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nickb
Dec 1, 2003, 5:39 AM
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Registered: Jun 24, 2002
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I have an idea for an adjustable shock absorbent anchor system.
I have not tested this and I’m sure it has some issues. But, I thought I would toss it out to web world and take the flaming like a man.
Essentially I thought an anchor could be tied together with two Kong KISA shock absorbers on 9 mm cord. The KISA is a reloadable, thus adjustable length shock absorber device. It is used to absorb static falls on via ferrata and also can be used as a shock absorber on pro. Why not use two of them on separate cords to equalize an anchor? As the anchor is loaded it doesn't matter if the direction of the pull changes the two anchor cords would equalize and absorb the force. KISA’s only weighs 62g. so it’s about the weight of a biner. I would think 9 mm cord should be strong enough when used in pairs and you would only need about 6-7 ft of cord per arm of the anchor, 3 ft to slide and 4 ft to connect to the power point. It shouldn’t be much more trouble than the standard cordellete. I see this kind of thing being used on trad anchors where it might save our sorry behinds from the big plunge. What do you think.
Check out these URL’s : http://www.kong.it/doc408.htm
http://www.kong.it/doc407.htm
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ryanhos
Dec 1, 2003, 7:23 AM
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Not to be a parrot, but you're breaking 2 rules of SRENE.
Equalized. It's only equalized till you fall. After that, who knows how it will be loaded. Furthremore, what happens when one KISA stops at the knot and the other has a couple inches of travel left? Now you're just hanging on one piece. Your complicated, bomber, 2-piece anchor just became a simple, manky, 1-piece anchor.
No Extension. This rule is in place to ensure that if one piece blows, the others aren't shock loaded. Since the KISA is a shock load limiter, this probably isn't much of a concern. However, the extension could have other consequences. At a hanging belay, imagine the power point dropping 3 feet suddenly during a fall. Do you really want your belayer falling 3 feet while trying to catch you?
Lastly, if I read your post correctly, I believe you're speaking of belay anchors and not just running pieces. People generally aren't taking huge whippers on belay anchors. They're top roping. There is no need for shock absorbers.
On top of it all, 2 KISAs in parallel double the "breaking strength." You'd need weaker shock absorbers.
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adeptus
Dec 1, 2003, 11:04 AM
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Registered: Dec 17, 2002
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I have been using the Petzl Zyper, attached to the bottom anchor, for rope soloing trad and aid. In theory it should work, but I haven't tested it by falling.
I think it's a good idea that might save the anchor from getting shock loaded.
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philbox
Moderator
Dec 1, 2003, 9:42 PM
Post #4 of 6
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Registered: Jun 27, 2002
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I like your thinking, I just dunno about the execution though. I reckon a better set up would be to simply build a standard serene anchor and then introduce the Kong Kisa into it so that you are hanging off the Kisa and belaying off yourself. The leader then selects the most bomber piece of the anchor to clip another Kisa into and then clips the lead rope to that. I think that you should be using 10.2mm rope through the Kisas too. I reckon that 9mm is too small.
I`m starting to use Kong Kisas more and more, they are great pieces of kit. I would like to play with them more as screamers on marginal pieces.
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mtnbkrxtrordnair
Dec 2, 2003, 10:18 PM
Post #5 of 6
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Registered: Jun 11, 2003
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If you want a truly absorbent anchor-try Depends :P
edited to add: and they're adjusable too, with the little velcro strips on the sides :o
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nickb
Dec 4, 2003, 5:45 AM
Post #6 of 6
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Registered: Jun 24, 2002
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In reply to: If you want a truly absorbent anchor-try Depends :P edited to add: and they're adjusable too, with the little velcro strips on the sides :o
I assume you have tested this.
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