Re: Experiments with GSP Biminis.


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Posted by Max Garth on 2005-08-07 18:46:21 in reply to Re: Experiments with GSP Biminis. posted by bhorsley on 2005-08-07 17:16:21

Well somebody actually did some tests, 10 years late. Hi George.
The point with Biminis in GsP is that it's got no stretch, and is hellishly slippery, and instead of pulling on the line with the 30 twist knot in it, try putting tension on it and then sliding the knot down the line. Easy as pie.
You can do this with 20 twists, 30 twists and 45 twists using 40lb braid. Over 45 twists it gets harder but it doesn't slip at 70 twists and is rock solid at 100 twists but when you do a pull test on the knot it will break in the knot before it breaks the line.
The other problems with GsP, modulus and diameter in relation to b/s, all come into this equasion because as you increase the load the line does slip a bit and this squeezes the turns which puts pressure on the braid overlaps, which brings that stiffness into play and some fibres get over the critical radius and fracture. This causes the knot to fail.
Biminis have the problem that the main line goes through the twisted section, which is merely a twist with the tag end. All of the tension in on the main line, and as George has explained with mono things happen to suit the knot. GsP isn't mono and with that very low stretch, like 3.6% maximum if you don't get the loop legs even the line doesn't stretch far enough to even things out and one half on the loop does nothing, and the knot really has no useful purpose.
All of which says that biminis suck in GsP 30/50/80 or whatever B/S you use.
Testing the things can be nasty, since most test machines are to IGFA standard and built to accomoddate the stretch in mono, like 30% and the load rate is about 400mm/min
If you use that load rate on GsP because of the low stretch it acts like a shock load and the breaking strain becomes terribly erratic. I know I've tried it on a very special testing machine set to IGFA specs. It needs to be about 100mm/min to be any good at all. Which means modifing the machine. UG.
Best I got was about 90% with a 70 twist bimini and that was with a very slowly poured sand load in a bucket.
All of which pointed me to the coaxial loop system, which is 100% 100% of the time in all b/s braids.
I do not use knots in GsP braids, waste of time, both in tying the things and the fact that, like George pointed out, you need to go to at least 50lb braid to even get 90%.
And thats a very expensive way of doing things. You see the latest batch numbers of Bubonic Braid break a lot higher than the spool says, like 30 is now 48, aka 50, and 50 is now 80 because of the high quality lower denier fibres used in the braid, and the weave and pick rate.. Thats the latest Dyneema for you.
But if you get brave and use CA glue, like LOctite 406 you can use a Uni knot with a loop, and one drop of glue out of the needle applicator. If you are frightened of water use Loctites water proofer.
The glue is a wicking glue and saturates the braid and cures into a solid lump with the little yarns running through it, but locked solidly. Tests at 100% is smaller than a 100 twist Bimini and easier to tie. You only need a very small drop of the glue. Which with a few turn Uni knot id difficult to do without getting the glue wicking into the loop and the standing line.
You can find out this by getting a brochure from DSM HPF in Haarlen Holland. The inventers of the stuff. They say that regardless of who ties knots in GsP or whatever knot it is, it will not get to 100% ever. Some knots get as bad as 48%.
To test the waterproofing of GsP knots I soaked these coax loop things in my swimming pool, chlorinated, for 72 hours and then hung it out in the summer sun under a high brick load for 72 hours. Then I tested it, like perfect. So you can actually hang a fly in a killer whale for three days and it will not fail from the funny GsP stuff.
I haven't tried that, but I figgured it would be OK if you could convince the Orca to eat the fly.
Best of luck chaps, its a bugger of a fishing line, few high sides a million low sides but it works.
Max




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