mirror of
https://expo.survex.com/repositories/expoweb/.git/
synced 2024-11-22 15:21:55 +00:00
676 lines
39 KiB
HTML
676 lines
39 KiB
HTML
|
|
||
|
|
<html lang="en-US"><head><meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||
|
|
<title>Notes on Alpine-style SRT</title>
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<a name="top"></a>
|
||
|
|
<center><b>
|
||
|
|
<h2>Notes on Alpine-style SRT</h2>
|
||
|
|
</b><p><b><i>from Sherry Mayo's Cave Page</i>
|
||
|
|
</b></p></center>
|
||
|
|
|
||
|
|
<p><i>These notes are the result of three of us here in Canberra teaching
|
||
|
|
other members of NUCC alpine style SRT techniques. More specifically the
|
||
|
|
SRT manoeuvres as described here are the result of me, Mark and John
|
||
|
|
arguing about the best way to do things while our hapless victims
|
||
|
|
were strung up in trees struggling with our SRT obstacle courses - so credit
|
||
|
|
should be given here to all those people (Mark, John and our NUCC guinea pigs).
|
||
|
|
These notes assume a certain amount of fore-knowledge, that you know how to
|
||
|
|
abseil and how to prusik using a frog rig. Please don't try and learn SRT
|
||
|
|
from scratch using these notes, you will just hurt yourself. Get someone who
|
||
|
|
knows to show you how to do it (and if you can't find someone, I'll do my
|
||
|
|
best to give you a contact if you send me email).</i>
|
||
|
|
</p><p><b>Thanks to Nigel Whittington (N.P.Whittington@spps.hull.ac.uk) for
|
||
|
|
helpful input and comments.</b>
|
||
|
|
</p><h2><a name="intro">Introduction</a></h2>
|
||
|
|
<img align="right" width="295" height="505" src="./sherry-mayo/srt-rig.jpg">
|
||
|
|
These are some very short notes to summarise the basic manoeuvres of
|
||
|
|
alpine-style SRT. They are no substitute for practicing the techniques and are
|
||
|
|
intended just as a reminder. If you want more detailed info read a good SRT
|
||
|
|
book such as "Vertical" by Al Warild. <p> The best way to learn SRT is to get
|
||
|
|
lots of practice and get a feel for it rather than trying to learn the moves "by
|
||
|
|
numbers". If you encounter any difficulties underground, familiarity with the
|
||
|
|
basics will get you over them.
|
||
|
|
|
||
|
|
</p><h3>Why Bother?</h3>
|
||
|
|
|
||
|
|
Unlike indestructable rope technique, alpine-style SRT makes use of rebelays and
|
||
|
|
deviations so that the rope hangs freely down the pitch avoiding rub points and
|
||
|
|
other hazards such as waterfalls. This has the advantage that much thinner rope
|
||
|
|
can be used which is much lighter and more compact to carry (or alternatively
|
||
|
|
you can carry much more rope - useful if you are exploring a deep cave).
|
||
|
|
Another plus is that abseiling or prusiking on a free hang is easier than
|
||
|
|
abseiling or prusiking against an uneven wall. The (slight) downside is that
|
||
|
|
you have to learn how to negotiate rebelays & deviations - the techniques and
|
||
|
|
equipment used for these manoeuvres are summarised in these notes.
|
||
|
|
<br clear="right">
|
||
|
|
|
||
|
|
<p></p><hr>
|
||
|
|
<p></p><h2><a name="equip">SRT Equipment for ascending/descending:</a></h2>
|
||
|
|
|
||
|
|
Apart from lots of practice, the thing that will make the most difference to the
|
||
|
|
ease which which you can do SRT manoeuvres is having the right equipment and
|
||
|
|
having it correctly set up and adjusted. Properly set up gear will not only
|
||
|
|
vastly improve the efficiency of prusiking and changeovers, but will also
|
||
|
|
minimise the risk of cock-ups (i.e. getting your gear in a tangle and getting
|
||
|
|
stuck on the rope). The diagrams show the set up of gear for a frog-rig, the
|
||
|
|
most commonly used SRT set-up in alpine caving. IRTers sometimes prefer
|
||
|
|
ropewalking or other types of SRT rig which can sometimes have slight speed
|
||
|
|
advantages on long pitches, but which make it difficult to negotiate rebelays
|
||
|
|
etc.
|
||
|
|
<p></p><center><img alt="SRT equipment" src="./sherry-mayo/srt-fig1a.gif" width="471" height="506"></center><br>
|
||
|
|
|
||
|
|
<i>SRT ascending/descending kit (descender omitted for clarity)</i>
|
||
|
|
|
||
|
|
<h3>The Harness:</h3> this should be a purpose designed caving sit harness. A
|
||
|
|
sit harness is fairly snug fitting and designed so that the central attachment
|
||
|
|
point (i.e. the central maillon to which the chest ascender etc is attached) is
|
||
|
|
fairly low on the body. This is important because the length of a prusik step
|
||
|
|
is determined by the distance between the chest and foot ascender when the foot
|
||
|
|
ascender is raised on the rope. If the chest ascender sits too high on the body
|
||
|
|
this distance is reduced and the caver can only take short prusik steps which is
|
||
|
|
inefficient. Several designs of harness suitable for caving are shown in the
|
||
|
|
diagrams. A climbing harness is also shown for comparison. These can be used
|
||
|
|
for SRT, but are far from ideal because the central loop is too high on the
|
||
|
|
body. Also there is no central maillon and an intermediate krab or maillon has
|
||
|
|
to be used to attach the chest ascender to the harness resulting in it sitting
|
||
|
|
even higher on the body.
|
||
|
|
|
||
|
|
<h3>The chest ascender:</h3> As outlined above, for efficient prusiking the
|
||
|
|
chest ascender must sit fairly low on the body (about on the stomach, just below
|
||
|
|
the sternum). For this reason its is best to use an ascender without a handle,
|
||
|
|
and better still, a purpose-built chest ascender such as the petzl croll which
|
||
|
|
is designed to lie flat on the chest when clipped through the central maillon.
