS IMPOSSIBLE TO RELEASE THESE UNDER LOAD. These
pulleys include the MINI TRAXION and PRO TRAXION.
There are also more heavy weight pulleys designed for rescue in many
different circumstances, some are made by petzl and other are very
specialist and often built to order, for example one that has six
pulleys on it for use when hauling a casualty up from the middle of a tyrolienne traverse. These include the RESCUE
The most common uses for hauling systems are:-
- Rescue - either hauling a casualty from the ground in a stretcher or harness, or rescuing a person stuck on a pitch.
- Tensioning - They are useful for tensioning ropes for traverses/zip lines.
- Pulling cars out ditches
- Pulling heavy equipment up pitches, eg multiple dive cylinders
- Stretching new rope
- Pulling people up trees and the like and leaving them.
A Basic "z pulley system" in this basic system the "Z" shape the rope makes can be clearly seen. Instead of a tandem a Fixe or a ULTRALEGERE could be used.
This is a more advanced pulley system offering more mechanical advantage but requires more puleys and slightly more rope.
pulley system is essentially the same as the one above but uses two
Gemini pulleys this creates slightly less friction and twisting.
In the above systems the hand jammer can be moved down the rope
being hauled so that thing can be hauled long distances without having
to double/treble/quadruple the rope up over the whole pitch length.
This is an improvised pulley system and could be constructed from
any SRT kit. instead of a prusik loop an other jammer could be used, to
use this type of safety line the casualty needs to be able to move the
jammer / prusik loop.
IF CASUALTIES ARE BEING HAULED THE DEAD MAN PRINCIPLE SHOULD BE
APPLIED. THIS IS THAT THE SYSTEM WILL NOT FAIL IF ANY ONE PERSON/S DIES
OR CAN NO LONGER OPERATE THE SYSTEM. Ideally it is best to be able to
lower as well as raise a victim using a pulley system this allows
easier manoeuvring, a stop is therefore more preferential than a jammer.
It's been proposed we go play in the park to get some examples of systems in operation....
PS..... Wardrobe is an additional extra