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Best way to tie two ropes together for rapping?
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By Jason Halladay
Administrator
From Los Alamos, NM
Sep 21, 2010
Climbing at the Belvedere crag near Nago with a great view of the northern end of Lake Garda and the town of Torbole sul Garda below. June 2013.

SlowTrad wrote:
Anyone use a different knot for a 10mm and 8mm line?


I still use a flat overhand. If the rope diameters vary more than 3mm, I go to the double fisherman. I think I read this 3mm variance suggestion in Alpine Climbing: Techniques to Take You Higher


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By Cota
From Bend OR
Sep 21, 2010

SlowTrad wrote:
I started using an 8mm tag line to do double rope rappels this year. While climbing next to an AMGA guide in the Needles SD, he commented that the only way to join two ropes of such different diameters is with two figure eight on a bight, with the loops joined. This necessitaates tying one 8 on bight, and one 8 follow through, with stopper knots on each. We never had a problem pulling ropes, but the knots are cumbersome to tie at a hanging belay. Since you always pull the tag line, if the rope hangs, you would be stuck with the tag line and not the rope to re-ascend. Anyone use a different knot for a 10mm and 8mm line?


should I go off on a tangent about how I think that AMGA is a worthless institution, and how a hell of a lot of their guides have MINIMAL real world experience....Nah, I have said it enough.


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By icymonsters
From ct
Sep 21, 2010

am I the only one that uses a square knot? safe and easy to untie


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By steve edwards
From SLC, UT
Sep 21, 2010

Brian,

We should. Do I still have your info? Shingo and I keep talking about getting a weekly cocktail hour going.

On the EDK, one of the areas it fared the weakest was when wet. Still plenty strong, mind you, but I think one of the ratings tests dropped it to 490 when wet. Course that's inversion, which still should be fine with enough tail. So we're probably all going on about something that is irrelevant as long as we properly tie our knots.

The reason I ask about my follow through on the tie in was that a gym employee nixed it once, saying something like "I saw a guide in Yosemite pull this knot right open." We asked how and he had no idea so we figured our combined 50 years of experience trumped his "I work in a gym" chest puffing but I never wanted to be one of those nailed-boots-were-fine-for-me-and-my-hardman-friends-so-I-don't-need-any-lightweight-BS-advice-from-you-whippersnapper-punk old farts so all of my conventions will always be up for review.

Quite happy to have learned something here today. Now excuse me while I go kick some kids off my lawn.


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By Cor
Sep 21, 2010
black nasty

thanks john,

i was just dealing with this on sunday so i could tie two cordelettes togather for a rap anchor... at least i remembered the rolling trick to loosen up the double fishermans. i will have to look into this more to satisfy my edk cordlette craving.

cor

ps: hey slim, you got any #'s on these knots??


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By Derek W
Sep 21, 2010
First summit of First Flatiron

Cor wrote:
i was wondering about a edk for a cordelette instead of a double fishermans. it could be untied real easy for a number of tasks that you may use a cordelette for. anyone have any wisdom on this?


I too would be interested in some numbers. I took a course from the BRC last spring and that is how they taught us to tie our cordalettes because it was "strong enough" and much easier and faster to untie if you need to. I tie the EDK with another one cinched up behind it as a back up and have been happy (and alive) so far.

steve edwards wrote:
On that note, since some of you are pretty into this, what about following your tail back through your fig 8 tie in knot? My understanding has always been that this both increases the size (strength) of the knot as well as making it easier to untie. Any revelations in the last 20 years?


I used to back up my fig 8 tie in this way. I'd heard it called the "yosemite back-up". In the course mentioned above, our guide said that it is possible to cause that to roll and capsize as well. I'm not sure I understand it though. He said mainly if you were to clip into the loop you tied into with an "alpine style" harness with no belay loop (which applies similar forces as tying 2 rap ropes together with the fig 8 EDK) and then there is no tail for it to roll up to, since it's tucked back in. Anyway, *his* verdict is a fig 8 without a back up is stronger and safer than a fig 8 with the tail tucked back in.

Again, if anybody has any hard evidence I'd love to hear it!