|
||
|
|
|
||
|
|
<h3>The chest harness:</h3> The purpose of the chest harness is to keep the
|
||
|
|
chest ascender in position on the body so it moves cleanly up the rope when the
|
||
|
|
caver stands in the footloops. It also holds the caver in more upright position
|
||
|
|
on the rope which makes prusiking easier. If the harness is too loose, or the
|
||
|
|
chest ascender too high, the caver will tend to lie back of the rope when
|
||
|
|
sitting on the chest ascender, which is both uncomfortable and inefficient for
|
||
|
|
prusiking. The chest harness should be done up sufficiently tightly that it is
|
||
|
|
uncomfortable to stand in when you're not on the rope. Most people use a length
|
||
|
|
of tape with a buckle as a chest harness (see picture). Purpose built chest
|
||
|
|
harnesses are available but don't seem to work any better than the plain tape
|
||
|
|
variety, and don't fit at all if you're female (i.e. if you have a bust). The
|
||
|
|
chest harness isn't intended to be load-bearing and some people use a piece of
|
||
|
|
bungee cord instead of a tape. This doesn't give the caver as much support on
|
||
|
|
the rope but can be better for pulling the croll smoothly up the rope. Some
|
||
|
|
cavers choose to use both a tape and a bungee cord (or similar) and have the
|
||
|
|
best of both worlds.
|
||
|
|
|
||
|
|
<h3>Foot ascender, footloops and safety cord:</h3> The foot ascender can be a
|
||
|
|
handled or standard (non-handled) ascender according to personal preference. It
|
||
|
|
is attached to the caver via a safety cord of dynamic rope (8-9mm is suitable).
|
||
|
|
The cord can either be clipped in directly to the central maillon by the knot in
|
||
|
|
the end, or via an intermediate krab or maillon. There is no hard and fast rule
|
||
|
|
about which is best, it comes down to personal preference. Clipping it in via a
|
||
|
|
krab or maillon means that it can be unclipped from the central maillon while on
|
||
|
|
the rope, however extra ironmongery on the central maillon can also cause
|
||
|
|
problems if you get into a tangle. However, there are definite advantages to
|
||
|
|
attaching the other end of the cord (and also the footloops) to the ascender via
|
||
|
|
a maillon or krab, particularly if you're doing a rope rescue (see rope-rescue
|
||
|
|
section on the pulley-style footloops rig). <p> The foot loops can be made of either
|
||
|
|
tape or rope. Tape tends to be more hardwearing and if a rope is used, the bit
|
||
|
|
that you stand on is best protected by a length of tubing. There is a risk with
|
||
|
|
tape footloops that the tape can get jammed behind the chest ascender cam (this
|
||
|
|
was the cause of an accident in the UK a few years ago), however, many cavers do
|
||
|
|
use tape footloops and this type of incident seems to be rare.
|
||
|
|
</p><p>
|
||
|
|
</p><center><img src="./sherry-mayo/srt-adjust.gif" width="410" height="386"></center>
|
||
|
|
<p>Footloops can either be two separate loops, one for each foot, or a single loop
|
||
|
|
for both feet (as in picture). It is important to get the lengths of the footloops
|
||
|
|
and the safety cord just right. When standing in the footloops (off the rope) lift
|
||
|
|
the foot ascender up till the footloops are taut. If the length is correct the
|
||
|
|
camming part of the foot ascender should be just above the camming part of the chest
|
||
|
|
ascender(see picture). Adjust the safety cord so you can reach
|
||
|
|
the foot ascender when hanging from it on the rope by your safety cord.</p><p>
|
||
|
|
|
||
|
|
</p><h3>Cowstails:</h3> These are a pair of safety cords used for protection during
|
||
|
|
manoeuvres. The long cowstail is used for general security when passing
|
||
|
|
rebelays, deviations and knots. The short
|
||
|
|
cowstail is used specifically for passing rebelays while descending, during
|
||
|
|
which your weight is hanging from the short cowstail alone. Cowstails should be
|
||
|
|
made of 10-11mm dynamic rope with snap krabs clipped through the knot loop at the
|
||
|
|
end of each cowstail (some cavers use 9mm rope in which case fig 9 knots should
|
||
|
|
be used for tying the cowstails). A screwgate krab can be used as an
|
||
|
|
alternative to a snap krab on the long cowstail for extra security while
|
||
|
|
rigging. The krabs can be secured to the knot loops with
|
||
|
|
snoopy loops (loops of tyre inner tube rubber) which hold them in place. <p>
|
||
|
|
The picture shows how the cowstails are tied (there are alternative methods of
|
||
|
|
tying cowstails but this method is the most common one). To tie the cowstails
|
||
|
|
take a piece of dynamic rope about 2.5-3m long, and tie a double figure 8 (or
|
||
|
|
figure 9) knot in one end, tie another double figure 8 (or figure 9) knot as
|
||
|
|
close to the original knot as you can. Then tie a third double figure 8 (or
|
||
|
|
figure 9) knot leaving about about 40 cm of rope between it and the
|
||
|
|
second knot. Swami knots can also be used for the ends of the cowtails - these
|
||
|
|
help hold the krabs in place. Some cavers use overhand knots for the ends of the
|
||
|
|
cowstails as they are less bulky than fig 8's etc, but these do reduce the strength
|
||
|
|
of the rope more than other knots (bear in mind the thickness of the rope you are using).
|
||
|
|
|
||
|
|
</p><p>Make sure all the knots are correctly stacked and then tension the
|
||
|
|
cowstails by hanging your weight from them. The lengths should now be about
|
||
|
|
right. Remove any excess tail rope using a hot knife to seal the ends (the
|
||
|
|
tails needn't be more than 10cm long) and tape the tails of rope to the
|
||
|
|
cowstails. The short cowstail should be about 25-45cm from knot loop to knot
|
||
|
|
loop, and the long one about 50-70cm (it should be at least short enough that
|
||
|
|
you can reach the krab when it's taut). If you clip the cowstails to your
|
||
|
|
central maillon via a krab or maillon you'll want them a bit shorter than if you
|
||
|
|
clip the knot loop into the central maillon directly (see comments about
|
||
|
|
attaching the safety cord above).
