Question about rappeling using two full ropes. One being in question.

Climbing with a partner on a two pitch route we had brought a second rope with us as to make a single rap instead of 2.

My rope is a 60m 10.5 Mammut
Partners rope is a 60m 10.2 or 10.5 BlueWater

I was only made aware that his rope has taken a number of falls at the end of the pitch and did not look like something I would climb on. I decided not to use his rope and instead use my rope doubled to descend in two rappels.

Although his rope would of most defenitely held a rap or maybe another whipper or 2 or 10, i did not like taking that risk, with that said, that got me thinking...

Scenerio:
two 60m ropes - one good, one not so much/questionable
need to descend 180 feet or so, must be single rappel.

what would be the best way to assure the safety?

YES i know the best answer is to NOT rap on sketchy rope, but my question, if I HAD to.

My assumption and something i would feel comfortable with is to tie both ropes with a figure 8 on both and traced back on each backed up with double fishermans (or just double fishermans) and tie and overhand knot on a bight on the GOOD rope and clip a biner.
Assuming the bad rope fails, at any point, the knot with a bight and a biner WILL NOT go thru the chainlinks stopping the climber from falling.

Am I correct? Is there a better way to do this?

Scenerio

Yes that will work. You can also set up your rappel this way and rap off of only the good rope (single rope rap) and use the bad rope as a tag line to pull down the rig once you're on the ground.

Hmm... if I understand you correctly, your knot should be big enough to not go through the chain link. That extra F8 with biner is pointless.

Solid question that deserves detailed thought. I would Reepschnur. Google "reepschnur rappeling" and youll find some variations on techniques. I would/use a alpine butterfly for the reepschnur knot.

Or this set-up for the tagline. It is a little cleaner.

tag-line

Biner block it. Knot together the ropes as normal and clove hitch a locking biner on the "good" rope side of the knot between the knot and the chains. This will isolate the rap strand from the pull strand. This has many uses. You can rap a full rope length using only 1 climbing rope and a much lighter cord to pull. (I've got a 5 mil static line) You can also isolate a strand for any length rap if you'd rather rap single strand. (GriGri)

the rope took a number of falls? no core shots?

to each his own...

definitely use the biner block in the above illustration

Solid question and analysis to solve the potential issue. As others have said a biner block or similar works.

Or set-up a Reepschnur rappel using only the good cord with the bad cord used for retrieval. See the following link for reference:
Reepschnur rappel technique

Mr Clean wrote:Or set-up a Reepschnur rappel using only the good cord with the bad cord used for retrieval. See the following link for reference: Reepschnur rappel technique

This is essential the same as what Brian is showing in his graphic.

How sketchy is the rope? If there are no core shots then Im sure your ok. Plus when you are repelling you are not putting nearly as much force as a dynamic fall. You would be surprised how much abuse a rope can take and still hold up. You are probably relying to much on the UIAA fall limit that the rope company sets on each rope. I was told that those UIAA falls are pretty big and casual climbers rarely put there ropes through that kind of force when falling.

Oh boy. When is someone going to blow the OP's mind and tell him that a well-tightened overhand knot is superior to a double-fisherman's, especially when tying rap lines together that have different diameters? (FYI, this single overhand style's strength lies in the ropes being pulled apart and tightening the knot on itself; so when using it, don't leave the knot straddled on the chains – leave it about six inches below the chains so the opposition forces are linear.) The overhand's lower profile is a nice feature, too, for avoiding snags.

I love watching a NOOB's eyes bug out when I tie lines together like this (leaving plenty of tail length, of course). Life-and-death matters just seem like they shouldn't be so quick and simple, like you should have to do something bigger and more involved, like a double fisherman's knot or something, but ... nope!

If the rope was in terrible shape with core shots I'd do an EDK with a biner block which would effectively turn the other rope into a very heavy pull cord. More likely you're over-thinking it and the second rope was fine to rap on.

You should be more worried about getting your rope stuck and with a fisherman's + figure 8 + locker you would be asking for one. Rope sticks on long raps can be very bad...much worse than worn out ropes.

D-Storm wrote:Oh boy. When is someone going to blow the OP's mind and tell him that a well-tightened overhand knot is superior to a double-fisherman's, especially when tying rap lines together that have different diameters? (FYI, this single overhand style's strength lies in the ropes being pulled apart and tightening the knot on itself; so when using it, don't leave the knot straddled on the chains – leave it about six inches below the chains so the opposition forces are linear.) The overhand's lower profile is a nice feature, too, for avoiding snags. I love watching a NOOB's eyes bug out when I tie lines together like this (leaving plenty of tail length, of course). Life-and-death matters just seem like they shouldn't be so quick and simple, like you should have to do something bigger and more involved, like a double fisherman's knot or something, but ... nope!

Nothing to blow my mind. Im aware that an overhand knot (EDK) is excellent for this. I have rappeled on it before with no issues. I, however, still prefer to use figure 8s or doublefishermans. I have no need for a flat side advantage that an EDK provides, most of the rappels have the chainlinks very close to the flat edges.

I just simply feel better with doublefishermans or a f.8

Thanks everyone for the input. This answers my question. My diagram was essentially correct to what everyone is mentioning, except my biner was not going thru the main rope. This makes sense. But i feel like the rope not clipped thru the good rope will still do the trick.

Thanks all

Roman

Many, many more people have died rapping on one line that was not rigged properly vs (what zero!) dieing b/c a rope failed during rappel.

Ropes don't break - they get cut.

You can't "use up" the number of falls.

Next time do this instead of using a 'sketchy' rope:

youtube.com/watch?v=b8Ute5c…

(but please don't)

Matt N wrote:Many, many more people have died rapping on one line that was not rigged properly vs (what zero!) dieing b/c a rope failed during rappel. Ropes don't break - they get cut. You can't "use up" the number of falls. Next time do this instead of using a 'sketchy' rope: youtube.com (but please don't)

Good god I would do the Texas Rope trick before that one... geeze

The theory is sound in a situation where you've got a skinny tag line. A fuzzy regular rope? Give me a break. That "sketchy" rope is probably 5 years newer and 200 whippers newer than any fixed line anywhere but the black (thanks PMI!!).

I own an frequently use a 6mm tag line. Here is what I do. I tie the two together with an edk, and after looking at it a while, I tie another edk with the tails. Then I spout some technical jargon to my partner about how it's OK because my partner will definitely not like how a skinny rope and regular rope look together. I always run the lead line through the chains, it sucks to pull with a skinny line sometimes but that's life.

My bigger issue is friction. If you've got a <9.5 tied to 6, you need to hang on tight. Add extra biners, tie a prussik, etc.

D-Storm wrote:Life-and-death matters just seem like they shouldn't be so quick and simple, like you should have to do something bigger and more involved, like a double fisherman's knot or something, but ... nope!

Despite no reported deaths from the EDK I still go with the FLAT double fishermans. Seems to offer all of the benefits of the EDK but like you said, gives the additional psychology of having "a little bit more" connecting the rope and practically screams at you if it is tied wrong.

Second knot in this link.

And your partner continued climbing on that rope and hasn't died yet.

The EDK will avoid so many problems when you start climbing a lot

nicelegs wrote:That "sketchy" rope is probably 5 years newer and 200 whippers newer than any fixed line anywhere but the black (thanks PMI!!).

Are you saying fixed lines in the Black are newer than the rest or are older than 5 years? ;)