We tested the strength with a simple tug-of-war, with Paul on one end and me on the other. The nylon material used for the test was supposedly rated at 50lb so it should have taken a lot of effort to break it, well certainly a lot on my behalf being a bit ‘muscle limited’. As it transpired the first pair of knots (a Bimini tied in both ends) failed before we even started putting the effort in, just after ‘taking up the strain’. The failure was also clearly in one of the knots, contrary to my previous experience of Bimini twists where the failure almost always occurs in the main line. Quickly dismissed as a ‘one-off’ due to a poor knot, Paul quickly (that was the object of the exercise – to tie quickly), made up another test piece with a loop at either end. Again this proved to be surprisingly weak, I made a mental note that it felt around 10lb to me, with failure occurring in one of the knots once more.
A third test proved to be slightly stronger, but it was still not what I would expect of a 50lb pull and failure once again occurred at a knot. At this point Paul decided that the nylon was crap and handed me the spool after I suggested I could test how much the strength of the nylon had deteriorated, for whatever reason – e.g. UV damage, water absorption etc., by testing it on the Instron.
Well I’ve now done the test – 47lbs UTS! I must caveat that result with the observation that, with the amount of torque generated on the bobbins (that secure the material into the test frame) it was impossible for me to stop them turning and shearing off the anchor points (I could tighten down these anchor points more but that crushes the soft nylon with the same result). As such failure occurred prematurely and the actual UTS figure would be higher i.e. more like the 50lb stated on the spool.
I think the moral of this is that you may be able to tie knots fast but don’t be tempted to, take your time and tie a good knot!
Anyway thanks for the donation of some perfectly good leader material Paul – I’ll put it to good use against some sharks next year.