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By Jeff Fiedler
Sep 21, 2010

For two different diameters, I've used a double sheet bend ... and didn't die.

www.cruising.sailingcourse.com/images/double_sheet_bend.jpg

Have seen it taught in self rescue climbing courses, and its a standard knot in sailing.

Pretty simple to tie and evaluate; relatively low bulk.

Edit: Meant to add: Welcome feedback, and haven't seen strength test data for this knot.


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By Brian in SLC
Sep 21, 2010
Climbing in Smuggler's Notch

steve edwards wrote:
Do I still have your info? Shingo and I keep talking about getting a weekly cocktail hour going. On the EDK, one of the areas it fared the weakest was when wet.


Maybe? Pop me an email and/or I'll do the same. Got a new point-and-shoot, need to climb with it to see how it works... Cocktail hour would be great.

Speaking of wet EDK's, a few years back, I did some tests at home. Summary below.

-Brian in SLC

"Rappel with overhand knot ala "EDK": home testing...."

Thought this might be kind of interesting...

Rappel knots, for tying two ropes together, seems to be a constant debate in some climbing circles. There's some test data out there and some vague testimonial on overhand knots collapsing (rolling) under load, or coming unraveled. A bit disconcerting for those of us who use an "EDK" ("euro death knot") or in-line overhand (aka, flat overhand, abnormal overhand, etc) for rappelling.

So, thought I'd reassure myself that everything is o.k.

Grabbed two ropes. Yellow rope is an 8.5mm Beal circa 1985 (long since retired). Red rope is a 7.8mm Bluewater Ice Floss circa 1994 (also retired).

Thread red rope through a rapide which was hanging loosely whilst clipped to a carabiner hanging off my Metolius Simulator hang board (firmly mounted to the stairwell wall, thank goodness). Matched end of yellow rope to red and tied an overhand knot, thereby simulating how I'd do it when "in the field".

Left short tails and a loose knot each time. Donned harness, clipped rappel device (Wild Country Variable Controller was handy on the gym harness) to belay loop, and carefully, so as to not tighten or load the knot connecting the two rope, positioned both rope strands to be in effect, "on rappel". Took out as much slack but was very careful that there was no complete straightening of either rope strand and no tightening of the knot. Then, slight bunny hop up (credit card check!), cut my feet out, keep brake hand tight, and come down hard onto the rappel device with the full force of my 100 kilo body weight. Did this multiple times, but, took photos of three different situations. First: rope dry. Second: rope wet. Third: rope frozen.

Lets see the results.

Test #1: Dry Ropes

EDK dry and loose pre loading
EDK dry and loose pre loading


In the photo above, you can see the tails are way too short for comfort, and the knot is very very loose. Quite poorly tied. I'd never rappel on this in the field, ever. But, since the only penalty points would be a bruised tailbone, I loaded this baby up.

EDK dry loaded
EDK dry loaded


Knot snugged up. Knot did not collapse and/or roll. The tails didn't lose much length. So, no problems noted.

Test #2: Wet Ropes

Second test, ropes left soaking in the sink (and lightly massaged) until saturated. Removed ropes from sink, dripping wet, repeat the above test.

EDK wet and loose pre loading
EDK wet and loose pre loading


Note the loose knot (can see through the middle of the bottom of the knot). Tails still too short for comfort. Rope ends dripping on floor, time to load this puppy up.

EDK wet after loading
EDK wet after loading


Pretty good spray of water as the knot cinched down hard. No noticeable slippage, no capsizing and/or rolling. Just rapid tightening as per test #1.

Test #3: Frozen Ropes

Ok, finale time. Ropes put back in sink and allowed to soak up more water. Then, into the freezer, in a plastic bag. Several hours pass, then out of the freezer. Big mass of frozen glop. Had to physically tear the frozen ropes apart, but quickly as I wanted to limit the thawing. Threaded the frozen red rope through the rapid, quickly tie a loose overhand knot.

EDK frozen pre loading
EDK frozen pre loading


Can still see air through the knot above. Ice visible on parts of the rope. No time to waste, I go on rappel and jump on it.

