UKC

In reply to jon:
Second from the right is a 10mm galaxy?

In reply to Reach>Talent:

No it's not.

In reply to jon: You should put an epilepsy warning on that.

In reply to jon:

from left to right:

8.5,8.2,9.4,10,8.2,9.5,8.

In reply to jon:

I think the left one is an 8.5mm Mammut one (Galaxy?).

In reply to Taba:

Not bad... a few right there.
And Niallk, a Galaxy is a 10mm.

In reply to jon:
l-r
8.5/8.2/10/9.5/9.2/9.4/8

In reply to jon:

Yeah, couldn't remember what it was called and was being lazy. Genesis was what I was thinking of.

In reply to niallk:
I can see this being a long night!!!!

In reply to liz j:

Again a few right there. But my point is that these ropes are all different generations... If you can't identify the diameters can you possibly say whether an overhand is appropriate or (k)not. Given that they are not what they seem, does it matter?

In reply to jon:
I think that I would happily use an overhand knot on the 8's OR 9's but don't think I would be too happy about mixing the 8's AND 9's. But then what do I know!!!!!

In reply to liz j:

Why? But can you tell which is which?

In reply to jon:
I think the two on the left are the 8's plus the one on the right obviously. The second from left is looks like the red rope though so it is really difficult. Please tell!!!

In reply to jon: But if you had both ropes in your hands you would know roughly what sizes they were.
Also you (or your partner) bought the ropes so you'd certainly have a value for the difference in diameters of your two ropes.

Either way I wouldn't cross anything with more than maybe 5mm diameter difference, figure you're starting to push it after that.

Tom

In reply to pinkpeople53:

But why do you think 5mm defines it. I have to say that I don't know the answer - I was rather hoping something might come of this thread... My view is that as long as ropes are supple, I don't see too much of a problem with any of these. I'm happy to be shouted down - as long as the argument is backed up with logic. I do think, however, that for instance a really stiff old creaky static 11mm and a thin slinky 8mm would be a recipe for disaster - my thoughts being that with the old rope, no matter how hard you pulled, you(d still see daylight through the knot and this would let the thinner rope just slide through. Maybe then a D Fishermans might be better.

In reply to jon:
Are you going to tell us which is which now!!!

In reply to jon:

Mammut Phoenix? (I've got a pair of those.)


No idea...

In reply to pinkpeople53:

But sure it would be much less than 5mm because that's a *huge* difference (like 8 to 13mm)!

In reply to petestack:

Well theres a start. We're actually talking tenths of a millimetre and not millimetres. The difference between an 8mm and a 10mm is only 2mm - or have I drunk too much wine...

In reply to jon: Sorry typo I meant 0.5mm

In reply to jon:

Yep. But perhaps we have to feel that rather than measure it?

So, on similar lines to what I think you're trying to show with your photo, one of my ancient retired 9mm (?) halves looks and feels thicker than my new Mammut Infinity 9.5mm single but the other looks and feels thinner. My new Mammut Phoenix 8.0mm halves are clearly much skinnier than any of these, but you might take my 11mm semi-static for the same diameter as my 10.something wall rope rather than my 11mm Flex...


Yep. But that's really not 'only'...


Not necessarily. But I think the answer to your question lies in feel and judgement rather than tenths of mm!

In reply to jon: 0.5mm difference is arbitrary but with most things in climbing it always boils down to your opinion of 'good enough' I would think there is an increased chance of slipping (or daylight through the knot) with an overhand over this sort of size difference, but again it's entirely what I think.

In reply to jon: I cannot see how 2mm difference will make an overhand knot slip (if that is indeed the concern). I would like to see some testing done on this tho. Any takers?

In reply to jon: This is the best comparison of knots I could find, but still no explaination as to why ropes of different diameters should not be tied by an overhand knot

http://climbing.about.com/od/climbingknots/a/4RapKnots.htm

This page also had some interesting data at the bottom, suggesting that double fishermans weakened the rope least, and so is a more sensible choice for joining ropes

http://www.xmission.com/~tmoyer/testing/EDK.html

Tom

In reply to pinkpeople53:

the difference in rope thickness tends to look alot more than it is if you look end on. It worth bearing in mind when thinking about this that the area of a circle if pi x radius x radius.

I.E. A small difference in the thickness of the rope (twice its radius) makes a much larger difference to the difference of cross sectional area.