|
||
|
|
|
||
|
|
</p><h3>Descenders:</h3> There are many kinds of descenders that can be used for
|
||
|
|
caving but most alpine cavers use bobbins, autolock descenders ("stops"), or racks.
|
||
|
|
The pictures show the way a rack and bobbin are rigged, for abseiling and for locking off
|
||
|
|
(i.e. to lock the descender so it cant move on the rope). The stop works in basically
|
||
|
|
the same way as the bobbin, except it also has a brake lever.
|
||
|
|
|
||
|
|
<p> </p><h4>Racks:</h4>
|
||
|
|
These provide friction by weaving the rope around a series of aluminium (or
|
||
|
|
sometimes steel) bars. Commonly the first (uppermost) and third bars on a rack
|
||
|
|
are fixed, and the second, fourth and fifth bars unclip on one side allowing the
|
||
|
|
rope to be looped behind them. It is possible to "suicide rig" a rack by
|
||
|
|
looping the rope around the wrong side of the bars - this will undo itself as
|
||
|
|
soon as any weight is put on it so always check you've rigged it right!
|
||
|
|
|
||
|
|
<p><img src="./sherry-mayo/srt-rack.gif" width="570" height="308">
|
||
|
|
</p><p>
|
||
|
|
</p><h4>Bobbins:</h4> The rope is wrapped around two fixed wheels to provide friction
|
||
|
|
and then clipped through a braking krab (see picture). One side of the bobbin
|
||
|
|
can be unclipped at the bottom allowing it to be swung open for attaching or
|
||
|
|
detaching the rope. If the rope is very "slow" (i.e. fat and stiff therefore
|
||
|
|
slowing the descent) a bobbin can be "C" rigged with the rope passing around
|
||
|
|
both wheels in a "C" rather than "S" configuration. If the rope is very fast,
|
||
|
|
abseiling with the bobbin on half lock can be used to slow down (see picture).
|
||
|
|
<p>
|
||
|
|
<img alt="rigging a bobbin" src="./sherry-mayo/srt-fig2a.gif" width="575" height="259"><br>
|
||
|
|
<i>Rigging and locking off a bobbin</i>
|
||
|
|
|
||
|
|
</p><h4>Autolock descender ("stop"):</h4> These are a more sophisticated
|
||
|
|
version of a bobbin with a brake lever. When the lever is squeezed you will
|
||
|
|
"go" and when the lever is released you will stop. If you're going too fast
|
||
|
|
remember to let go, it sounds obvious but "it isn't always the most natural
|
||
|
|
reaction" as it says in the Petzl catalogue (people sometimes squeeze the handle
|
||
|
|
thinking it will brake their descent). Some versions of this type of descender
|
||
|
|
are designed to stop when the handle is either squeezed or released and only
|
||
|
|
"go" in the middle position, but these tend to be much bulkier.
|
||
|
|
<p>
|
||
|
|
</p><h4>Other descenders:</h4> Descenders that are often popular with climbers such as Figure
|
||
|
|
8s, or stitch plates are not ideally suited to caving as you have to unclip them
|
||
|
|
completely to get them off the rope (making dropping them more likely on a
|
||
|
|
rebelay). They also tend to twist the rope which is really annoying when you're
|
||
|
|
spinning round on the prusik back out. Whaletails also deserve a mention, if
|
||
|
|
only because of their mysterious popularity with Australian cavers. These are
|
||
|
|
OK for caving, but they are very heavy and bulky (machined out of a solid block
|
||
|
|
of aluminium) and also they are very long which can make otherwise
|
||
|
|
straightforward SRT manoeuvres surprisingly difficult since they take up so much
|
||
|
|
room on the rope.<p>
|
||
|
|
</p><p></p><hr>
|
||
|
|
<p></p><h2><a name="basic">SRT basics</a></h2>
|
||
|
|
<h3>Notes on abseiling</h3>
|
||
|
|
<h4>Controlling speed while abseiling:</h4><p>
|
||
|
|
<img align="right" src="./sherry-mayo/srt-abs.gif" width="152" height="352">Once you have attached your
|
||
|
|
descender to the rope you are ready to
|
||
|
|
abseil. The principle is the same for all descnders - it is the tension of the
|
||
|
|
rope runningthrough the descender that determines your speed. The tension
|
||
|
|
is controlled using the rope <i>below</i> the descender. When abseiling hold the
|
||
|
|
lower rope firmly with one hand down away from the descender. If you hold the
|
||
|
|
rope taut you shouldn't move at all, and to move just let the rope slip slowly
|
||
|
|
through your hand. With a bit of practice you should have no trouble
|
||
|
|
controlling your speed. As well as being able to control speed you also need to
|
||
|
|
know how to lock off a descender so that you can "park" on the rope without
|
||
|
|
needing to hold the rope below you. Methods of locking off a bobbin and a rack
|
||
|
|
are shown in the diagrams</p><p>
|
||
|
|
</p><p>
|
||
|
|
</p><h4>Bottom belaying:</h4>
|
||
|
|
<p>
|
||
|
|
This can be used to provide extra security for novice abseilers. The belayer
|
||
|
|
standso holding the bottom of the rope. If the abseiler gets out of control and
|
||
|
|
starts going too fast the belayer can slow them down (and stop them if need be)
|
||
|
|
by pulling on the rope. This tensions the rope passing through the descender
|
||
|
|
which increases the friction and slows the descent.
|
||
|
|
</p><p>
|
||
|
|
<br clear="right">
|
||
|
|
</p><h3>Prusiking</h3>
|
||
|
|
Prusiking is the method of ascending the rope in SRT. Traditionally this was
|
||
|
|
done using prusik knots which was slow and awkward, but mechanical ascenders
|
||
|
|
have made prusiking much easier. The ascenders have a sprung loaded cam which
|
||
|
|
slides up the rope but not down it. The caver wears a chest ascender attached
|
||
|
|
to the sit-harness and held in place with a chest harness (see picture). A
|
||
|
|
second ascender is attached to the caver via a safety cord. A pair of footloops
|
||
|
|
are attached to this ascender (the foot ascender). The ascenders are put onto
|
||
|
|
the rope by opening the cam, slipping the rope in and letting the cam close on
|
||
|
|
the rope. The cam is usually prevented from opening fully by a safety catch
|
||
|
|
which has to be disengaged for getting the ascender on and off the rope - for
|
||
|
|
any other manoeuvres the safety catch chould be left in place.<p>
|
||
|
|
</p><p>
|
||
|
|
The chest ascender is put on the rope below the foot ascender. The caver sits
|
||
|
|
down on the chest ascender which will be supporting their weight on the rope.
