You know something funny! That image was originally posted by me and those were the trap lines I had/used on my blade. They were built by Trey Brown from Team Velocity Sailing.

WOW atleast give credit where credit is due warbird!

How much do you allow for line creep? If you want the handle X off the deck, how much shorter do you make it to get to X after hanging on it for a few days.
Wouter.
Why do you place a loop at the bottom (after the handle) to attach to the ring or shackle? Why not just the fisherman's knot?

Thanks,
Ken

OOOERR - knots in synthetic line. isn't there some sort of techno law against that?

Why use a splice where a knot is sufficient ?

How does splicing affect strength?

No at all, a splice guarntees 90 to 100% of the breaking load. The breaking load reduction of a knot depends on the rope material. For Dyneema it is said to be around 80% reduction, hence 20% of your breaking load are still usable.

If you have a 500kg breaking load trap line, you can still use 100kg on it, which should be sufficient.

I can't say that I find any justification for these claims in my personal experience.

After a capsize I easily put 100 kg on the line, yet I have never broken one.

Also a splice ONLY get's a high breaking load fraction when ALL parts of the loop are prevented from bending to a radius less then 7 times the line diameter. In effect, if you don't use thimbles in all spliced loops then the wrap around any object will reduced the breaking strength of the spliced loop to much less then 90%.

But we can do numbers on these things as much as we want, fact of the matter is that using knots is sufficient on a 3 mm 500 kg mantle-core dyneema line as proven by myself (90 kg in the nude) overy 7 years now. With me are several others who have done the same to their traplines. The theoretical data needs to be in agreement to that. Having only 20% break strength left doesn't appear to satisfy the real life experience.


Added to this is my cascaded downhaul setup where the later stage is experiencing 300-400 kg load and also using knots to secure it to the blocks. Again, you have good knots (with a high fraction of breaking strength left after knotting) and bad knots. I learned alot when I was still active with stunt kites. Good knots are : Double figure 8 knot, fishermans hitch, sheet bend and the bloodknot. With these you can do everything and not loose more then 50% of the breakstrength in the worst case scenario due to the knot itself.

But my best advice is to learn and remember the "double figure 8 knot" this is truly a good knot. Has the lowest break strength reduction in my opinion, makes very tidy/smooth knot and makes fixed loops. Won't come undone when shook about untensioned like the sheet bend sometimes does.

Wouter