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keinangst
Aug 20, 2004, 5:36 PM
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My granny is a square AND a thieving fisherman.
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ropeburn
Aug 20, 2004, 5:45 PM
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In reply to: My granny is a square AND a thieving fisherman.
:lol:
But the real question is she single?
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paulraphael
Aug 20, 2004, 7:10 PM
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back to the original poster's question (and assuming that a thief knot is a square knot), the thief knot backed up with double fishermans is an excellent knot as far as reliability and ease of untying. I've used this setup for rigging toprope anchors. I would not use it for rap ropes, though, because it makes a huge, bulky package that is begging for trouble. I've had rap ropes get hung up in the mountains, and will do anything possible to avoid it. One easy thing is to use an overhand knot.
as far as the old question, "is the overhand knot safe?" there is no simple yes or no answer. it CAN be safe, but it requires more attention than just about any other climbing knot to guarantee its safety. some guys like to argue that all knots need to be tied properly to be safe, so there's no difference with the overhand, but that's really an oversimplification. if you have two knots that are equally safe when tied well, but one knot is both harder to tie well and loses more strength when tied wrong, then in practice that second knot will be less safe. part of what makes any climbing procedure safe is how easily it can be carried out in bad conditions ... by an exhausted climber, a distracted climber, a climber with cold fingers, in the rain, at night, etc. etc.. there are many circumstances where the tolerances for the overhand knot are unusually critical. The poster who did those informal tests showed us some interesting information, but if you search the web you'll find more scientific tests done on a greater number of rope combinations. The worst cases (certain rope pairings, when wet or frozen) are a bit scary. Some of these knots capsized several times before stabilizing, and did so under pretty low loads.
I've seen enough tests to know that 8" tails are not enough. If the knot does capsize, it will eat up at least 6" of rope when it turns over. And it can turn over again. I tie the knot with 12 to 18 inch tails. Edelrid recommends 45cm, which is on the high end of that.
When it's wet and freezing, and I have a fat rope and a skinny trail line, I consider a different knot. Never a bulky one, but there are some harder to tie options that are compact and assymetrical like the overhand, and which are more stable and also stronger.
In general, mismatched rope diameters are not a problem with the overhand, but in these cases it's even more critical to tie the knot well. This means long tails, no crossed strands, and all four strands pulled tight. it's also nice to have a paranoid partner double checking your handywork. seems like raps happen most often when everyone's tired and more fallible.
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brutusofwyde
Aug 20, 2004, 8:21 PM
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In reply to: In reply to: My granny is a square AND a thieving fisherman. :lol: But the real question is she single?
Well- let's put it this way... she aint hitched... If you want to talk to her, she's currently trolling just off the reef, pulling in little fishies hand over- hand. How many does she need for bait? She figures eight.
Brutus
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fanederhand
Aug 20, 2004, 8:23 PM
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OK, just got off the phone with my local freinds that make some of the best rope (Pigeon Mountain Industries, Inc) and they definitely are agaist using a single overhand. They do slip. One thing they did note on my method (square with fisherman's backup) is that if you tie a granny it will slip. They said that if you use the overhand you have to back it up!!! The agreed that the symetrical square with a fishermans is a good knot jsut tie it right. They also recomend a figure eight with a fishermans on either side to back it up. The 8 is also symetrical. The 8 is easier to tie correlctly. I will try it out.
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robmcc
Aug 20, 2004, 8:29 PM
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In reply to: Then I'll state it the right way for all who care: Granny knot = "granny knot" Square knot = square knot Other than that who the hell cares?
I'm with you on this one. I'm not going to use any of them for climbing, so I'll just have to remain ignorant to the esoteric differences between apparently identical knots.
I do think I have an inkling of how they're different (it's not the body of the knot, it's the ends, right?).
Rob
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cracklover
Aug 20, 2004, 8:52 PM
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To the OP, and those who clarified what the "Thief Knot" is: thanks! I'd never seen that before. Unlike the square w/ a df on each side, which has the problem that dalguard pointed out, the thief knot appears to be so prone to slipping at low loads that it _will_ tighten up against the two df knots. Knot that I'll ever put it to the test! (I couldn't resist getting in on the punning.)
I rappel with the standard (overhand) EDK with nice long tails. For my partners who are nervous about it, I add an additional overhand in one of the tails, snug against the main knot. To my mind, this has all the benefits of the overhand, while mitigating the issue of rolling (or capsizing, I forget which).
