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I don't know anyone who would still use a double fisherman in canyoneering. It creates dangerous wear/abrasion on the rope and makes it much harder to pull.Quote:
It's been at least 10 years since I've canyoneered or climbed with anyone who used a double fisherman.
Really? :ne_nau:Quote:
I should have said "they" (backcountry rangers) only use double fishermans.
I can introduce you to many who do, I see no validity in your "dangerous wear/abrasion" comment. Can you enlighten me? There would be no more wear than for someone who only uses toss&go at there mid rope point.Quote:
Originally Posted by Scott P
I actually use a square fisherman quite a bit and see no problem with an edk. Saying a certain bend is harder to pull in general makes no sense.
Scott-have you ever made a prusik loop? How did you join the ends?
I've now buggered three ropes because of biner blocks and long pulls across sandstone, but never had the problem with just a knot, including a double fisherman.... your mileage may vary...Quote:
Originally Posted by Scott P
:popcorn:
OBJECTION!Quote:
Originally Posted by oldno7
Knots draw attention to themselves, which sometimes creates extra abrasion on the leading edge of it. Biner block does much the same. The EDK will flip out of the way a lot of the time, thus will avoid this problem sometimes. The EDK is demonstrably EASIER to pull, as it rides over an edge easier, with less effort, and is less likely to get stuck in cracks. Has been tested and shown so by some Aussie guy.
Rappelling double strand with no knot will produce the easiest pull. No knot or biner block to get stuck or attract abrasion. One of the advantages of rigging the rope this way. Use it when it makes sense.
Making a prusik loop is another matter, as there is little desire to have it easy to untie - in fact, much the opposite. A SINGLE fisherman's seems to work fine. Toss it in the washer for a couple cycles to shrink it up well.
Anyway - the thread was about Park Backcountry Ranger protocols. Which to me and other Rich-trained and other not-Rich-trained and other not-officially-trained at all canyoneers throws up a big red flag. YIKES! Somebody determines what tool will work, and then they are supposed to use that one, and that one only? Crazy ==> Dangerous!
Further preaching: long-term safety lies in UNDERSTANDING and good habits, rather than in having protocols and following them. Just as I would never use a tied off square knot, I have no objection to No7 using it - it is a "safe" knot, just not one to my taste. A double-fisherman's? Far from my favorite, and has problems. To me it indicates someone who is "old school", and I usually try to convert them to "new school", ie EDK. :moses:
All indications are that Kaitlen got "taken down the canyon" a couple of times, and that that was the extent of her training. As I have said before, the most dangerous position to be in, is being *A beginner being led by a beginner*. Which was true in this case, she being both the beginner follower and the beginner leader.
Tom
What are you objecting to Tom?
I never said a square fisherman was "the bend of choice" only a good option to know and I do use it just as I also use a grapevine or a Double EDK.
My word was "situational"
ie. I would not want to be hauled up a cliff with 2 ropes joined with an EDK, it would make me even more uncomfortable. On the other hand a double fisherman would work well in that situation. We all know the double fisherman retains greater strength than an EDK and has less tail slippage.
But for simply rappelling you can't "hardly" beat an EDK
Situational I tell ya--situational.
I'm objecting to this:Quote:
Originally Posted by oldno7
IS validity to the dangerous wear/abrasion comment. IS more wear than double-strand, no knot.Quote:
Originally Posted by olnoseven
And let me object to this too:
I don't know that, therefore we don't "all know" it. Greater strength? well, perhaps, although rope-specific tests might be required to "prove" it. In any case, it is a Red Herring as most of us are no longer using manila ropes so simple (and joining) tensile strength is not a significant issue.Quote:
Originally Posted by olNo7
Properly tied EDK has no (zero, nil, naught, cero, nyet!) tail slippage at forces generated in a rappel. Therefore it has the same tail slippage as a double-fisherman's.
"Properly tied" meaning with a backup EDK knot against the primary EDK knot.
Tom
Impressive!!! I like. :five:Quote:
Originally Posted by ratagonia
Quote:
Originally Posted by ratagonia
I object to me not knowing how to do a multi quote.
And I don't know how to fix my mess so I edited it and spaced my comments under Toms.
Manual manipulation...Quote:
Originally Posted by oldno7
start a quotation by putting a
SQUAREBRACKET quote="somebody" CLOSINGSQUAREBRACKET
end a quotation by putting a
SQUAREBRACKET NORMALSLASH quoteCLOSINGSQUAREBRACKET
Tom
[quote="oldno7"]That would be the famous Scott P not the other guy, Scott Card. The less than famous Scott Card trys to stay far away from the engineering, knot strength, friction, mind boggling stuff. :haha:Quote:
Originally Posted by ratagonia
[quote="Scott Card"]I just figured were you liked "objection" you might also be interested in "facts" :haha:Quote:
Originally Posted by oldno7
The abrasion I'm talking about takes place as the rope is pulled down, for instance, when it is pulled across a rounded surface, the part that contacts the rock gets abraded. Making a bend (or a biner block) tends to make a specific place on the rope that gets a lot 'more' abrasion; while a plain rope (no knots) gets abraded evenly across its length.Quote:
Originally Posted by ratagonia
Yeah, that one. Some strange stuff in there. But did clearly demonstrate the EDK pulls better over an edge.Quote:
Originally Posted by CaptainKurt
He used what, for us, would be strange ropes and slings.