|
||
|
|
The feet are put in the footloops. While sitting on the chest ascender the foot
|
||
|
|
ascender in raised up the rope (you will need to lift your feet at the same
|
||
|
|
time to take the weight off the foot ascender). Then the caver stands up as far
|
||
|
|
as possible in the footloops and the chest ascender slides up the rope. The
|
||
|
|
caver sits back down onto the chest ascender. This sequence is repeated over
|
||
|
|
and over to progress up the rope. The footloops need to be adjusted so that
|
||
|
|
when standing up in them the chest ascender almost meets the foot ascender.</p><p>
|
||
|
|
</p><p>
|
||
|
|
Sometimes the rope won't slide freely through the chest ascender, particularly
|
||
|
|
when you are at the bottom of the rope. With practice you can grip the rope
|
||
|
|
between your feet while standing up in the footloops which will pull it through
|
||
|
|
the chest ascender. When standing up in the footloops, push your feet downwards
|
||
|
|
under your bum rather than out forwards as it makes prusiking easier and more
|
||
|
|
efficient.
|
||
|
|
</p><p></p><center><img src="./sherry-mayo/srt-prus.gif" width="484" height="492"></center>
|
||
|
|
<p>
|
||
|
|
</p><p></p><hr>
|
||
|
|
<p></p><h2><a name="apppi">Approaching pitch-heads</a></h2>
|
||
|
|
|
||
|
|
Pitches rigged for alpine-style SRT will have back-up belays usually a little way back from
|
||
|
|
the pitch-head, with a rope runing from the back-up to the primary belay at the pitch-head.
|
||
|
|
When approaching a pitch-head always clip your long cows-tail into the rope between the
|
||
|
|
back-up and primary belays for safety. Leave it clipped in until you are sitting on your
|
||
|
|
descender on the rope ready to abseil.
|
||
|
|
If the back-up belay is right next to the primary a separate traverse line to the pitch-head
|
||
|
|
should still be rigged for safety .
|
||
|
|
|
||
|
|
<p></p><hr>
|
||
|
|
<p>
|
||
|
|
</p><h2><a name="rebel">Passing Rebelays</a></h2>
|
||
|
|
<img align="right" src="./sherry-mayo/srt-rebelay.jpg" width="349" height="455">
|
||
|
|
A rebelay is where the rope is re-attached (belayed) to the rock part way down a pitch
|
||
|
|
(see picture). If the rope from the top of the pitch meets a rub point/
|
||
|
|
waterfall/loose rock etc. the rope is rebelayed to the rock
|
||
|
|
over to one side so that the lower part of the rope (which hangs down
|
||
|
|
from the rebelay) avoids it.
|
||
|
|
|
||
|
|
<h3>Abseiling:</h3>
|
||
|
|
<ul>
|
||
|
|
<li>Abseil until you are level with the rebelay knot - DON'T abseil past it!
|
||
|
|
</li><li>Clip short cowstail into rebelay (into the knot or the maillon)
|
||
|
|
</li><li>Abseil until your weight is taken by short cowstail
|
||
|
|
</li><li>Take descender off upper rope and put it on lower rope
|
||
|
|
</li><li>Lock descender off (full lock)
|
||
|
|
</li><li>Unclip short cowstail by standing in rebelay loop or on handy ledge to
|
||
|
|
take your weight off it.
|
||
|
|
</li><li>Transfer your weight onto the descender
|
||
|
|
</li><li>Unlock descender and away you go...
|
||
|
|
</li></ul>
|
||
|
|
<b>NOTE:</b> The long cowstail can also be used for extra safety during this manoeuvre:
|
||
|
|
Clip it in initially at the same time as the short cowstail and leave it clipped in for
|
||
|
|
the whole manoeuvre, only unclip it just before abseiling when the descender is half unlocked.
|
||
|
|
This will give you protection should you fail to rig your descender properly.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
</p><h3>Prusiking:</h3>
|
||
|
|
<ul>
|
||
|
|
<li>Prusik up to just below rebelay knot.
|
||
|
|
</li><li>Clip long cowstail into rebelay
|
||
|
|
</li><li>Take weight off chest ascender by standing in footloops
|
||
|
|
</li><li>Transfer chest ascender from lower to upper rope
|
||
|
|
</li><li>Transfer foot ascender from lower to upper rope (watch that the safety cord isn't wrapped round the lower rope)
|
||
|
|
</li><li>Unclip long cowstail from rebelay (you may need to prusik up a little to do this until it is slack)
|
||
|
|
</li></ul>
|
||
|
|
<br clear="right">
|
||
|
|
|
||
|
|
<p></p><hr><p></p><h2><a name="devia">Passing a deviation:</a></h2>
|
||
|
|
<img align="right" src="./sherry-mayo/srt-deviation.jpg" width="336" height="460">
|
||
|
|
A deviation (or redirector) is another means of avoiding rub points and
|
||
|
|
other hazards by altering the hang of the rope down the pitch. The rope runs
|
||
|
|
freely through a krab which is attached to a belay via a tape or rope-loop.
|
||
|
|
This deviation pulls the rope away slightly from its natural vertical hang
|
||
|
|
to move the rope below the deviation away from a rub-point. A deviation
|
||
|
|
never bears the full weight of a caver (only a fraction of it) and
|
||
|
|
consequently deviations can sometimes be used where there isn't a sufficiently
|
||
|
|
strong belay for a rebelay. Since deviations sometimes use poor belays you
|
||
|
|
should never load them with your full weight. In the description below, the
|
||
|
|
cowstail is clipped into the deviation merely to stop you swinging away from
|
||
|
|
it - at no point should you be hanging from the deviation itself, your weight
|
||
|
|
should always be taken by the rope.
