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Knots: water vs. double fishermans for slings


beefcider

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I keep hearing that that standard knot for tying slings at rap/belay anchors, or slings of any kind always seem to use the water knot as opposed to the double fishermans knot. Is there a greater chance of a DF knot coming untied or do they not work well on slings?

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A double fish is more secure in 5/8 tubular webbing. You don't have to check the knot as often. I also heard that this is the new Outward Bound standard, but I'm not sure it is true. I've switched to the double fish and have had good luck with the small tubular webbing. For the 1 inch webbing I would use the water knot, and check it all the time for security.

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quote:

Originally posted by Crackhead:
A double fish is more secure in 5/8 tubular webbing. You don't have to check the knot as often. I also heard that this is the new Outward Bound standard, but I'm not sure it is true. I've switched to the double fish and have had good luck with the small tubular webbing. For the 1 inch webbing I would use the water knot, and check it all the time for security.

Ditto.

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with webbing you could Try the beer knot; Tie an overhand knot loosely in the middle of your sling or about 14 in. away from one end. then take one end of your webbing and fold it lengthwise then work it inside of the other end. once you have 12-14ish inches inside,work the overhand knot around so it's centered over the stuffed area.tighten the kot securely and check it as you would a water knot. You should have 4-6 inches of tail on each side of your knot. Clean, low bulk, simple.

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The summer 2001 Mountain Bulletin published by the American Mountain Guides Association has a very interesting and somewhat disturbing article about water knots and cyclic loading.

Apparently they did a test on a number of water knots tied in webbing. Generally speaking they attempted to load and unload the knots a hundred times. With a one inch tail they were seldom able to make the hundred count. It pulled through.

So what does this mean?

Webbing tied around trees or other anchors need to be checked. These knots are being presented with cyclic loads. If you do not check the knots prior to rappelling one risks anchor faliure.

The article does not suggest one method over another for tying webbing. However, I have found that water knots work best -- as in they don't come untied -- if they are soaked in water then loaded. This tightens the knot to the point wherein it is unlikely to come untied easily.

The only reason I see that one might not want to use a double fishman's knot in webbing is that it would be quite unwieldy. Tube webbing tied in a water knot lies flat and it is easy to see that it is tied correctly.

Jason

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"The only reason I see that one might not want to use a double fishman's knot in webbing is that it would be quite unwieldy. Tube webbing tied in a water knot lies flat and it is easy to see that it is tied correctly."-Jason

Jason, Try a double fish in 5/8 tubular, it forms a tight cylinder, and you can pull the knot apart easy. I don't think that it is bulkier. Try just changing one of the slings on your rack...to test.I guess that I just feel safer with this knot. I've always heard that the water knot comes undone easy. It is true that you can check a water knot easily though...

It all boils down to preference.

[big Drink][big Drink][big Drink]

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Water knot, beer knot... what about the other drinks? Jagermeister knot, rum knot, 12 year old single malt knot, etc hic.

maybe they can invent a "whine knot" for the crybabies out there. "waah you are rapping on a sling tied with a water knot, we are all going to die, waaaah!"

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quote:

Originally posted by Jason Martin:
The summer 2001 Mountain Bulletin published by the American Mountain Guides Association has a very interesting and somewhat disturbing article about water knots and cyclic loading.

Generally speaking they attempted to load and unload the knots a hundred times. With a one inch tail they were seldom able to make the hundred count. It pulled through.

So what does this mean?

To me, it means they need to re-evaluate their testing protocol. A 1" tail? How realistic is that? If any of you guys only put a 1 inch tail in any kind of knot you trust your life to, remind me to never tie in with you. I bet you repeat that test with 3" tails and the results are vastly different. And, as for me, I tend to evaluate a rap anchor, look at how it's rigged, inspect both the webbing itself and the knot. In my eyes, the water knot is much cleaner, and easier to inspect.

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As long as the tails on your water knot stick out even a tiny bit outside the knot itself.... your rap will be a safe rap.

The cyclic loading caused the tails to slip 0.0028 inches per loading. The water knots did not fail until one of the tails was inside of the knot.

Technically the water knot will fail if loaded and unloaded 1000's of times......

In reality, if there exist tails, you're green for go.

If you're super cheap and prefer bulk webbing for all of your single and double runners and maybe for all of your sport draws as well, the best thing to do is hand stitch 12 times the tails. This casual stitching provides sufficient strength to prevent the 0.0028 inch creep.

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