EDK frozen post loading
EDK frozen post loading


And...ditto the above. Knot cinched down, no rolling and/or capsizing.

These results made me pretty happy. I use a single EDK quite often to tie two ropes together for rappelling. Its easy to tie, easy to inspect, low profile, easy to untie after the rappel. I cinch the knot down pretty tight and leave 18" tails. KISS works for me. The EDK aka in-line overhand knot makes some folks nervous. And...that's o.k. Use whatever you feel is best for you.

YMMV....


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By JPVallone
Sep 21, 2010

Toby B wrote:
What makes the EDK easier to pull than a double fisherman's? Seems like both would be equally prone to getting stuck in constrictions etc.


Tony the EDK can roll over edges, yes it can still get stuck, but less likely then a double fishermans


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By Sunny-D
From SLC, Utah
Sep 21, 2010
Top of Jah-Man Sister Superior

When doing ropes of different diameters I use a doubled Sheet-bend or a EDK doubled. The sheet bend is made especially for joining ropes of different diameters together and works really well. You can back up the ends with double fisherman knots that don't cinch down on themselves.


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By steve edwards
From SLC, UT
Sep 21, 2010

Brian,

Nice demo. Pretty much sold on the EDK now for anything in the backcountry (not rigging or controlled situations but I'm sure it's fine there, too, as long as you're hauling people and not a truck or something). I figured this might be the case. I've never had a knot slip at all (using flat fig 8 or EDK) and I've ab'd off under all sorts of duress in crap situations. Maybe I've been lucky but the more I read the more I believe knot failures are user error.

Cocktail party may be in order later this week. Perhaps a bit o'craggin' too.


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By Anthony Baraff
From Paris, France
Sep 22, 2010
Another Anthony (me) on Unnamed BP #2.

icymonsters wrote:
am I the only one that uses a square knot? safe and easy to untie


I'm going to assume that you're just trolling and not serious.


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By will smith
From boulder
Sep 22, 2010

The one you trust should be the one used. I like the square knot with fisherman on the ends as backup. Super easy to untie. I would NEVER use just a square knot.


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By Buff Johnson
Sep 22, 2010
smiley face

Jeff Fiedler wrote:
For two different diameters, I've used a double sheet bend ... and didn't die. www.cruising.sailingcourse.com/images/double_sheet_bend.jpg Have seen it taught in self rescue climbing courses, and its a standard knot in sailing. Pretty simple to tie and evaluate; relatively low bulk. Edit: Meant to add: Welcome feedback, and haven't seen strength test data for this knot.


If I were looking at only strength & ease to untie after loading, this is the best knot. It's the knot of choice for our rescue loads; possibly 600kg static. It's not a low bulk knot, that thing catches all kinds of rock.

We're not looking at getting the most strength that we possibly can here, we don't need it. We're moving fast and rapping with maybe 75-90kg static (ballpark average); double that if assisting a buddy. The flat overhand serves this purpose as the most effective & efficient knot along with a viable safety factor; even with that 10/8 diameter difference, it's fine.


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By Sisyphus
From here and there
Sep 22, 2010
willie

Anthony Baraff wrote:
I'm going to assume that you're just trolling and not serious.


I have rapped off of the square knot, albeit unhappily. Had a partner who really liked, and could not be convinced to use anything else. I did back it up with fishermans however. Not entirely sure I wouldnt fight for a different knot now though.


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By Jon H
From Boulder
Sep 22, 2010
At the matching crux

Cor wrote:
on another note... what is the stregnth of the edk, and the stregnth of a double fishermans? i was wondering about a edk for a cordelette instead of a double fishermans. it could be untied real easy for a number of tasks that you may use a cordelette for. anyone have any wisdom on this?


Why tie any knot at all in your cordelette? Just leave the untied ends of the cord hanging down at your masterpoint. You will still have a MP of 2 loops which is fully redundant, and you don't have the added bulk of a knot on your harness.

John Long's equallette only has a 2 strand MP so I'm not concerned about losing a strand.

I started doing this a while back and have no regrets at all. It's double useful when using 5.5mm spectra - no triple fisherman to really bulk things up.


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