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Re: [Perihelion] Most Worthless Piece of Gear:
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jt512
Oct 13, 2010, 4:42 AM
Views: 6340
Registered: Apr 12, 2001
Posts: 21904
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Perihelion wrote: jt512 wrote: If the revolver were frictionless it would increase the force on the belayer by about 50%. Let's say you and your partner each weigh 170 lb. Then, if you used a revolver, it would be like belaying someone who weighed 255 lb. How pleasant an experience would that be? Now, imagine that your partner weighed 200 lb. A 30-lb difference is no big deal, but with a revolver it would theoretically be like belaying someone weighing 300 lb. Is this a reason to be "concerned"? No. Is this a reason to be unhappy? Hell, yes. Jay Even if we ignore friction, your examples would be valid only if we were to climb on perfectly inelastic rope. You are ignoring friction and assuming an inelastic rope, which means that your examples are far removed from reality, so much so that they are useless even as a basis for discussion. The Revolver is not frictionless; it is roughly a 5-10% improvement over a plain biner. (Source: Climbing Self Rescue) This modest reduction of friction, combined with the dynamic properties of the rope, mean that using a Revolver for a TR setup is a non-issue for practical purposes.
What do you mean "even if we ignore friction"? First of all, if we ignore friction, there is nothing to discuss, since the essential difference between the Revolver and ordinary biners is that the former reduces friction. Secondly, my entire conclusion is due to considerations of friction, so we can hardly ignore it. And, no, I'm not ignoring the elasticity of the rope. My conclusions assume that the rope has the same elastic properties regardless of which biner is being used.
As to the improvement in friction being only 5-10%, I'm shocked that it is so small, and frankly, I don't believe it; and, perhaps worse, if your claim is true, I am undecided whether that makes this silly device more or less worthless!
Jay
(This post was edited by jt512 on Oct 13, 2010, 4:50 AM)
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Edit Log:
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Post edited by jt512
() on Oct 13, 2010, 4:49 AM
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Post edited by jt512
() on Oct 13, 2010, 4:50 AM
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