Light Cordelette Options?

I guess I am used to the equalette, as described by Long and Luebben in their two books.

John Husky wrote:I guess I am used to the equalette, as described by Long and Luebben in their two books.

You're the one?

Certainly, I agree that anchoring in with the rope and sometimes runners is best, lightest, fastest, and most convenient. But carrying 20' of titan provides one more option if you want it and more importantly it can be quickly and inexpensively chopped up and used for bailing.

Derek Doucet wrote: That said, if we treat my hypothetical example of the factor 2 taken by the 165lb leader as a totally static belay, the impact force would exceed 14kn.

The UIAA mandates ropes have a maximum impact force rating of 12 kN. The rope with the highest impact force on the market that I know of right now is rated for 10.4 kN. Granted that is tested on a factor 1.77 fall, but it is also tested with an 80kg rigid weight which is roughly equivalent to a 100kg flexible mass. So in other words, it is pretty much impossible to hit 14 kN on a factor two using dynamic rope on a true FF2 fall.

Now, if by factor two you actually meant more like factor 1.9x where the belayer clipped the belay station, then that is a bit different. But even then, 14 kN would only be possible if you were doing a roped solo with the rope physical tied to the belay station, or under one other extremely specific example I will share below. See, if you actually did take a factor 1.9x fall with the rope clipped to the belay, the belayer would get pulled all the way up to the piece and the belay device would hit the biner catching the load. At that point you eliminate the 2:1 mechanical advantage that is produced when you take a lead fall and you are left with a 1:1 just as you would have had you fallen directly into the belay without clipping any intermediate pieces. By eliminating the 2:1 mechanical advantage (technically it is more like 1.6:1) you are looking at a solid 60% drop in impact force on the top piece.

Now earlier I did say that there was one specific example in which 14 kN may be plausible. If the slings the belayer used to tie into the belay were too short to allow him or her to be pulled up to the top piece which would preserve the 2:1 mechanical advantage created in a lead fall. However, even in that example it would still be very hard to hit 14 kN. See, a 14 kN load on the top piece would translate to around a 8.4kN load on the belay device and no modern plate belay device would provide enough friction to allow you to stop that type of load. You would have to be using a GriGri, and even then a GriGri cannot stop that much force, it would still slip. So unless you are roped soloing, a 14 kN load on the top piece is going to be extremely difficult to achieve which is probably why we have never heard of someone breaking a full strength cam or nut despite the known fact that FF2 falls do happen on occasion.

Anyway, I know you mentioned a static belay, so I am not really arguing with you, I am just throwing that info out there as to why it is very hard to actually hit 14 kN outside of roped soloing.

20 kN wrote: The UIAA mandates ropes have a maximum impact force rating of 12 kN. The rope with the highest impact force on the market that I know of right now is rated for 10.4 kN. Granted that is tested on a factor 1.77 fall, but it is also tested with an 80kg rigid weight which is roughly equivalent to a 100kg flexible mass. So in other words, it is pretty much impossible to hit 14 kN on a factor two using dynamic rope on a true FF2 fall. Now, if by factor two you actually meant more like factor 1.9x where the belayer clipped the belay station, than that is a bit different. But even than, 14 kN would only be possible if you were doing a roped solo with the rope physical tied to the belay station, or under one other extremely specific example I will share below. See, if you actually did take a factor 1.9x fall with the rope clipped to the belay, the belayer would get pulled all the way up to the piece and the belay device would hit the biner catching the load. At that point you eliminate the 2:1 mechanical advantage that is produced when you take a lead fall and you are left with a 1:1 just as you would have had you fallen directly into the belay without clipping any intermediate pieces. By eliminating the 2:1 mechanical advantage (technically it is more like 1.6:1) you are looking at a solid 60% drop in impact force on the top piece. Now earlier I did say that there was one specific example in which 14 kN may be plausible. If the slings the belayer used to tie into the belay were too short to allow him or her to be pulled up to the top piece which would preserve the 2:1 mechanical advantage created in a lead fall. However, even in that example it would still be very hard to hit 14 kN. See, a 14 kN load on the top piece would translate to around a 8.4kN load on the belay device and no modern plate belay device would provide enough friction to allow you to stop that type of load. You would have to be using a GriGri, and even then a GriGri cannot stop that much force, it would still slip. So unless you are roped soloing, a 14 kN load on the top piece is going to be extremely difficult to achieve which is probably why we have never heard of someone breaking a full strength cam or nut despite the known fact that FF2 falls do happen on occasion. Anyway, I know you mentioned a static belay, so I am not really arguing with you, I am just throwing that info out there as to why it is very hard to actually hit 14 kN outside of roped soloing.

