Author Topic: What knot to use as a backup extra savety to hold floating piers (see image)?  (Read 5740 times)

luis peaze

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Inkanyze,
Thanks. My first shot was exactely the anchor bend AboK#1843, I think it is easy yes, but again, easy for whom?

Today, after going over several options annoyed by why and how come they do just go with a bowline, I became attempted to suggest the following options:
1 - a double fisherman?s bend #294;
2 - a double overhand bend #339;
3 - a double hobble knot, for if it holds a crazy donkey, it will certainly hold a pier.

DerekSmith

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Quote
Today, after going over several options annoyed by why and how come they do just go with a bowline, I became attempted to suggest the following options:
1 - a double fisherman?s bend #294;
2 - a double overhand bend #339;
3 - a double hobble knot, for if it holds a crazy donkey, it will certainly hold a pier.

Hi Luis,

The major problem with the cord you are planning to use is that it has a very low self friction.  This means that although it might exhibit a modest friction against some other surface, within a knot, it just slides over itself as if you had smeared the cord with grease.

This means that it really won't matter which knot you choose, because they will all simply slide open when a load is applied.  Even a knot able to incapacitate a donkey driven crazy by brutal humans will be no match for the force of a large wave, amplified by the leverage of the length of the pontoon and delivered into a knot made in one of the slipperiest cords made - it will just slide through itself...

The elements of the solution you will need are - a knot whose strangle grip increases with load, and a stopper which cannot slide open.

The Packers knot has the necessary strangulation property and has the advantage that you can use it to preload the cord before tying off the knot http://notableknotindex.webs.com/butcherknots.html

However, conventional stopper knots will simly pull through themselves.  The normal solution is to use a stopper splice.   Thread the cord back through itself - open up the braid and pass the end of the cord straight through the braid, one side to the other.  Sometimes a solid object such as a round stone is incorporated inside the braid before it is spliced back into the braid.  Then splice the braid back into itself again at the same point, but this time at 90 degrees to the first splice, making a cross splice in the cord... Finally, lock the splice stopper using a liquid penetrating adhesive such as Superglue.

If your cord is ever called upon to do any work, you will find the packers knot drawn tight and hard as steel rope, and the stopper slice jammed rigidly into jaws of the strangling loop

Good luck