|
||
|
|
|
||
|
|
<h3>Abseiling:</h3>
|
||
|
|
<ul>
|
||
|
|
<li>Abseil down to the deviation (you may want to lock off your descender)
|
||
|
|
</li><li>Clip into the deviation with long cowstail
|
||
|
|
</li><li>Unclip deviation karabiner from the rope below you and clip it in on the rope above you
|
||
|
|
</li><li>Unclip cowstail and continue abseiling
|
||
|
|
</li></ul>
|
||
|
|
<p> </p><h3>Prusiking:</h3>
|
||
|
|
<ul>
|
||
|
|
<li>Prusik up to the deviation
|
||
|
|
</li><li>Clip into the deviation with long cowstail
|
||
|
|
</li><li>Unclip deviation karabiner from rope above you and clip it into the rope
|
||
|
|
below you
|
||
|
|
</li><li>Unclip cowstail (you will find that you swing away from the deviation) and continue prusiking </li></ul>
|
||
|
|
<p>
|
||
|
|
<br clear="right">
|
||
|
|
|
||
|
|
</p><p></p><hr>
|
||
|
|
<p></p><h2><a name="chang">Changing from ascending to abseiling:</a></h2>
|
||
|
|
This on its own is not a common manoeuvre underground, but it is the basis
|
||
|
|
of other manoeuvres such as knot passes and it is essential in rope rescue.
|
||
|
|
Being able to change over easily from ascending to abseiling and vice versa
|
||
|
|
is also very useful if you ever have a cock-up (get stuck on the rope) as
|
||
|
|
it will usually enable you to extracate yourself.
|
||
|
|
<ul>
|
||
|
|
<li>Make sure your foot ascender isn't a long way above your chest ascender
|
||
|
|
</li><li>Put your descender on the rope below your ascenders and lock it off
|
||
|
|
</li><li>stand in footloops to unweight chest ascender and unclip chest ascender from rope
|
||
|
|
</li><li>Sit back down until weight is taken by descender
|
||
|
|
</li><li>Unclip foot ascender from the rope
|
||
|
|
</li><li>Unlock descender and abseil
|
||
|
|
</li></ul>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>NOTE:</b> You will find this manoeuvre difficult (or impossible) if you use a
|
||
|
|
long descender such as a whaletail which takes up a lot of space on the rope.
|
||
|
|
It is difficult to rig it far enough up the rope so that your foot ascender
|
||
|
|
safety-cord is slack when you sit back on the descender, particularly if your
|
||
|
|
safety-cord is on the short side. One way around this is to stand in your
|
||
|
|
footloops and clip your short cowstail into your foot ascender. Remove the
|
||
|
|
chest ascender from the rope and sit onto the cowstail. Removing the chest
|
||
|
|
ascender makes more room on the rope for rigging the descender. When the
|
||
|
|
descender is rigged (as high up the rope as possible, just below the foot
|
||
|
|
ascender) stand in the footloops to unclip the short cowstail and sit back down
|
||
|
|
onto the descender. The safety cord should now be slack allowing the foot
|
||
|
|
ascender to be taken off the rope. This "sneaky" method of doing a changeover
|
||
|
|
can't be wholly recommended as you are hanging from a single ascender at one
|
||
|
|
point, which strictly speaking isn't safe. A variant of this technique
|
||
|
|
can also be used for speeding up knot passes (provided you have a short
|
||
|
|
descender!).
|
||
|
|
|
||
|
|
</p><p></p><hr>
|
||
|
|
<p></p><h2><a name="down">Some notes on down-prusiking</a></h2>
|
||
|
|
<img src="./sherry-mayo/srt-downprus.gif" align="right" width="236" height="258">
|
||
|
|
Down-prusiking is used for passing knots when descending, and also used if you
|
||
|
|
need to descend a loaded rope for any reason (i.e. unconscious person on rope
|
||
|
|
below you that needs rescuing). To down-prusik, unweight your chest ascender by
|
||
|
|
standing in your footloops, depress the chest ascender cam from the top to
|
||
|
|
release the rope and slide the ascender down the rope. Release the cam so the
|
||
|
|
chest acender grips the rope and put your weight on it while you move the foot
|
||
|
|
ascender down the rope. Repeat as often as necessary!
|
||
|
|
<p>
|
||
|
|
<br clear="right">
|
||
|
|
|
||
|
|
</p><p></p><hr><p></p><h2><a name="knots">Passing a knot:</a></h2>
|
||
|
|
<img align="right" src="./sherry-mayo/srt-knot.jpg" width="266" height="512">
|
||
|
|
|
||
|
|
You may encounter a knot mid-rope for a number of reasons. Usually it is
|
||
|
|
where two ropes are tied together as a single rope isn't long enough to reach
|
||
|
|
the bottom. You may also encounter a knot
|
||
|
|
where a rebelay has failed or where a damaged section of rope has been
|
||
|
|
tied out.
|
||
|
|
<h3>Abseiling:</h3>
|
||
|
|
<ul>
|
||
|
|
<li>Abseil down to knot
|
||
|
|
</li><li>Clip long cowstail into the loop tied in the tail emerging from the knot (see pic)
|
||
|
|
</li><li>Put foot ascender on the rope a few inches above descender
|
||
|
|
</li><li>Stand in footloops and clip chest ascender into rope between foot ascender and descender
|
||
|
|
</li><li>Take descender off rope
|
||
|
|
</li><li>Down-prusik to knot
|
||
|
|
</li><li>Transfer ascenders (chest ascender first then foot ascender) from above to below the knot
|
||
|
|
</li><li>Put descender on the rope below your ascenders and lock it off
|
||
|
|
</li><li>Unclip long cowstail
|
||
|
|
</li><li>Stand in footloops to unweight chest ascender and unclip chest ascender from the rope
|
||
|
|
</li><li>Sit back down and transfer weight to descender
|
||
|
|
</li><li>Remove foot ascender from rope
|
||
|
|
</li><li>Unlock descender and continue abseiling
|
||
|
|
</li></ul>
|
||
|
|
<b>NOTE:</b> There is a "quick and sneaky" way of passing a knot (while abseiling) that can be
|
||
|
|
used by people with short descenders (and not-too-short safety
|
||
|
|
cords). Abseil onto the knot and put the foot ascender on the rope just
|
||
|
|
above the descender. Clip the long cowstail into the knot-loop for protection.