In reply to higherclimbingwales:

I'm with you, and will happily use the overhand - except under circumstances I described - but some people aren't. Testing these things, however, often gives a wrong impression as they are always tested to destruction - and any knot will slide through or fuse under these loads. These are loads that, in my opinion, are not likely to occur in a regular climbing situation. These are MY views ONLY. Someone tell me I'm wrong. I don't mind.

In reply to jon:
Are you going to tell us which rope is which now though, before you drink too much of that wine and forget!!!

In reply to liz j:

...what ropes...?

In reply to jon:

Jon, I have to confess to being a double fisherman's dinosaur, on the grounds that I've been using it for a long time and it's never failed yet (and I don't find I have a problem untying it). However (and I might be quite wrong about this) I seem to remember that theoretically the way to join two ropes of very different diameters is by interlocking loops their ends (ie figures of eight or, I suppose, bowlines). I think I might even have done this very occasionally.

What's the 'right' answer from a professional?!

In reply to Dave Garnett:


If it does fail, would you consider changing ?

In reply to jon:

this is as far as i got in 5 mins..

Mammut Genesis 8.5
Beal Ice Line 8.1
Mammut Tusk 9.8
don't know
don't know
don't know - suspect its mammut just under 10 mm
Mammut Phoenix 8.0

In reply to GrahamD:

Good point, although in my experience it's the application of recently-acquired and only half-understood practices under pressure that leads to trouble.

I always use a double fisherman's where the ropes are the same diameter (which is practically always) and I'm aware that I probably shouldn't if they aren't. I know about overhand knots, but that just isn't the way I haitually do it. If in doubt I link things with a krab but, in the very rate situation where I needed to abseil on two ropes of different diameters I think I would probably tie a loop on the end of one with a figure-of-eight and then thread an interlocking loop with a figure-of-eight on the other.

If there's an easy alternative with a clear advantage I would be very happy to adopt it (on the once in a blue moon situation where it's needed).

In reply to jon:

Here are my guesses (I've not read the other answers)

8.5 (mammut genesis)
9.5
10
9.4 (think this looks wider just because the sheath is frayed)
8.2 (looks pretty new)
9.2
8

In reply to Dave Garnett:

On this one, it really does come down to personal choice. Its not like either an overhand or a double fishermans are unsafe. I've happily tied a single and a half rope together with an overhand but I can understand why others might be suspicous.

In reply to liz j:

Genesis 8.5
Legend 8.2
Galaxy 10
Revelation 9.2
Magma 9.4
Infinity 9.5
Phoenix 8

Not all what they seem.

In reply to jon:
Got few right then, this just goes to show that a well used rope can look a lot thicker though, as the revelation looks more like the 10 than 9.2. How was the hangover this morning??

In reply to Dave Garnett:

Hi Dave, no revolutionary opinions other than those I've been implying...

1. Ropes are not always what they seem - the photo is pretty clear.

2. Whilst I accept in theory that ropes of different diameters shouldn't be joined using an overhand, I think this is just trotted out without thinking. The difference between the ropes in the photo (with the exception of the Phoenix) is so miniscule that I would have no hesitation in using an overhand, which is, as far as I'm concerned THE knot for the job.

3. D Fishermans is bombproof, no doubt about that BUT it does get jammed easily.

4. I mentioned somewhere joining a really thick stiff old rope with a new skinny one... here I would do as you have suggested and link two fig eights together, or join them with a krab.

5. The sheet bend is NOT the knot to use in this application, even if it is specifically designed for ropes of different diameters in other applications.

6. I'm always aware of the problems of rapping with two ropes of different diameters and the problem of pulling the thinner one through the belay. To counter this I often rap on just one side, with the knot blocked against the belay. If the belay won't let me do that, then I'll tie knots in the ends and go on two.

In reply to jon:

Why not?
I always use a sheet bend + stoppers for joining a half to a single

In reply to pottsworth:

A sheet bend with stoppers is OK. A sheet bend is not meant to be used *in isolation* as it 'upsets' too easily. In the days of sail the ends were usually seized, but stoppers will work as well.

In reply to pottsworth:

I think you've just missed the whole point of the topic.

In reply to jon:

Please READ the following thread:

www.rockclimbing.com/cgi-bin/forum/gforum.cgi?post=2091962;search_string=Beyond%20the%20EDK;#2091962
(In the Gear Heads sub-forum, thread "Beyond the 'EDK'=>'Offset 9-Oh' et al."

Some good ARJ (abseil-ropes joining) knots are presented in
"Beyond the 'EDK' ...", in which not only are some orientations
of that stoppered Offset Ring Bend (EDK) shown, but also some
alternative knots, of which the Offset 9-Oh is maybe the most resistant
to rolling.