You're correct of course, and I didn't intend to be misleading. Sorry if it came across that way. My point was that, even allowing for all of the energy disappating components in a typical belay system, it is entirely possible that a factor 2 fall on to an anchor contructed with single strands of 6mm perlon will generate forces in excess of that cord's breaking strength with knots tied in it.

I threw out the 14 kN figure as the theoretical maximum based on a static belay when someone proposed that I was not accounting for the other elements of a typical belay system in stating my concerns. I was, and in fact assumed that the actual forces generated would be reduced by as much as 50% from the theoretical static belay scenario. This is still enough to snap a knoted single strand of 6mm perlon, and should be of very real concern to proponents of 6mm single strand anchors.

Once again, sorry if I came across as misleading. That wasn't my intention.

20 kN wrote: The UIAA mandates ropes have a maximum impact force rating of 12 kN. The rope with the highest impact force on the market that I know of right now is rated for 10.4 kN. Granted that is tested on a factor 1.77 fall, but it is also tested with an 80kg rigid weight which is roughly equivalent to a 100kg flexible mass. So in other words, it is pretty much impossible to hit 14 kN on a factor two using dynamic rope on a true FF2 fall. Now, if by factor two you actually meant more like factor 1.9x where the belayer clipped the belay station, than that is a bit different. But even than, 14 kN would only be possible if you were doing a roped solo with the rope physical tied to the belay station, or under one other extremely specific example I will share below. See, if you actually did take a factor 1.9x fall with the rope clipped to the belay, the belayer would get pulled all the way up to the piece and the belay device would hit the biner catching the load. At that point you eliminate the 2:1 mechanical advantage that is produced when you take a lead fall and you are left with a 1:1 just as you would have had you fallen directly into the belay without clipping any intermediate pieces. By eliminating the 2:1 mechanical advantage (technically it is more like 1.6:1) you are looking at a solid 60% drop in impact force on the top piece. Now earlier I did say that there was one specific example in which 14 kN may be plausible. If the slings the belayer used to tie into the belay were too short to allow him or her to be pulled up to the top piece which would preserve the 2:1 mechanical advantage created in a lead fall. However, even in that example it would still be very hard to hit 14 kN. See, a 14 kN load on the top piece would translate to around a 8.4kN load on the belay device and no modern plate belay device would provide enough friction to allow you to stop that type of load. You would have to be using a GriGri, and even then a GriGri cannot stop that much force, it would still slip. So unless you are roped soloing, a 14 kN load on the top piece is going to be extremely difficult to achieve which is probably why we have never heard of someone breaking a full strength cam or nut despite the known fact that FF2 falls do happen on occasion. Anyway, I know you mentioned a static belay, so I am not really arguing with you, I am just throwing that info out there as to why it is very hard to actually hit 14 kN outside of roped soloing.

It´s worth noting that while it would be uncommon to get 14kN on a belay (or elsewhere) it is by no means impossible, thus bolt manufacturers are required to have a minimum strength of 25kN radially and slings and karabiners must get 20kN or more.
Those who decide on the standards are aware that a)there may be more than one climber involved in either the fall or at the belay, b)climbers can weigh more than 100kg when fully equipped, c) the maximum rope impact is for a new rope and may rise with age and use, d)slippage through the belay device cannot be guaranteed as a simple tangle in the rope may prevent this.
It´s also worth noting that the slip values for the Grigrei are without a belayer, with someone holding the rope these are considerably higher. There is also another commonly used device which has slip values far higher than the GriGri, 9.54kN being interesting to say the least as it is higher than the rateds force for the rope tested! (And no, I´m not telling you what it is).