|
||
|
|
Stand in the footloops, clip the short cowstail
|
||
|
|
into the foot ascender and sit back down on the short cowtail. Take descender
|
||
|
|
off the rope, put it on the rope below the knot and lock it off. Stand in the footloops
|
||
|
|
to unclip the short cowstail, and sit back down (hopefully) onto the descender.
|
||
|
|
Unclip the footloops and long cowstail and abseil. If your descender is too
|
||
|
|
long, or your safety loop is too short you won't be able to do this - it's the kind of
|
||
|
|
thing you should try out in a tree before having a go underground!
|
||
|
|
<p> </p><h3>Prusiking:</h3>
|
||
|
|
<ul>
|
||
|
|
<li>Prusik up to just below the knot (not hard up to the knot)
|
||
|
|
</li><li>Clip long cowstail into the loop tied in the tail emerging from the knot.
|
||
|
|
</li><li>Transfer foot ascender from below to above the knot
|
||
|
|
</li><li>Transfer chest ascender from below to above the knot
|
||
|
|
</li><li>Unclip cowstail and continue prusiking
|
||
|
|
</li></ul>
|
||
|
|
|
||
|
|
<br clear="right">
|
||
|
|
<p></p><hr><p></p><h2><a name="prote">Passing a rope protector</a></h2>
|
||
|
|
<img src="./sherry-mayo/srt-prot2.gif" align="right" width="118" height="138"><img src="./sherry-mayo/srt-prot1.gif" align="right" width="118" height="170">
|
||
|
|
Ideally you shouldn't need rope protectors to rig a pitch, but some rub point are
|
||
|
|
very hard to avoid, and a rope protector can be much simpler than trying to rig
|
||
|
|
the rope around them. To pass a rope protector when abseiling:
|
||
|
|
<ul>
|
||
|
|
<li>Abseil down until you can reach the rope protector knot and lock off your descender -
|
||
|
|
DON'T abseil onto the knot!
|
||
|
|
</li><li>Unfasten the rope protector and untie it from the rope (don't drop it!)
|
||
|
|
</li><li>Abseil to below where the rope protector was tied on and lock off.
|
||
|
|
</li><li>Tie the rope protector back onto the rope above your descender using a prusik knot.
|
||
|
|
</li><li>Fasten up the rope protector as you descend past it, checking that it is correctly positioned.
|
||
|
|
</li></ul>
|
||
|
|
<p> When prusiking the procedure is almost the same:
|
||
|
|
</p><ul>
|
||
|
|
<li>Unfasten the rope protector when you reach it and prusik up to just below the rope protector knot.
|
||
|
|
</li><li>Untie the rope protector
|
||
|
|
</li><li>Prusik up a little
|
||
|
|
</li><li>Retie the rope protector on below you and fasten it around the rope.
|
||
|
|
</li><li>Check the rope protector is positioned properly before carrying on up the pitch.
|
||
|
|
</li></ul>
|
||
|
|
|
||
|
|
<br clear="right">
|
||
|
|
<p></p><hr><p></p><h2><a name="pendu">A note on pendules (or pendulums):</a></h2>
|
||
|
|
<img align="right" src="./sherry-mayo/srt-pendule.jpg" width="286" height="367">
|
||
|
|
|
||
|
|
A pendulum or pendule is basically a variant of a rebelay where the upper and
|
||
|
|
lower ropes are much further apart horizontally (see pic). If abseiling on the
|
||
|
|
upper rope you wont be able to reach over to the rebelay knot to clip in. When
|
||
|
|
level with the knot lock off your descender and pull yourself towards the
|
||
|
|
rebelay using the pendulum loop. Clip in your short cowstail and continue as if
|
||
|
|
you were passing a normal rebelay.
|
||
|
|
<p> If prusiking, start as if passing a normal
|
||
|
|
rebelay (use the pendulum loop to pull in the slack on the upper rope). When
|
||
|
|
your ascenders are on the upper rope you will find your cowstail is taut. Pull
|
||
|
|
yourself towards the rebelay to slacken and unclip your cowstail and then use
|
||
|
|
the pendulum loop to let yourself out across the pitch (otherwise you will go
|
||
|
|
flying across the pitch which is rather unpleasant).
|
||
|
|
</p><p>
|
||
|
|
<img src="./sherry-mayo/srt-pendule2.jpg" width="570" height="310">
|
||
|
|
<br>
|
||
|
|
</p><p></p><hr>
|
||
|
|
<p></p><h2><a name="tyrol">A note on tyroleans:</a></h2>
|
||
|
|
<img src="./sherry-mayo/srt-tyro.gif" align="right" width="200" height="200">
|
||
|
|
This is similar to a pendule in that is is a means of negotiating a rope where
|
||
|
|
there is a significant horizontal distance as well as vertical distance between
|
||
|
|
two belays. A Tyrolean <i>(NB I'm not actually sure if his is the correct name
|
||
|
|
for it)</i> can be rigged much like a pendule (see above) with the
|
||
|
|
addition of a <b>taut</b> rope rigged between the upper and lower belay.
|
||
|
|
To descend, the caver rigs their descender onto the slack (pendule) rope and
|
||
|
|
clips their short cowstail onto the taut rope. The slack rope takes most of
|
||
|
|
the weight of the caver as they descend and the taut rope pulls them over
|
||
|
|
toward the lower belay, so the descent is roughly diagonal.
|
||
|
|
<p>
|
||
|
|
A tyrolean can be rigged as an alternative to a pendule where the large horizontal
|
||
|
|
distance makes it difficult for the caver to pull themselves across the pitch
|
||
|
|
towards the lower belay (see the pendule above). In these cases it is easier to <i>ascend</i> the
|
||
|
|
tyrolean as a conventional pendule without using the taut rope. In other cases a Tyrolean
|
||
|
|
is rigged as a means of pulling the caver away from a hazard such as a waterfall,
|
||
|
|
in which case the caver would clip into the taut rope when ascending as well
|
||
|
|
as when descending. Prusiking up whilst clipped into a taut rope is strenuous
|
||
|
|
but is preferable to being soaked or prusiking up the wall of hanging death etc.
