Nice little knot

[Tree Machine]

That's the right answer. Do you have to untie it (or melt it off) ever?

 

[Stumper]

Yeah, that's right. Isn't there another name for the tautline when it changes direction, other than an open Prusik?

The literature and history are a muddled up mess. It could be called a Midshipman's, Magnus, Rolling or Camel hitch-all of which are depicted both unidirectional and bidirectional in old sailing literature. All of the versions predate Karl Prussik so calling the "corrected Tautline" an open Prussik is inappropriate-no matter how "accepted" it has become on the web forums.Magnus and rolling hitch were the names usually used when tied on a spar-Midshipman's Hitch was the three wrap version on rope. The Camel Hitch descibes the 4 wrap on rope.

 

[Kneejerk Bombas]

Where does "corrected Tautline" come from?

 

[Stumper]

The ultimate authority.---------Me!

Reversing the upper wrap is so much superior to the unidirectional versions that I can only conclude that 3 generations of authors and climbers have just been copying an old mistake.

 

[Tree Machine]

I'm no authority, but I find this stuff fascinating.

 

[CoreyTMorine]

Beer knot and on rope

I'm not real smat, but i do have a book

"On Rope" by Smith and Padgett. They state that the Beer knot/splice was presented by Peter Ludwig from Austria, during an NSS conference. they also say that in 1995 in tests at PMI lab the knot consistently tested at about 80% of the original strength of the webbing.

I generally take anything from "On Rope" with a grain of salt, it is very opininated, and in my opinion, their results are affected by that opinion, theirs, not mine.

 

[CoreyTMorine]

Bull hitch for split tails?

What a great knot! i really like it.

i replace my split tails every month or so. Rather than spend the time or money on splices i use a fishermans. but the single loop does shift / ride up on the biner. I tried an anchor hitch, but didnt like the perpendicular tail.

Will the Bull knot (mr. bull? be secure in an open split tail?

I seize / sew / duct tape the end to the standing part, and climb with a blakes.

 

[CoreyTMorine]

securing a throw bag

Like TM i use little biners, i cut the metal ring right off of the throwbags, then clip the biner through the now vacant hole. However, even before that i used an anchor hitch to tie the slickline to the throwbag. It does not shift on the ring, has never come undone while working and is easily untied. It has worked so well i can't imagine using another knot.

It sounds like other people do use different knots

I'm going to start using the Bull hitch on my little biners but is there a knot that works better than the anchor hitch on a closed ring?

 

[Tree Machine]

Cow, backed with a half-hitch, triple cow, bull, double fisherman's, triple fisherman's, and about twelve others.

To terminate the end of the rope as it exits a hitch or knot ('sieze' the bitter end) you can use an awl to stitch the end and /or whipp it. I only mention the use of an awl because I find it handy for a number of other things in tree care and it's a very inexpensive and versatile tool to have in the kit box with your rope / webbing accessories.

Another use for the bull hitch (along with the Beer knot) is in rigging ascenders. In the most recent instance I tried tying the loops with the ascender handles inside the loop. I like rigging mine with two identical web loops that act as one (no real 'extra weight', nor expense, double the strength and peace of mind). If you were just to apply the loops as I did, the weight of the beer knots would make them drop to the lowest point, which is where you're going to be attaching the ascenders to your saddle, the place where you connect via a caribiner. I feel it necessary to keep the Beer knot out of places of bend, and direct force.

Here's a pic of the Kong duals with dual loop runners. I used a couple stitches with the awl to 'fix' the loops in place and keep the Beer knot from shifting. I set the knots up high, near the handle, in direct line of my sight so I can frequently inspect them in use. The stitch ges through the terminal tail of the beer know, further fixing it from any potential for slippage.

Right now, the loops are just a little bit too long, by maybe 6 or 8 cm (~2-3"). The way I have them rigged, there is no adjustability and not removable (without untying the Beer, or cutting the loop). If I were to attach these same length loops with the bull hitch they'll probably be close to a perfect length, the knot would be secured from shifting, and the loops would be removable. In tying the bull hitch with webbing, dress carefully. With webbing, a girth hitch (aka choker) does not shift much, so the bull twist addition not entirely essential, other than giving the hitch more 'permanence'.

 

[Tom Dunlap]

"On Rope" carries a lot of credibility in the rest of the vertical rope world, opinions and all.

Why would they think of fudging test results that could be easily tested in another lab?

If you want to have a girth hitched sling stay in place better find runners that are sewn with a half-twist in the eye. When the girth hitch is made the result is one that lays flat without twists.

After reading many rope and webbing test results I think that the bull hitch would be weaker than a girth hitch. Is that an issue? It all depends on where the weak link is in the system and what the safety factor of the system is designe to be. I wouldn't want to comprimise the safety factor.

 

[Tree Machine]

Where've you been, Brother? Did you do some out-of-town climbing?

If you want to have a girth hitched sling stay in place better find runners that are sewn with a half-twist in the eye. When the girth hitch is made the result is one that lays flat without twists.