GO
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dalguard
Aug 20, 2004, 10:28 PM
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In reply to: OK, just got off the phone with my local freinds that make some of the best rope (Pigeon Mountain Industries, Inc) and they definitely are agaist using a single overhand. They do slip. One thing they did note on my method (square with fisherman's backup) is that if you tie a granny it will slip. They said that if you use the overhand you have to back it up!!! The agreed that the symetrical square with a fishermans is a good knot jsut tie it right. They also recomend a figure eight with a fishermans on either side to back it up. The 8 is also symetrical. The 8 is easier to tie correlctly. I will try it out.
I hope your friends make better ropes than they make judgements. Please make sure you understand what kind of 8 they were recommending. Then, in case they were wrong, please ignore them anyway.
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qwert
Aug 21, 2004, 11:37 AM
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Yes, the overhand definitely is rolling, but whats the problem with that? (it can easily be ignored by just leaving long enough tails)
Have all of you people who are using an 8 year old granny in square configuration backed up with three gay boy scout fishermans or what the hell you are using ever done something else then sportclimbing?
Have you ever had to rappel more than just two or three lengths in not perfect weather?
Have you ever heard about speed= safety?
The overhand is -if tied properly- safe, and also safes lot of time, wich is more likely to safe your but than a 400% übersafe knot, that maybe will never ever under no circumstance become undone, but will get you into trouble since rappeling takes that critical 2 hours to much.
Im shurely not the total alpine superhero or something, but some people maybe should realize that there is a completely different and bigger world beyond there little sporto crags, where they can afford to waste precious minutes on some moronic knots that work only in ideal conditions.
seek qualified advice
qwert
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knudenoggin
Aug 21, 2004, 5:30 PM
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www.scoutxing.com/knots/ashley_bend/ashley_bend.htm
> My question is if I used a thief knot
> in-between the apposing knots of the double fisherman’s
> (effectively sandwiching a thief know between two triple
> stoppers) would I end up dead.
Only if you are highly alergic to knee-jerk reactions
from RC.com (and tell them what you're doing).
> thief knot = "granny" knot
> reef knot = square knot
>
> There is a distint difference.
There is, but you're wrong in the first equality.
Reef = Square (each rope's ends lie together exiting)
Granny ...... (each rope's ends are split, exiting)
Thief = Reef-loaded-*cattycorner*
Grief = Granny-loaded-*cattycorner*
> Bzzzzt. Thank you for playing. You are both wrong. Next contestant.
&
> Still wrong. You seriusly need a good outdoor knots book.
Ah, yes: Clyde's book _Outdoor Knots_ has exactly this reinforced
Thief knot in question photographed (!), though a reinforced "Square
Fisherman's" was intended. Tsk, tsk. (but thanks for playing :o)
(Btw, if you buy this book in six-packs--to gift your knots-dum
climbing buddies, and by the looks of things, there are plenty--,
you can get it from Amazon w/free shipping! Paste a copy of one
of Clyde's posts, and it's almost like (but more legible) having
it autographed!)
> Think how often the backup knot you tie above your F-8
> comes untied. It's the same knot.
!! Really?! "If you can't tie knots, tie lots."
I've often felt that the practice of "leave ends long"
and "always tie a back-up" worked to some degree to
lessen one's attention to tying the main knot well.
It sounds like to some extent that's true; a well
set Strangle knot (what this "half a Grapevine" aka
"Dble.Fisherman's on either side" (misnomer) is)
should not come untied. --begs a question of Why
bother? if it does.
> the halves of the double fisherman's don't tighten
> against each other the way they do unimpeded,
No, not quite; but the point to using the Thief vice Reef
in this instance might in part be that the thus-separated
halves of the Grapevine DO tighten somewhat against the
Thief knot--because that knot slips until the stoppers
impede slippage. So, set the combination knot by abutting
the stoppers to the Thief, and then loading will further
set the structure. But the Strangles will not be so
heavily loaded as they are in a Grapevine, and thus be
pretty easily untied; the Thief then is quite easily
capsized & untied.
> In a book o' knots I have at home their is a "simple simon" knot,
> that I found is easy to untie after loading, and doesn't seem to
> slip at all.
Sounds like one of Harry Asher's fiddlings, and I'd be leary of
this knot enduring much of any rubbing against a rough surface,
re staying tied. I think it's also one that might work less
surely in mixed-nature ropes (7mm + 10.2mm, e.g.). Whereas the
Offset Overhand Bend (cf. that Outdoor Knots book above) works
esp. well in such combination.
For something better & novel, just make half of the EDK a Fig.9.