|
||
|
|
<br clear="right">
|
||
|
|
|
||
|
|
</p><hr><p></p><h2><a name="rescu">Rescuing an unconscious caver from a rope</a></h2>
|
||
|
|
|
||
|
|
If a caver is knocked out by a falling rock while on a rope, or becomes
|
||
|
|
unconscious for some other reason, you need to be able to get them off the rope
|
||
|
|
as fast as possible. A person lying unconscious in their SRT harnesses may
|
||
|
|
start to suffocate due to construction of the chest by the chest harness, or
|
||
|
|
possibly due to choking on their tongue. If the casualty is not breathing at
|
||
|
|
all you have 4 minutes to reach them (and you'd have to be bloody fast to figure
|
||
|
|
out what was wrong and get there in time to do anything about it). If the
|
||
|
|
casualty is breathing you have a little longer. The procedure described below
|
||
|
|
assumes you are at the bottom of the pitch, below the casualty. If you are at
|
||
|
|
the top you would have to down-prusik to the casualty, clip their short cowstail
|
||
|
|
into you, and then continue as from step 4. I have also assumed that the
|
||
|
|
casualty was prusiking. If they'd been abseiling they would a) have been using a
|
||
|
|
stop in which case once you reach them, clip into them and use their descender
|
||
|
|
to get down the pitch. b) be stuck in a rebelay loop, in which case the
|
||
|
|
procedure is much the same as if they'd been prusiking, or c) have ended up at
|
||
|
|
the bottom of the pitch.
|
||
|
|
<ul>
|
||
|
|
<li> Prusik up to below the casualty and clip their short cowstail into your central maillon.
|
||
|
|
</li><li> Remove the casualtys foot ascender
|
||
|
|
</li><li> Move your foot ascender and then chest ascender past the casualtys chest ascender onto the rope above the casualty (as if you were passing a knot).
|
||
|
|
</li><li> Continue prusiking until you have taken the weight of the casualty on their short cowstail (which is clipped into you). This is strenuous.
|
||
|
|
</li><li> Remove the casualtys chest ascender from the rope.
|
||
|
|
</li><li> Put your descender on the rope below your chest ascender, and lock it off (full lock off).
|
||
|
|
</li><li> Stand up in your footloops (you'll be taking the weight of the casualty) and remove your
|
||
|
|
chest ascender. This is the difficult part.
|
||
|
|
</li><li> Sit back down onto your descender (your footloops safety cord should be slack when you've sat down).
|
||
|
|
</li><li> Unclip your foot ascender, unlock your descender and abseil to the bottom of the pitch with the casualty.
|
||
|
|
</li></ul>
|
||
|
|
<p> </p><h3>If you can't lift the casualty:</h3>
|
||
|
|
Lifting someone by standing in your footloops isn't easy. If you
|
||
|
|
cant lift them you can re-rig your footloops to give a 2:1 pulley advantage
|
||
|
|
which should enable you to lift almost anyone. To re-rig your footloops, unclip
|
||
|
|
the safety cord and footloops from the foot ascender and tie the footloops to
|
||
|
|
the safety cord. Run the safety cord through a krab (or if you have one, a
|
||
|
|
pulley) which is clipped to the foot ascender (see picture). Now when you stand
|
||
|
|
in the footloops you'll find you are expending less effort in standing up
|
||
|
|
(although you'll only move half as far). You may find the footloops are too long
|
||
|
|
in this arrangement and you'll need to tie out a small section to shorten them.
|
||
|
|
With this re-rig, you effectively have no safety cord between you and your
|
||
|
|
footloops. You could clip in your long cowstail to your foot ascender as a
|
||
|
|
safety cord (otherwise you'll spend a short period during the manoeuvre attached
|
||
|
|
to the rope only by one ascender which is unsafe).
|
||
|
|
|
||
|
|
<h3>If your footloops safety cord is taut when you sit onto your descender:</h3>
|
||
|
|
Conventionally you would stand in your footloops, re-attach your chest ascender,
|
||
|
|
move the foot ascender down a bit and try again (i.e. stand in footloops,
|
||
|
|
remove chest ascender and sit back onto descender). At a pinch (and time is of
|
||
|
|
the essence here) you could just stand in your footloops to slacken the safety
|
||
|
|
cord, unclip the safety cord from the foot ascender and sit down onto the
|
||
|
|
descender, It is possible that you would be unable to recover the foot ascender
|
||
|
|
if you did this, but don't forget you have a spare attached to the casualty.
|
||
|
|
|
||
|
|
<h3>Rebelays:</h3> If possible derig any rebelays/deviations between you and the
|
||
|
|
casualty on your way up. This wont be possible if the pitch has been well
|
||
|
|
travelled, or if you approach the casualty from the top of the pitch. If you do
|
||
|
|
have to pass rebelays on the way back down, treat the casualty as a heavy
|
||
|
|
tackle-bag and proceed as usual. You may need to use your footloops to unweight
|
||
|
|
your short cowstail prior to unclipping it, and re-rigging your footloops as
|
||
|
|
described above would help.
|
||
|
|
|
||
|
|
<h3>Use your brain (& practice lots):</h3> You may not be able to do this
|
||
|
|
manoeuvre exactly as described here, but if you are familiar with the basic
|
||
|
|
techniques and equipment you should be able to work around any difficulties in
|
||
|
|
safety with a bit of cunning.
|
||
|
|
<p></p><hr><p>
|
||
|
|
</p><h2><a name="ropew">Alternative Prusiking techniques</a></h2>
|
||
|
|
It is assumed in most of the sections above that you are using a "Frog rig"
|
||
|
|
for prusiking. This is just one of numerous prusiking rigs, but it is one of
|
||
|
|
the most popular as it is simple and versatile, less prone to "cock-ups" and
|
||
|
|
easy to pass rebelays etc with. Of the alternative prusiking set-ups,
|
||
|
|
"ropewalking" systems are the most popular, especially with US cavers.
