... and don't forget about declination and right ascension .. > So there should be no twist issues at the equator? Or do you rig it > to have a forward or front exit at that latitude?... So many nuances > to this issue! > > :) > > On Thu, Jun 11, 2009 at 10:19 AM, Geary > Schindel<[email protected]> wrote: > > 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 > > > > > > > > > > > > -------------------------------------------------------------------- > > - Visit our website: http://texascavers.com To unsubscribe, e-mail: > > [email protected] For additional commands, > > e-mail: [email protected] > > > > > > -------------------------------------------------------------------- > > - Visit our website: http://texascavers.com To unsubscribe, e-mail: > > [email protected] For additional commands, > > e-mail: [email protected] > > > > > > --------------------------------------------------------------------- > Visit our website: http://texascavers.com To unsubscribe, e-mail: > [email protected] For additional commands, > e-mail: [email protected] >
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