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| guided rappels |
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Purpose: To
install a tension line that a descender
can clip into in order to rappel laterally
rather than straight down the fall line.
Application: Originally developed
in Europe for bypassing hydraulics or dangerous
water hazards, it is commonly used on the
Colorado Plateau to bypass difficult keeper
potholes or just to avoid some water and
stay dry. It's also a great technique for
moving beginners and injured canyoneers
quickly.
At left: from
the "Never Do This!" file, a canyoneer
who has released the brake strand and grabbed
the guide strand.
Uh, yeah, never do this.
Always keep your brake hand on the rappel
rope and allow your tether to slide along
the guide line. |
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Step 1 - First man
down: This is frequently the crux of
this technique. In the example at right, the
leader is rappeling from an anchor high on
the canyon wall and using balance & friction
to traverse the pothole to set up the guide
line.
Sometime the leader may be able to rig a pilot
guide line with multiple pack
tosses or by throwing knot chocks, or
by lassoing a feature such as a log or protruding
rock surface. As a last resort, the leader
will need to engineer a standard pothole escape.
The leader must understand the geometry of
guided rappels - the anchors will need to
withstand well in exceess of 2x the body weight
of a descender, much more as the guide line
approaches horizontal. |
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If installing a guide line to avoid a water
hazard, you may be able to rig the guide line
by installing a drift
anchor for the leader.
Other methods not covered here include
attempting a plunge or downclimb that bypasses
the hazard. In most cases you shouldn't need
to worry about a pack for the leader as this
can be zip-lined down later, but the leader
should have materials to build an anchor once
safely on the ground below.
Step 2 - Installing the bottom anchor:
On the CP, human anchors are the easiest and
quickest solution. Secure both strands of
line using and eight on a bight or similar
knot and secure it to the top anchor with
a locking biner. Have the leader thread his
belay device or tie off to the pull side of
the rope and place himself in a secure and
braceable position. For the last descender,
unsecure both strands and place a block on
the rappel side of the rope - this allows
the bottom anchor to tension the line - the
descender now rappels off the weight of the
secured bottom anchor, and the rope is pulled
from the rappel side rather than the guide
side. |
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Step 3 - Rappeling
& retrieving the rope: The rappeler
prepares to rappel as normal but also clips
a short (1'-3') tether from their belay loop
to the guide line. As the rappeler descends,
she will be guided by the path of the taut
guide line, hopefully around the obstacle
or hazard. It is very important that both
top & bottom anchors be bomber,
since the forces on the guide line may be
in excess of 5x normal rappeling forces. Failure
of the guideline, especially for the final
descender, can cause serious injury or death.
Especially when using humans for bottom anchors,
always back up your anchors.
Note:
A guide line is NOT a tyrol(l)ean;
a tyrollean is when a rope is stretched horizontally
and anchored at both ends, and is engineered
to support the full weight of the traverser.
Guide lines direct the rappel but do not always
serve as a life saftey line - though if your
guide line fails and the descender swings
20' into the wall, this can be just as fatal.
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| All material © Cerberus
Canyons, LLP 2004-2005 | Disclaimer
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