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Old 04-06-2011
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Bilgewater Bilgewater is offline
Hmmm
 
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Quote:
Originally Posted by patrickstickler View Post
When one does not have time to make a proper eye splice, common practice is to use a bowline; but, a bowline halves the strength of the line and is thus suboptimal, however convenient.

There is a popular fishing knot, called the duncan loop, which is purported to preserve 95% of the line strength, and I'm wondering if anyone has used, or has any opinions about its use in lieu of a splice, as it can be quickly tied without tools, and can even be used with a thimble to prevent chafe.

The key difference that I can see between a duncan loop and an eye splice or bowline is that the loop will almost surely constrict with use over time, and as such, under significant load it's really more of a bend than a loop, but if a thimble is used, that could be a non-issue.

Though that raises the question of whether a thimble might reduce the strength of the knot, and perhaps a perfectly round thimble might be better than the typical teardrop shape.

Here is one tied with 10mm line:



Given that it is as strong as an eye splice, and can be made more quickly than a splice and without tools, one might wonder why splice at all? Cosmetic arguments aside...
That is the equivalent of a Prusik Knot. We use this at work under extreme loads. We use it for many purposes but quite often it's used as a sacrificial line (sac line) in order to take the weight off the main line. In other words we will tie it on another line which is under extreme load, then release the load and this sac line will take the full weight without slipping. It's a very useful knot but I always put in one more turn (4 in total). Your photo shows 3 turns prior to the half hitch. From experience, that knot if rubbed against a hard edge or corner will definitely cause it to slip and in your case, constrict but with a thimble that wouldn't happen. I would question that without a constant load, the half hitch may just work it's way loose....just a thought.
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