expoweb/handbook/rig/exporig.html

105 lines
4.8 KiB
HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>CUCC Expo Rigging Handbook: Expo-specific rigging tricks</title>
<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
</head>
<body>
<h2 id="tophead"> CUCC Expo Rigging Handbook</h2>
<h1>Exotic rigging tricks: pendules, tyroleans, ...</h1>
<p>There are many obscure tricks of rigging that are specific to the case of
exploration, and are rarely used in UK-style SRT.</p>
<h4>Pendules</h4>
<p>A pendule is a technique for crossing a void more or less horizontally. It
can only be rigged if you can get to both ends. The essential idea is to
suspend a length of rope loosely across the pitch, anchored securely at both
ends. To pass it, rig your descender on the rope and descend, as you would a
normal pitch. Once the loop of rope below, going back up to the anchor at the
far end, starts to become tight, attach your jammers to it and pull rope
through until they take your weight; now prusik on this side, pausing to let
out the rope through your descender as needed.</p>
<p>There are a number of pendules <a href="../../fixaid.htm">left rigged</a> in
CUCC's caves, to avoid having to repeat death-defying climbs and traverses that
were originally used to reach the far ends.</p>
<p>Practice above ground suggests that pendules work very badly unless
the hole below is reasonably deep, probably at least half as deep as the length
of the pendule; otherwise you end up prusiking against the force of the tension
in the near-side rope to avoid hitting the deck, which is extremely hard
work.</p>
<h4>Tyrolean traverses</h4>
<!-- This needs work. I haven't actually ever done a tyrolean underground, and
I think it shows! -->
<p>A tyrolean is used in much the same places as a pendule - roughly horizontal
traverses across voids - but is much more difficult to rig, and dangerous if
not rigged right. The idea is to have a tensioned line across, which you can
then run a pulley along.</p>
<p>The risk inherent in this is that of a <i>t-hang</i>, where the tension in
the rope for even relatively light loads becomes enormous. To rig a tyrolean
safely, really massive anchors are needed at each end - big naturals with
backups, or multiple spits - with a completely independent backup line rigged
parallel to the main line (but not under tension). A Z-rig or something similar
can be used to tension the rope.</p>
<p>Tyroleans are also important in rescue rigs, where they can be the only safe
way to transport a stretcher across a traverse; this lies out of the scope of
this guide, and is well covered in <i>Life on a line</i> (available online
somewhere; on Exo there should be a copy in the tatty hut.)</p>
<h4>Rope protectors</h4>
<p>Rope protectors have now all but disappeared from sport caving in the UK,
and I think it is fair to consider them an Expo-specific trick; I have never
used a protector except in Austria.</p>
<p>A protector is essentially a sleeve of tough material that wraps around the
rope with Velcro, and can then be clipped into place with a bulldog clip at the
rub point. They are more or less self-explanatory to use - just remove the
tector when you reach it and replace it once you've passed the rub point; I
include them here because it is easy to forget that they exist. As a general
principle, it's probably not a good idea to use them on trade routes, but they
are ideal for the situation where you just want to descend a pitch quickly to
find out if it goes or not (but don't forget to rerig later if it does go
somewhere significant!)</p>
<p>If you don't have a tector handy, it's often possible to improvise using an
empty tackle sack or dangly bag - you may need to hold it in place until your
weight is across it on the rope, which should then keep it secure.</p>
<hr />
<ul id="links">
<li><a href="../index.htm">Expedition Handbook</a> - Contents
<ul>
<li><a href="index.htm">Rigging Guide</a>
<ul>
<li><a href="intro.htm">Introduction</a></li>
<li><a href="boltplace.html">Choosing bolt locations</a></li>
<li><a href="boltin.htm">The mechanics of placing a bolt</a></li>
<li>Expo-specific rigging tricks</li>
</ul></li>
<li><a href="../look4.htm">Prospecting guide</a></li>
<li><a href="../survey/index.htm">Surveying guide</a></li>
<li><a href="../rescue.htm">Rescue guide</a></li>
<li><a href="../photo.htm">Photography guide</a></li>
</ul></li>
<li><a href="../../infodx.htm">Index to info/topics pages</a></li>
<li><a href="../../indxal.htm">Full Index to area 1623</a>
<ul>
<li><a href="../../areas.htm">Area/subarea descriptions</a></li>
</ul></li>
<li><a href="../../index.htm">Back to Expedition Intro page</a></li>
<li><a href="../../../index.htm">Back to CUCC Home page</a></li>
</ul>
</body>
</html>