kip wrote:This topic is old as the hills and caves themselves here are some threads if you want to sleep well but the wiki article (link 3) open the PDF is very good but read it well and make sure you understand it before you go running to the hills screaming a new prophecy. We have been doing some testing here in NZ over the last few years with multipoint for rescue and are doing some towards cave applications it supports the obvious but it is too early to release yet.
Thanks for the links! the last one is interesting (I think I understood, don't get the math though )
Two questions:
If you can, can you tell us what's the obvious? I can think that "load sharing is useful and effective but you need to know what your doing" is obvious but that might not be your point...
The second is if as the pdf suggests angle is not so critical (with reason) but leg length, including what is pulled out of the knot is important. Does this support a use where your rescue team or whatever takes in a pre-tied and weighted (pre-tensioned) cordelette (hence limiting the rope coming out of the knot) where all leg lengths are equal, your team then uses spectra etc (as recommended in the pdf) to extend the length of the longer two legs to the desired length giving you close to three (or 4) equal length legs and less variablilty because of reduced slippage out of the knot. It would probably make the rigging quicker too
The obvious downside is that your carrying a length of cord which now only has a specific job reducing the adaptability of your gear, but if required you could undo it assuming you can get it undone that is.
Or another approach: Tie these things out of spectra elimanting the leg stretch and length issue and then your only having to deal with rope or cord pulled out of the knot? But you have no shock absorbing qualities in the cordellete... but if all anchors are taking load there's not going to be any/much shock load right?
Am I missing something here?
It seems the stretch is a double edged sword, it can make up for small errors balancing the load as the loaded leg stretches and pulls out of the knot until load is taken on the other legs but once the stretch runs out the main load will be back on that loaded anchor causing it to fail. Correct?