--knudeNoggin
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knudenoggin
Aug 21, 2004, 6:09 PM
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In reply to: www.scoutxing.com/knots/ashley_bend/ashley_bend.htm For something better & novel, just make half of the EDK a Fig.9.
Ooops, had clipped that Ashley's Bend URL for my own reference. But, FYI,
that's a good knot for various other general purposes, where strength and
easy untying after heavy loading are needed. AND, re this topic, it in fact
is a consequence of one offset bend's ("Rock Mouse") capsizing, giving
assurance on using this (unspecified) novel rap bend (which perhaps will get
to be tested in the not-so-distant future).
As for the "make half of the EDK a Fig.9" direction, let me further that with
reference to Brian-in-SLC's pre-loading image for "Test #3: Frozen Ropes":
given the (too loose) EDK as oriented here, simply remove the RED end
from the final tuck, make a 2nd turn around the load ends of the two ropes,
and THEN tuck the red end out by the yellow; BUT, you should orient this
exit of the red end such that it lies LEFT, not right, of the yellow one. Then
draw up the knot carefully, tightening all parts, and esp. setting the red
rope (which is what's mainly resisting the prying-open forces of the loaded
ends as they enter--and the point of the extra turn is to reinforce this!)
well. This extra turn in the one rope makes its structure a "Fig.9"
(The full Offset Fig.9 was tested long ago by Tom Jones (or Chris Harmstrom)); but making this structure in BOTH ropes actually lessens
the effect of the turn (by spreading it, widening the helix angle). The full
knot worked well, but is needless bulk.)
NB: were this offset bend tied in ropes of different diameters,
the thinner rope should be where the RED rope is--i.e., the one making
the important binding around the loaded ends--; thus oriented, it's more
difficult for it (the thin rope) to be rolled over/around the thicker.
A back-up knot to the EDK can help it, but it also adds bulk. Probably just
setting one overhand knot in the one rope making that initial binding (RED)
would be as good as any
Note that Brian's quick informal tests show surprisingly good behavior of
the EDK, in that he deliberately POORLY TIED his knots! However, under
actual conditions of abseiling, one must consider possible interactions of
the knot and the rock face which could work to deform the knot upon some
movement under load, or maybe in abutting the anchor if the knot is set
against it (possibly by unequal slippage of mismatched ropes through the
rap device). So, such loose knots might fail in other conditions. (Proving
something is so much harder than finding one counterexample! :-)
Brian notes that he'd never actually use such loose knots.
--knudeNoggin
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dalguard
Aug 21, 2004, 9:42 PM
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I've never heard the term strangle knot before. It's certainly a shorter way of saying "half a double fisherman's."
I'm not going to argue this because I'm no knot expert. For rapping, I can't imagine what advantage the boy scout death knot has over an EDK but I'm not going to claim it'll get you killed either. I've used it myself, albeit for joining two ropes for TR, a situation where I wouldn't use an EDK.
Indeed, it was my contribution to an r.c. thread on that subject (joining two ropes for TR) that led to the eventual naming of the BSDK. Check out the thread, this post from Tom Moyer in particular:
http://groups.google.com/...6D13F%40alum.mit.edu
When Tom Moyer and Ken Cline tell me the same thing, I believe them. Mind you, they didn't say it would kill me. They just said they wouldn't do it themselves.
And, yeah, my backup knot comes untied all the time. I don't like a lot of extra rope flopping around. If I tied the tails long enough I suppose it wouldn't, which is also the point Ken and Tom are making re: the BSDK.
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knudenoggin
Aug 24, 2004, 12:58 AM
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In reply to: I've never heard the term strangle knot before. It's certainly a shorter way of saying "half a double fisherman's."
Using a similar form (in mason line or nylon fishline, say 80#) with several wraps
and one extra under-crossing makes a good (end-of-rope) whipping, tied tight
with some help from pliers.
In reply to: For rapping, I can't imagine what advantage the boy scout death knot has over an EDK but I'm not going to claim it'll get you killed either. I've used it myself, albeit for joining two ropes for TR, a situation where I wouldn't use an EDK.
but the Grapevine (and Fig.8 bend), being easily untied after loading. As the Offset Overhand (EDK) has that advantage
as well as quicker tying AND less bulk, the "BSDK" isn't needed the gold medalist.
In reply to: Check out the thread, this post from Tom Moyer in particular: http://groups.google.com/...6D13F%40alum.mit.edu When Tom Moyer and Ken Cline tell me the same thing, I believe them. Mind you, they didn't say it would kill me. They just said they wouldn't do it themselves.
