That's correct,
To counteract the spin, some folks have found that if you rig the figure
8 for a left exit from the device in the northern hemisphere, the twist
imparted in the rope is neutralized by the Coriolis effect and you won't
spin when ascending the rope. :) LOL
Geary
-----Original Message-----
From: Linda Palit [mailto:[email protected]]
Sent: Thursday, June 11, 2009 9:36 AM
To: Geary Schindel; 'Lyndon Tiu'; [email protected]
Subject: RE: [Texascavers] Figure-8 not proper for caving?
Figure 8's twist the rope. That is bearable for a 20 or 30 foot rope,
but I
ask people not to use figure 8's on my rope if the drop is longer. It
just
creates hassles in coiling and using the rope that seem unnecessary to
me.
I do have several, and they have uses, but not on long drops and seldom
on
drops on my rope --
Linda
-----Original Message-----
From: Geary Schindel [mailto:[email protected]]
Sent: Thursday, June 11, 2009 9:23 AM
To: Lyndon Tiu; [email protected]
Subject: RE: [Texascavers] Figure-8 not proper for caving?
Couple of comments on the Figure 8.
They are suitable for caving as long as you are aware of and willing to
put up with the limitations, much as any rappel device.
Pros
They have no moving parts and can't be easily rigged
incorrectly.
They are relatively cheap in comparison to other devices
They are light
They are compact
They can be easy to drop if you don't know some of the rigging
tricks, as you have to disconnect the device from the harness to attach
to the rope.
Some have ears (rescue 8's), which are bulkier, but all Figure
8's can be locked off.
Commonly used in Youth Programs because they are hard to screw
up, cheap, and simple to use
Relatively durable on CLEAN ropes.
They can be used with single or double ropes
They will accept a wide range of rope sizes
Generally, most folks like to limit their use to drops of less
than 200 feet and I don't like to use them on drops over 100 feet.
Depending upon the drop, you may have to feed rope with longer
drops.
They are a non-variable friction device is that the friction
from the device can't be easily changed with a standard Figure 8. That
is why some of the newer design variants such as the Piranha,
which do allow you to easilt add or subtract friction, are becoming more
popular.
They may be slightly easier to learn on in the sense that you
can't modify friction which is one less factor you have to teach for the
first timer.
Cons,
Big folks may find them fast,
They wear very quickly, as in one rappel, on a dirty rope (read
rat tail file).
If you use them on dirty ropes, you will have to replace them
more often than rappel devices that allow you to change out the friction
surfaces, so for cavers, they may not be economical
They twist the rope, which can make ascending nauseating from
the spin in the rope. It is a misconception that repeated use of a
Figure 8 may damage the rope. There are more rappels done with
a Figure 8 than any other device and probably all devices combined.
There has never been a rope failure caused by a Figure 8. However,
barfing on the rope probably isn't good for it.
There is a risk of dropping the device during changeovers.
Regarding Bill's comment that it may be necessary to obtain more
friction by rapping the rope around the hips, this is not generally
recommended for a couple of reasons. For example, if the user is right
handed, rigged in this fashion, the rope exits the rappel device on the
left side of the person, passes behind the back (hips) of the rappeller,
then reaches the right brake hand, this can present a couple of
problems. If the rappeller let's go of the rope with their right hand,
the rope will fall to the back of the rappeller, they will not be able
to gain control of the rope and will be unable to arrest or control the
rappel. They will probably not be able to recover the rope. Second,
the rope will usually find an indication to ride in around the hips.
This is usually caused by the webbing so you will now have a moving
piece of nylon (the rope) running against a standing piece of nylon (the
harness), which may create severe abrasion and possibly failure. If you
need more friction, use a different device. There are ways to modify
the friction on the device using either a double rap or another
carabineer, but they are beyond this discussion.
When would I use a Figure 8. For short caving drops, especially a long
distance into the cave, for rock climbing, and for canyoneering.
Geary Schindel
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