|
||
|
|
Ropewalking systems are generally more complex than the frog rig, but they
|
||
|
|
do have a speed advantage provided there are no rebelays or deviations (which
|
||
|
|
is why ropewalking and "indestructable rope technique" are popular with the same
|
||
|
|
people!). Described below are two methods for turning a frog-rig into a
|
||
|
|
rope-walking (or semi-ropewalking) rig.
|
||
|
|
<p>
|
||
|
|
</p><h3>Hybrid Frog-ropewalker</h3>
|
||
|
|
All this requires in addition to the frog-rig in an extra ascender which is
|
||
|
|
attached to the foot firmly with a webbing strap. The other foot still uses the
|
||
|
|
footloops as is the conventional frog-rig. If you use a single footloop
|
||
|
|
rather than a pair, you
|
||
|
|
will probably need to shorten it a little to make it the correct length for use
|
||
|
|
with one foot only.
|
||
|
|
<p>
|
||
|
|
Clip in the chest ascender and footloop foot ascender as usual. Also clip in the
|
||
|
|
ascender attached to the other foot. Instead of ascending by standing up with
|
||
|
|
both feet at the same time progress is made by a walking motion, first lifting the footloops
|
||
|
|
then standing up in the footloops and raising the other foot sliding its ascender up the rope
|
||
|
|
ready for the next step.
|
||
|
|
</p><p>
|
||
|
|
This is a very simple modification to the frog-rig which can give some of the
|
||
|
|
speed advantages of rope-walking, however it is not really a true rope-walking
|
||
|
|
rig.
|
||
|
|
</p><h3>The 'Caving Supplies' Combination rig</h3>
|
||
|
|
<i>Thanks to Nigel Whittington for this description which I've quoted straight
|
||
|
|
from his email.</i>
|
||
|
|
<p>
|
||
|
|
This is a simple modification of the 'Frog' rig that enables
|
||
|
|
energy~efficient ropewalking technique to be used on long pitches and
|
||
|
|
Frog technique to be used on alpine style deviations and rebelays using
|
||
|
|
the same personal rig.
|
||
|
|
</p><p>
|
||
|
|
It uses the standard 'Frog' rig with the addition of an extra
|
||
|
|
jammer, buckled footloop, elastic cord and two carbine hooks. A slight
|
||
|
|
modification to the footloop is also made.
|
||
|
|
</p><p>
|
||
|
|
Make or buy a webbing strap (load bearing!) that will wrap around your
|
||
|
|
ankle and foot in a fig 8 pattern. Use this to fix a non-handled Petzl
|
||
|
|
(tm.) jammer to your LEFT foot.
|
||
|
|
</p><p>
|
||
|
|
Modify the footloop on your top jammer so it can be shortened to about
|
||
|
|
15-20 cm. This can be done several ways, e.g. an extra knot or just
|
||
|
|
clipping the lower loop into the crab or mallion on the jammer.
|
||
|
|
The jammer is attached BELOW the chest jammer and the footloop should be
|
||
|
|
ajusted so that with the right foot raised the janner is just below the
|
||
|
|
chest jammer, with the right foot raised the foot mounted jammer should
|
||
|
|
not foul the floating jammer.
|
||
|
|
</p><p><img align="bottom" alt="SRTpics/srt1.gif" src="./sherry-mayo/srt-srt1.gif" width="193" height="450">
|
||
|
|
<img align="bottom" alt="SRTpics/srt2.gif" src="./sherry-mayo/srt-srt2.gif" width="280" height="452"><br>
|
||
|
|
<i>a) set-up for frog rig with slightly altered footloop<br>
|
||
|
|
b) alteration to footloop and addition of left foot ascender for ropewalking</i>
|
||
|
|
</p><p>
|
||
|
|
Attach an elastic cord to the top of the jammer with a carbine hook, run
|
||
|
|
the cord over your shoulder and attach to the back of your harness via a
|
||
|
|
second carbine hook.
|
||
|
|
</p><p>
|
||
|
|
A crab on the chest harness can be used to clip onto the rope to prevent
|
||
|
|
the possibility of inversion and hanging from ones ankles in the event
|
||
|
|
of the chest jammer accidentally opening.
|
||
|
|
</p><p>
|
||
|
|
<b>USE</b>
|
||
|
|
</p><p>
|
||
|
|
Clip in all three jammers as described, and take short, alternating
|
||
|
|
steps. At the foot of a pitch you may need to weight the rope to ensure
|
||
|
|
the rope runs through the foot jammer.
|
||
|
|
</p><p>
|
||
|
|
<b>To transfer to Frog:</b>
|
||
|
|
</p><p>
|
||
|
|
</p><ul>
|
||
|
|
<li>Disconnect the floating jammer.<br>
|
||
|
|
</li><li>Lengthen footloop.<br>
|
||
|
|
</li><li>Remove elastic cord (optional)<br>
|
||
|
|
</li><li>Connect floating jammer above chest jammer.<br>
|
||
|
|
</li><li>Disconnect foot jammer.<br>
|
||
|
|
</li><li>Feet in footloop.<br>
|
||
|
|
</li></ul>
|
||
|
|
<p>
|
||
|
|
Et Voila, Frog!
|
||
|
|
</p><p>
|
||
|
|
<b>To transfer to ropewalking:</b>
|
||
|
|
</p><p>
|
||
|
|
</p><ul>
|
||
|
|
<li>Connect foot jammer.<br>
|
||
|
|
</li><li>Shorten footloop on top jammer.<br>
|
||
|
|
</li><li>Disconnect top jammer.<br>
|
||
|
|
</li><li>Connect top jammer on rope between foot jammer and chest jammer.<br>
|
||
|
|
</li><li>Pass elastic cord from back of harness, over shoulder and clip to top of
|
||
|
|
what is now the floating jammer (was top jammer).<br>
|
||
|
|
</li><li>Right foot in shortened loop.
|
||
|
|
</li></ul>
|
||
|
|
<p>
|
||
|
|
Et Voila, Ropewalking.
|
||
|
|
</p><p>
|
||
|
|
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
|
||
|
|
|
||
|
|
</body></html>
|