As to thinness of cordalettes;-as part of the DAV investigations into these the University of Stuttgart drop tested various cords clove hitched singly into a karabiner, thin Dyneema tape and Spectra cord failed their own requirement of 6kN.

Jim Titt wrote: It´s worth noting that while it would be uncommon to get 14kN on a belay (or elsewhere) it is by no means impossible, thus bolt manufacturers are required to have a minimum strength of 25kN radially and slings and karabiners must get 20kN or more. Those who decide on the standards are aware that a)there may be more than one climber involved in either the fall or at the belay, b)climbers can weigh more than 100kg when fully equipped, c) the maximum rope impact is for a new rope and may rise with age and use, d)slippage through the belay device cannot be guaranteed as a simple tangle in the rope may prevent this. It´s also worth noting that the slip values for the Grigrei are without a belayer, with someone holding the rope these are considerably higher. There is also another commonly used device which has slip values far higher than the GriGri, 9.54kN being interesting to say the least as it is higher than the rateds force for the rope tested! (And no, I´m not telling you what it is). As to thinness of cordalettes;-as part of the DAV investigations into these the University of Stuttgart drop tested various cords clove hitched singly into a karabiner, thin Dyneema tape and Spectra cord failed their own requirement of 6kN.

You are correct, although extremely uncommon, it is possible to hit 14 kN in roped solo falls or other very specific examples. Also, slings are actually required to hold 22kN where as carabiners are required to hold 20kN (except ovals). Also, harnesses are required to hold 15 kN where as ropes are limited to a maximum impact force of 12 kN. I have always wondered why this is. I assume the UIAA has a slightly higher strength requirement for textile products to account for some level of wear which may reduce the strength of the product, but that is only a guess. I have always wondered what the correct answer to that is.

Derek Doucet wrote: You're correct of course, and I didn't intend to be misleading. Sorry if it came across that way. My point was that, even allowing for all of the energy disappating components in a typical belay system, it is entirely possible that a factor 2 fall on to an anchor contructed with single strands of 6mm perlon will generate forces in excess of that cord's breaking strength with knots tied in it. I threw out the 14 kN figure as the theoretical maximum based on a static belay when someone proposed that I was not accounting for the other elements of a typical belay system in stating my concerns. I was, and in fact assumed that the actual forces generated would be reduced by as much as 50% from the theoretical static belay scenario. This is still enough to snap a knoted single strand of 6mm perlon, and should be of very real concern to proponents of 6mm single strand anchors. Once again, sorry if I came across as misleading. That wasn't my intention.

No problem, it was I that misunderstood your post.

A few questions for those that use Titan cord for cordelettes:

1) how easy is it to cut it up to use as rappel anchors for retreatings?

2) How stiff and slippery is it? Does it hold knots well? Can you use it to tie a prusik on a rope?

harpo-the-climber wrote:A few questions for those that use Titan cord for cordelettes: 1) how easy is it to cut it up to use as rappel anchors for retreatings? 2) How stiff and slippery is it? Does it hold knots well? Can you use it to tie a prusik on a rope?

1) Easy to cut up and use for retreating. A sharp knife goes right thru it.

2) It's pretty stiff, but not really slippery. It holds knots fine, but of course you have to take care when tying it because of the stiffness. Double fisherman's works well. Haven't tried it as a prusik, but it might be a little too stiff to work well in that application. Can't say for sure tho.

Titan cord (and other 5mm cord with spectra or dyneema in it) will work for a prussik, but it may need a bit more tending than you are used to with thicker/less slippery material. I have used it in this application several times to good effect, and in fact have used other nylon-only cord so infrequently that I can't really compare with the amount of tending the other stuff takes, so maybe it isn't that much more for titan cord. The prussik knot will need at least two full wraps, but this is sort of the standard minimum size for the knot anyway. If you're heavier or hauling more gear weight, then consider three wraps. I have always hand-tended my prussik knots, ensuring they engage before fully weighting them anyway.

not mentioned is that Titan Cord is 2-5x the price of nylon options. Thicker cord holds up better as well, you'll be replacing that thin tech cord more often.