And "leave long ends" should become a gratuitous caution,
given the better knots.

| My view is that as long as ropes are supple,

BINGO!! It's as much flexibility as diameter per se that influences how well
(or not) the knot works. Even with equal diameters, very stiff ropes would make
the Offset Ring Bend ("EDK"/"Overhand"/"Thumb Bend") a dicey proposition.
Still, there are some simple remedies for the basic knot--tying of the one end
with an Overhand around the other (thicker/stiffer) end; making the full turn
with the choking rope (which should be the thinner/flexible one).

| as long as the argument is backed up with logic

Indeed; mostly what you see are echoes of nonsense--if enough people say
it, it must be true, right?! (no)

| with the old rope, no matter how hard you pulled, you'd still see daylight through
| the knot and this would let the thinner rope just slide through.

Good thinking; which is why you orient the different ropes so that it would
be the THICK rope that would have to pull through (or which the thinner
rope would have to be pried out around). And why you might employ the
other precautions presented in the RC.com thread (which was referred
to this forum not all so long ago--but, gee, how quickly we forget, or
ignore, or don't Search for...).


And what a sorry lot that is, eh? The Fig.8 (Flemish) Bend should NOT be
called "Fig.8 Fisherman's": that moniker fits the knot that is a pull-together
one, like the venerable (single) Fisherman's knot, but with Fig.8 components
vice Overhands. And that knot has nothing special to recommend for the
purpose of abseil-ropes joining. Ideally, the ARJ knot should be **offset**,
so that the hauled line will run smoothly over rough surfaces; it should be
quick & easy to tie, as bail-outs with threatening weather or with fatigue
after a long day up the wall don't lend themselves to recalling clever details;
and it shouldn't be hard to untie (though rap loads shouldn't over-tighten a knot).

Note how sloppily tied both the Fig.8 bend and one of the Strangle ("half a
Dbl.Fish.") knots are?! FORGET THAT PAGE'S RECOMMENDATION

Now--or later--, to go chase down the nonsense referred to by
the OP, to plant a silver stake in it lest another echo rise ... .

*kN*

ps: The sheet bend is not "specifically designed for ropes of different diameters" ;
it originated (as best I can tell) for tying line to a clew, a sort of ring in a sail.
LIKE the Offset Ring Bend, it is Asymmetric, and thus if one's ropes are also
*asymmetric* (so to speak), one might think that the knot will lend itself to
joining them; and, within reason, it works fairly well at that, but in climbing
materials can slip (and in equal diameters--cf. www.caves.org/section/vertical/nh/50/knotrope.html ).

I
More re that nonsense site cited above re ARJ knots:
it asserts:
" Do not use this knot with ropes of varying diameters,
since at least one fatal accident has occurred from it coming untied.
Alternatively you can tie a double figure-8 knot instead of the
overhand knot, although testing at Black Diamond’s lab in Salt Lake City
indicates that the double overhand is stronger than the double figure-8. "

Now, I know of no documented case of a fatality from the Offset Ring Bend;
but there was a well-known case of the Offset Fig.8 bend coming untied
on the descent of two Brits in Zion Nat. Park USA about 8 years ago
(which I think Tom Moyer cites at www.xmission.com/~tmoyer...).
SO, above, we see exactly how reliable this other WWWeb site is
--suggesting the bad knot vice the good! And then this rubbish
gets echoed, perhaps?

)-:

In reply to knudeNoggin:

I thought this had died and was about to pull the photo of the ropes. Firstly I remember your thread of a few months ago. Secondly, sorry, I don't understand what you've written above, as it appears to be in another language.

In reply to knudeNoggin:

Why type the pipe when it's no more effort to type the RH angle bracket/greater-than sign to get your quotes both automatically 'quoted' and distinguishable?

| This is not easily distinguishable from the surrounding text.

In reply to petestack:

I agree Pete, but I can't tell if he's saying that I'm talking bollocks or agreeing with me!

In reply to jon:

Neither can I, but knowing who said what *might* be a start!

In reply to jon: I couldn't work out what he was saying either but followed one of the links in the text and found this. http://www.bdel.com/scene/beta/qc_kp_archive.php#123008

A quick summary:
It tests the double fishermans, ring bend (water knot) and Euro death knot (overhand) with 2x 10.2mm ropes, 1x 10.2mm and 1x 8.1mm and 2x 8.1mm. All knots and rope combinations failed at loads that are much higher than needed, although the overhand is 20-30% weaker than the other two knots it's still more than strong enough.