Good one, Tom. One of the finer nuances of slingology.

And true about on-rope. That's one of the definitions of good, objective science; it measures accurately, and is reproducible with other labs. If you're data's not bulletproof, you don't stand to make it in the community.

think that the bull hitch would be weaker than a girth hitch. Is that an issue?

We have to make one assumption, and that is, that the knot is tied properly. If the weak link was not the knot, then the weak link would be the choker/girth/cow-bull, OR the biner. Since our biner is rated at LEAST 25 Kn, we assume the caribiner to not fail. The weak link, by process of elimination, would be the webbing itself, or the hitch. I think the 'practical' difference would be in a severe shockload (rigging) as to where the weak link actually is. A tensiometer would do that. American Wire Rope has those testing units, and you have to pay money and donate your sling to the cause. You can send it and they'll cerify the breaking tensile and tell you exctly where it failed. You could do a couple cows, a couple bulls and have a really good feel for the strength of web slings and biners. Those are pretty massive forces to cause a bull or cow (or tube webbing) to fail.

 

[Tom Dunlap]

IN most cases of soft link testing, they fail at the hitch not the cord/rope/webbing.

 

[Tree Machine]

As we would expect. The hitch is the weak link, which brings us to an important equation that Isaac Newton was working on when he was doing his gravity gig.

<b>If Beer = 80%, then bull =< 80</b>

If a Beer knot will fail at 80% of the rated breaking strength of the webbing, then the bull hitch will fail at somewhere equal to or less than 80%. If we knew the breaking force of webbing, we could extrpolate to figure the breaking strength of cow and bull. We could place bets where we think it might blow out.

Personally, I'd be interested to know the difference in breaking strength between the cow hitch (choker, girth hitch) and the bull. Could be a fun, field trip sort of event. Bring the video camera.

Does this sound like the most direct way to put the dilemma to rest, actually measure it directly?

 

[Tree Machine]

We'd have to set our parameters. Called 'experimental design', laying out exactly what is done and how so that our results would be reproducible.

I'll start the format:

Six slings to be tested, all tied the same length from a 1 meter length of webbing
3 cow, 3 bull
1" (2.54 cm) tube webbing
Cow / Bull affixed to the flat side of a maillon rapide or to the curved inside bend of a steel caribiner (we choose)
Cow/Bull hitches tied at[/i] the testing facility under video
Beer knot placed approximately 50% between the two ends of the sling, right in the middle
testing done under video

Anything else? That way we can share it between ourselves and have it be reproducible.

 

[NickfromWI]

Will the Bull knot (mr. bull? be secure in an open split tail?

Maybe.

And when it comes to rigging, maybe equals NO unless it HAS to equal yes.

love
nick

 

[darkstar]

hey guys im about 10 mins from [on ropes ] shop ... but our local rope manufactuer has better testing equipment ... pidgeon mountain industries .... ill call and request a load test to be done on the ,water / beer ..... only i think they will approve the test already standing .... hey who cares anyhow ...in the real world there are so ,so many other factors ......was thinking when i tie in for rockclimbing i use a figure 8 or a double bowline ... when tree climbing im using a overhand with half hitch b/u ..... go figure .... tree climbing is way more dangerous usually ...i like the overhand because is ties very fast ....always have a long tail ... but then i know im wrong ... :angel:

 

[Tom Dunlap]

If you're going to test the Bull Hitch, you need to start with a webbing sling of known strength. Get a factory sewn one. That'll take the variable of the Beer Knot out of the forumula. We already know how the Beer Knot performs in tubular webbing.

 

[NickfromWI]

That would be AWESOME if the bull hitch could be tested to compare it's strength to the cow hitch.

love
nick

 

[CoreyTMorine]

Cow, backed with a half-hitch, triple cow, bull, double fisherman's, triple fisherman's, and about twelve others.

You think a double fishermans is easier to untie than an anchor hitch? the fishermans has always bound up on me and been difficult to untie. I think we may have a misunderstanding TM. i started using an anchor because it is quick to tie and easy to untie from the closed rings that come with most throwbags.

anyway, back to the subject at hand.

That would be AWESOME if the bull hitch could be tested to compare it's strength to the cow hitch.

love
nick

can we test using 1/2" rope as well?
How much is this going to cost?

re onrope; im not disputing their data, just some of their conclusions. ie "girth hitching as a general rule is unacceptable as a rigging technique" p.65 fig 4-17. and page 115 they state about a figure 8 "unfortunately, this level of control is acheived entirely with the friction against the rappellers hip and the squeezing of the brake hand."

its a good book that i have learned much from reading, but statements like those above are misleading or incorrect, so i take everything from that book with a grain of salt.

 

[Kneejerk Bombas]

That would be AWESOME if the bull hitch could be tested to compare it's strength to the cow hitch.

Take a loop, tie a cow on one end, a bull on the other, and pull. Which breaks first is the loser.