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25-Sep-2003 7:48:53 PM
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A question to the forum members:
Why is it recommended that a cordalette be around the 7mm size as opposed to using the diameter of a normal climbing rope? Apart from those who climb with thin ropes - surely a 10 or 11mm rope would be make for a stronger anchor system than a 7mm rope?
Is it mainly a weight consideration - though a cordalette is not all that long?
Cheers,
Bill
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25-Sep-2003 9:19:30 PM
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you need about 8-10m for a good cordelette. if you used 10-11mm rope your going to have to lug it up on your rack somehow. whould be rather large without even thinking about the weight.
obviously 10mm is stronger but if you use spectra then the strength is comparable and size is massively different.
steve
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26-Sep-2003 8:23:35 AM
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You must also remember that when using a cordallette you will be using it doubled so that also increases the overall strength of the setup. When used with 3 pieces of gear the net effect is a very strong and redundant anchor. I`m a big fan of webolettes but I am not a fan of cordalettes tied in the same configuration as a webolette.
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26-Sep-2003 8:57:02 AM
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the other thing to remember is that cordellette is static, which means it can be made of materials such as gemini and spectra. this means you can go down to a diameter like 5 mm and still have a super strong anchor.
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26-Sep-2003 9:29:20 AM
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and further on what Joe said is that climbing rope needs to be thicker to sustain the generally higher forces generated..
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26-Sep-2003 10:11:39 AM
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Fruity, I use spectra, which is super super solid (except it's tolerance to heat), it is not 7mm thick and holds me fine...I haven't followed what your exactly asking....
Does anyone else use spectra for their cordalette ??
Cheers
Chris.
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26-Sep-2003 10:17:24 AM
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yeh i've been using spectra for a few years now and love it.. i reckon it's a lot more friendly than normal cord due to its smaller diameter but similar strength. easy to tie, nice and light.. bit more expensive tho.
I've saw a comparison a while ago on some website which reported i think it was gemini (or maybe someother brand) as falling down in most departments against spectra.. but it was awhile ago now, anyone else seen that?
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26-Sep-2003 1:40:47 PM
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I also use spectra for my cordalette. I read somewhere that spectra has an extremely low friction coefficient which translates to it being able to move around very sharp edges without cutting. It could be described as somewhat soapy as it more or less lubricates itself. My cordalette is a few metres longer than normal and this is an advantage when it comes to building anchors off widely spaced pro. Sometimes I just use it to extend from way back up to a decent tree, I`ll then use another piece or two for redundancy and connect it all together with the rope.
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26-Sep-2003 2:27:15 PM
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I have a Gemini cord version 5.5mm, it is a combination of spectra and kevlar, the advantage being a higher melting point than spectra alone (spectra softens at 100C and melts at 147C). Gemini was made by Black Diamond but is no longer produced. Spectra/Gemini is lighter and more compact than nylon for more strength, but a bloody sight dearer. If you want spectra at the right price try yachting shops, it's about half the price of (us) outdoor retailers!
5.5mm Spectra or Gemini has a breaking strain of about 1800Kg from memory, 7mm accessory cord is about 1000Kg, so doubled we are looking at 3600 and 2000Kg respectively. A 10.5mm climbing rope is about 1800Kg (from memory) so the anchor is stronger, but the strongest cams (larger camalots) are about 16Kn anyway, and a nut or hex only 2 to 12Kn in an ideal (one that can't break) placement, what is the rock rated at anyway? In short they are plenty strong enough and there are more variables than this anyway.
Remember it is critical to use a TRIPLE fishermans knot in spectra because it is slippery...
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26-Sep-2003 2:56:10 PM
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good info dodgy
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26-Sep-2003 2:58:04 PM
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I don't use spectra, mostly because it doesn't flex into the knot shapes that I want as nicely as normal cord does. 8mm is too bulky to carry. 7mm is much nicer. Either way, you'll want to carry 10metres of the stuff. I have 8metres and often find that a little extra length would be mighty useful.
jac
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26-Sep-2003 3:03:47 PM
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I agree with the flex issue Jac but providing you can bash it into a compact bundle to clip onto the back of your harness it's still light and compact. And the yachties have a much wider range of diameters the climbers, I reckon 3mm should still be about as strong as 7mm nylon. Anybody wanna second me?
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26-Sep-2003 3:32:50 PM
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i use 5.5 and have never had any problems with knots jac. my other cordelette is a 7mm cord and i much prefer my spectra.. nad like dodgy says, u just twist it and squeeze it onto a biner on ur harness and it stays like that..
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26-Sep-2003 3:38:38 PM
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I personally prefer the snake cordelette made from webbing, because it doesn't pigtail like cord, is smaller when racked, and with the snake "eyes" rather than a loop, you get more distance for material used. The Australian manufacturer "Vertical" made the one I use the most.
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26-Sep-2003 3:42:57 PM
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I agree with Rich also, I can actually fold mine 4 times over then spin a figure 8 and it's never once fallen out on me and takes under a minute to tie... Very light and very easy to use.... I suppose the thickness of spectra concerned me originally, hwo something so thin can be so strong.... but i'm still here and it hasn't failed me once... hard one to work out when to replace though.....I've had mine for years (2 cords) still looks brand new and i use it everytime i go trad climbing (well almost), How often do you replace yours Rich ?? Dodgy ?? does yours appear to look worn or still very new ??
Cheers
Chris.
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26-Sep-2003 4:29:46 PM
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I replaced one after I towed a car out with it, but I couldn't pick ANY damage...
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26-Sep-2003 5:18:37 PM
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i replaced mine after 3 years use when it decided to learn how to fly off central buttress on a windy day.. it was a bit fuzzier than my new one but still no probs whatsoever
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26-Sep-2003 5:50:27 PM
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HMMM So what your telling me, I need to do something stupid with mine ?? hehehe yeah i've examined it quite closely apart from a couple of flat spots which seem to roll out anyways mine looks fine....they way i tie it anyways, means that a loop doesn't need to be made for it too work, but it's always good to play it safe...
hmmm On another topic (don't know why i thought of this. perhaps the stupid things theme...) but just to give you an idea of how strong a quick draw must be, we loaded up a key ring quick draw (you know the real small ones) We used a sling over a rock, then into the gate then another sling and a steel biner. It took 15 of us clipped into the steel biner, before it bent (not snap!!) the small gate ... buckled. (Just as a matter of interest..) if your bored one night and have allot of alchol and your pritty comfortable with the people around you, then i can highly recomend it... hehehe have a great weekend....
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26-Sep-2003 7:07:59 PM
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Thanks all, some very interesting replies in there indeed.
With respect to the spectra and all the smaller diameter (than normal climbing ropes) which are stronger - would not a smaller diameter rope (irrespective of material) place more stress on the pro? I make that presumption on the assumption that there would be less elongation with these smaller diameter ropes as opposed to a normal rope.
Or am I reading into it too much?
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27-Sep-2003 12:30:48 PM
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anyone use 7mm cord tied as a snake cordellete? would it be strong enough (ok, now that i've read the above, I should ask "is 1000kg strong enough")?
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