In reply to Kane:

I rest my case then. The overhand is fine with different diameters - 10.2 + 8.1.

In reply to jon:


You can ask better questions than just remark like this.
I wrote, of course, in English. Granted, it was longer than a tweet.

As for agreeing with YOU, rather, I was taking strong issue with the advice
you quoted from someone else. You wondered how "different" diameters
had to be to fall under that bad advice; I counter that the advice is bad,
and you needn't focus so much on diameter per se vs. qualities of flexibility.
For the most part of climbing lines joined to haul lines, the Offset Ring Bend
(ORB), which is also called --unfortunately-- "Overhand <whatever>",
should work fine, IF one takes care to orient the knot so that the thinner
line is what makes the *choke* around the main lines entering the knot
--which aspect is best illustrated graphically, and hence the URLink to
photos: the orange (8mm) line is this line in those photos, tied to 11mm
rope.

Re '|' vs. '>', I chose the former when shifting from the named person's
text to another's (or where I'm quoting something from another source).
Didn't realize the benefits of presentation got with '>', which, yes, is easy.
Thanks,

*kN*

In reply to knudeNoggin:

Sorry, still didn't quite get it. But I didn't quote someone else.

In reply to Kane:

Then point to what is unclear to you and ask; I can re-phrase,
or maybe provide a link.

>www.bdel.com/scene/beta/qc_kp_archive.php#123008

Two important points here:

1) we see one sample knot implying how the Ring bend was loaded
(i.e., on which of the two parallel/traced ends load was applied, the
other being the tail)--which might affect strength (which is of
no importance here, re rappelling)--;

2) we don't know how the ORB* was oriented for mixed diameters:
i.e., was the 10mm rope making the choke, to be pried out around the 8mm,
or the other way 'round--that makes a difference on stability!
Which is why I showed the mismatched combination in the photo.
(*nomenclature: the Ring Bend loaded in an *offset* orientation
(which many knots can be--e.g., there is on-line testing of the Dbl.Fish.
so loaded, a Bachmann idea, tested by Edelrid)).

Strength testing for a abseil-ropes-joining knot is a bit beside the point,
which is SECURITY, and which is better checked under rap-like loading
--light and variable. (Consider that the slippage of some tapes in the
Water knot is seen not at slow-pull-to-rupture testing (it holds & breaks)
but at cyclical low loading, where the exterior tail is ratcheted into the knot.)
So, this testing can give some assurances, but leaves open some questions.

You might want to try to understand what I've said, rather than grouse
about it to each other.

*kN*

In reply to jon:

Okay, not "quote" in the sense of ">" or exact wording; but in the sense
of referral--to wit:
>
>A(nother) recent topic about tying different diameter ropes together

Here is a necessary point: like the Sheet bend, unlike the Ring Bend (Water knot),
the Offset Ring Bend (RB loaded on parallel ends on one/same side) is
asymmetric, and potentially well suited to ropes that are unequal.

Now, when someone says that "the Sheet bend was designed for ropes of
different diameters," they point to a common recommendation for its use
in such situations--AND WITH the assumed (and usually specified) orientation
that the THICK rope will form the "U" (bight) part, and the thinner rope will
be hitched to that (with its 270deg turn). People would be shocked to see
an image of a Sheet Bend with this orientation reversed--the thicker rope
turning 270deg through a bight of the thinner one.

NB: A SIMILAR CONSIDERATION APPLIES TO THE (EDK) OFFSET RING BEND !
The thinner rope should be that that makes the the initial (and one must
hope, effective) choking of the two ropes where they enter the knot body.
The thinner rope, in this position, will be pried outwards by loading, and
will be resisted in "rolling" by the greater bulk of the thicker rope (which
bulk is what will be pulled down into the choke of the thinner).
But oriented the other way, this potential advantage in different-diameter
ropes becomes a disadvantage, with the thicker more easily pried out
around a thinner partner, which in turn is more easily pulled down
through the thicker one.
Aggravating this vulnerability is the likely difference in elasticity: the
thicker rope will be dynamic, the thinner a less dynamic haul line.

.:. So, the ORB offers arguably/demonstrably BETTER behavior and safety
in the usual sort of mixed-diameter ropes that rockclimbers use; but it
needs to be formed with the above considerations attended to, in just
such a form (as presented in URLinks given by me above). To bolster
confidence and stability, tie off the thinner tail with an Overhand knot
around the thicker tail. (The prying open of the choking rope needs to
pull this tail down through the knot; this tied-off stopper prevents that.)

*kN*