> In a double-fisherman's knot, the tension in the rope pulls the two grapevines together
> and locks them. In the backed-up SQUARE(reef)-knot, the
tension in the rope pulls the
> square-knot tight, but the grapevines [Strangles] don't get tightened.
> If they scrape on the rock and get untied (which
can't happen in the double-fisherman's),
> all you have left is the square-knot. Remember that a guy cratered last
> year in Southern Utah when his square-knot untied. (No, it wasn't backed up.)
The initial query regarded the THIEF knot, not the SquaREef. And, as I noted
previously, the point of using that as the *grapevine separator* is that it lessens,
but doesn't completely stop, the tensioning of the "half-of-grapevine" parts,
the Strangle knots. (One has even LESS of a secure knot were these Strangles to come
untied!) But back to other arguments for preferring the Offset Overhand Bend for
an Abseil-Rope Joining knot (including its accommodation of mis-matched ropes). Let's just not further myths & fears about the competition.
In reply to: >>The grapevine is a pretty reliable safety, >> but not reliable enough for me to bet my life on. And, yeah, my backup knot comes untied all the time. I don't like a lot of extra rope flopping around. If I tied the tails long enough I suppose it wouldn't, which is also the point Ken and Tom are making re: the BSDK.
Didn't seen any Ken komment (btw, what's become of his keen eye for such things?),
but really your back-ups should NOT be coming untied! --the Strangle got
its name for
a reason (tenacious grip, albeit in natural-fiber stuff of the time), and should
hold if set properly. And that shouldn't matter so much about length of tails,
so long as there's adequate purchase to tighten the knot. (And with that THIEF version
of the BSDK, the Strangles should be tightened snug to the Thief.)
--Knots in the Knude
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squish
Aug 24, 2004, 3:06 AM
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In reply to: I'm not going to use any of them for climbing, so I'll just have to remain ignorant to the esoteric differences between apparently identical knots. I do think I have an inkling of how they're different (it's not the body of the knot, it's the ends, right?).
It is the body of the knot. It's not as esoteric as you think. It's so simple that you're missing the forest for the trees.
But I too have a confession to make: I only learned to tie my boots properly just a short time ago. It turns out that all those years I'd been tying my shoelace loops into a granny knot structure instead of the much stronger square. Ever since my Square Knot Enlightenment, my boots no longer come undone.
What's my big secret? Start by tying the bottom half of the knot in the opposite direction (crossing right over left instead of the other way), and you too can be a member of Those Who Know How To Tie Their Shoes.
[This is the part where I contrive some story about how it's saved my life and all climbers need to learn this before it's too late. Then I might conclude with: "Learning the difference between a granny and a square has improved my climbing because my boots now stay on my feet and I don't trip over my laces."]
Seriously, though, take a look at the square knot diagram shown in this thread. With a proper square, the top half is a mirror image of the bottom half. In a granny knot it isn't: one half of the knot goes in the other direction...
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mattrock
Aug 24, 2004, 3:19 AM
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One other way to make it easier to undo knots that have been weighted is to place a carabiner between the strands in the middle of the fisherman knots. of course this could lead to the possibility of your rope getting stuck more than with out the biner, but the knot will untie easier, when youre off rapell.
Matt
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ben87
Aug 25, 2004, 6:15 PM
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Figure 8, properly dressed and set with sufficient tail:
strong, won't fail, easy to tie, not hard to untie afte being weighted, easy to recognize, fairly slim profile (not too likely to get hung up on anything)
seriously I am perplexed by this thread.
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paulraphael
Aug 25, 2004, 6:41 PM
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In reply to: Figure 8, properly dressed and set with sufficient tail: strong, won't fail, easy to tie, not hard to untie afte being weighted, easy to recognize, fairly slim profile (not too likely to get hung up on anything) seriously I am perplexed by this thread.
Well, just to make sure you're not adding to confusion, I'll assume you're talking about a figure-8 tied with the rope strands coming out in opposite directions (like a double fisherman's), NOT with the strands paralel (like an edk). The first way is safe, the second way is not safe.
But even tied the right way, the knot is much more likely to hang up on an edge or a flake than an edk. There's more to the edk than its slim profile. Equally important is its tendency to orient itself away from the rock and away from edges. The 8 does not have this tendency, and it is also bulkier.
With the edk you get a fussier knot in exchange for less chance of hangups.
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paulraphael
Aug 25, 2004, 6:50 PM
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deleted
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rcaret
Aug 25, 2004, 7:06 PM
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Personally I prefer the fisherman's knot :P
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