No knots in Amsteel!

[Knotty]

While doing research on whoopie slings I ran into some info posted by Brion Toss on an arborist forum. For those who don't know him, Brion is probably the closest thing to a celebrity in the world of rigging and knots. Highly sought for his expertise.

Brion did testing on Amsteel and other HM (high modulus) lines and said he was never able to get beyond 25% of breaking strength before knots and hitches started to slip and came undone. In many cases it started at 10%. He says the splicing is the only acceptable method when using HM.

Be careful with this stuff.

[MacEntyre]

Do you suppose that applies to things like a towboat hitch? (Similar to the Hennessey knot.)

We used to say that three round turns on a square post would never slip.

- MacEntyre

[Knotty]

I don't know. Here's an excerpt from Brion's comments and a link.http://www.treebuzz.com/forum/showfl...fpart=all&vc=1
"We've done hundreds of break tests in wire, Nylon, Dacron, and assorted high-modulus fibers. And the techies at all the major rope companies have done thousands more. I have yet to see any type of knot -- hitch, loop, bend, anything -- that will reach much over 30% in HM rope, and they almost invariably will slip at as low as 10% unless stoppered or otherwise backed up."

[MacEntyre]

"...unless stoppered or otherwise backed up."

Could that be the key?

- MacEntyre

[vitamaltz]

I've always had stopper hitches on the working end of the bowlines on my 7/64 suspension, but the dang Amsteel is so slippery that I noticed it the bowlines are actually cinching up on themselves. For that reason, I had to add a stopper knot in the loop as well. It takes a lot of planning to get the length of rope right with two extra half hitches.

[Albert Skye]

Here's one of Brion's videos showing a modified bowline slipping.



A multiple (3 or more) fisherman's loop ought to hold if you don't mind jamming, but as has been said many times, knots should be avoided in HM cordage. it makes little sense to use HM rope because of it's high strength-to-weight ratio only to severely reduce that ratio by tying a knot in it.

HMPE (Dyneema/Spectra) fishing line is usually much stronger than its "pound test" rating because it is so vulnerable to knots (much more so than nylon). Naturally, the fishing community is a good source for information about knot strength in HMPE cordage.

[MacEntyre]

Amsteel is so slippery that I noticed it the bowlines are actually cinching up on themselves.

There is almost always a better choice than a bowline... they are notorious for self destructing, but they are so easy!

[animalcontrol]

Now, I need to go back and read the "Whoopie Sling Suspension" thread...
was that part on slicing an eye on pg 28 or 42?
seriously, splice an eye and use the loop as a larkshead?

[Mrprez]

Now, I need to go back and read the "Whoopie Sling Suspension" thread...
was that part on slicing an eye on pg 28 or 42?
seriously, slice an eye and use the loop as a larkshead?

I hope that works, that's how I attached my WS to my hammock!

[animalcontrol]

I hope that works, that's how I attached my WS to my hammock!

you're ahead of me...I tied the dreaded BOWLINE!
and I'm still alive (to the horror of others)