I thought we were canyoneering, not climbing.Quote:
Originally Posted by spock's friend
The Fall Factor model is not a good model for short falls, and for when using static ropes. Works well for dynamic ropes longer than a few feet.
Tom
[quote="oldno7"]Nah. Never let facts get in the way of a good story. :lol8:Quote:
Originally Posted by Scott Card
I thought we were canyoneering, not climbing.Quote:
Kurt--o.k. How bout' incorporating a fall factor 2?Or 1 Or 1/2?
The Fall Factor model is not a good model for short falls, and for when using static ropes. Works well for dynamic ropes longer than a few feet.
RATBOY(see--I can play with names to)[/quote]
O.K. So--lets go to what this thread started at-An accident at the last rappel in Pine Cr.
I see at least the potential for 1/2 a fall factor there.
You've never witnessed anyone on rope above an anchor?
That creates potential for a fall factor and potential to load static ropes to dangerous levels. Knowing people wouldn't do this, unknowing would.
So RATfink the potential for fall factors exist's in canyoneering and we don't have ropes to aide in absorbing the shock. Thus all the potential shock is directed at the rapide,anchor, rappeler and yes even the "bends" in the rope or webbing.
This namecalling is so cool ratmess, I wish you would have shown me it sooner :roll:
Sure. You can test it on sharp corner.Quote:
I can introduce you to many who do, I see no validity in your "dangerous wear/abrasion" comment. Can you enlighten me?
The photos in the article pointed out show it well. Usually an overhand knot will flip upword when the rope is pulled rather than drag across the corner. A double fishermans cannot "flip up" and always drags right across the abrasive surface.
Scott
Thanks for the intelligent reply. I see that there is more abrasion that can take place, I understood that. I also understand the general ease of pulling down an EDK,(as I stated I use it alot) I was just more getting to your statement that a double fisherman is not used any more. I believe there is a place and time for there use. THAT'S ALL
There is a reason that the ZNP backcountry rangers will only use a double fisherman to join ropes and I believe it comes down to the link I posted showing greater strength and less slippage over an EDK. I wasn't defending their practice, I cannot generally stand to rappel on 2 strands of 9mm. Especially when wet.
No matter what we have to pull down ropes(if we're not going back up)
So there will always be an abrasion factor on our ropes, I just think the difference in abrasion between an EDK and a double fisherman is minimal. That is not to say that generally an EDK "is" easier to pull down.
o.k. your turn---fire away ratDINK :haha:
Well, looks like you need to work on it a little more, my Dear Kurt --Quote:
Originally Posted by oldno7
also, you might perhaps note that none of my jests on your name have any meanness to them (except, perhaps, if you aspire to act well) - and I suggest for amity's sake, you may wish to adopt the same policy.
But, back to the point...
I am well aware that people can fall while canyoneering. The "Fall Factor" model was developed by climbers to more or less predict the forces generated in a non-ledge-hitting fall - for instance, it does a good job of projecting that while a 90 foot fall on 180 feet of rope may be more exciting, it generates pretty close to the same forces as a 10 foot fall on 20 feet of rope. The model approximates that the length of the dynamic rope is the primary spring and absorber in the system.
For short falls, this is no longer the case, as the flexing of the falling climber, and the tightening of the knots in the system, contribute considerably to the springs and dampers in the system. If the rope is static, even more so. Hence, in canyoneering situations, the Fall Factor model does not really work.
As an example, the Fall Factor model would predict that the forces would be the same for a 2 foot fall on 1 foot of rope, a 4 foot fall on 2 feet of rope, and a 20 foot fall on 10 feet of rope. I can assure you that they are not! While you are likely to barely notice the first, and hurt but survive the second, you most assuredly would not survive the latter, perhaps not even over a deep pool because your back would break before the rope breaks.
And yes, I am trying to inject some rigor into the discussion. You CAN and people DO talk about taking "Fall Factor 2" on a daisy chain or leash; and this confusion with the dynamic rope "Fall Factor" model has led to a lot of unnecessary hand wringing regarding dyneema daisy chains. Although those people who DO canyoneer or climb with 80kgs of steel plates attached to their harnesses SHOULD be concerned.
(pet peeve, can you tell?) :moses:
Tom
All good point's Tom except the name calling thing, that one you missed on.
I believe your attempts were to denote a lack of respect--as were mine.
tit for tat, might be nice to move above and beyond but I'll follow your lead, I'm good either way. :nod:
also might be nice to have an objective debate over tech. issues we both care about, rather than trying to shoot someone down because they're not part of your clique. Maybe we both could learn something. :popcorn:
It's a free country, you are welcome to read into "it" whatever you want.Quote:
Originally Posted by oldno7
My riffing on your name was meant to be a gesture of "lightening up", joviality, playfulness, almost-affection - rather than anything mean or disrespectful.
I thought we were, providing an elucidating technical discussion for the entertainment and enlightenment of Bogley's readers. Again, I suggest that you read too much enmity into my dialogue.Quote:
Originally Posted by oldno7
Tom