Joining two ropes with a lashing for a rappel

Marc801 Cwrote:

Rapping and/or ascending a 6mm cord?
No, thank you. 

Even if it had an over 2000kg break load and was EN and UIAA-certified?  Would it just be the optics of such a skinny rope?  It takes some getting used to, I know, but engineering doesn't lie...

Would you do it on 8mm?

@Gavin: the R8 you're using has a thicker cover than what I'm designing, to give it that nubbly feel.  That's at the cost of a thinner core, and added difficulty in splicing. I'm using something more akin to Marlow D2 Race, where there's a maximum of Dyneema in the core.  But yes, I'm hoping when I have a product well-developed, to probe the ski-mountaineering market.

As for a video of the thread's topic in use: stand by, and I'll chuck one up on my YouTube channel soon.

Ben Zartmanwrote:

I have spoken to Ryan Jenks, but since he's running a retail store, he's unwilling to make a video of gear he isn't willing to sell, especially since it's better than anything he's currently offering.

I find it really strange because Ryan routinely tests janky gear. Also, I find it incredulous that he would say that your "gear is better than anything" he sells - since up to this point you haven't presenting any objective verifications of the claimed benefits of your products. 

Ben Zartmanwrote:

Is the cost really the only objection?

Your product, at the claimed strength of 10 kN, is inferior to all the similar products on the market, and with the typical strength reduction when ultra-static materials are used with a knot or hitch to secure a masterpoint, may have low enough levels of strength to fail at loads that are possible in climbing scenarios.

Your continued insistence that you have a superior product, despite the aforementioned basic facts to the contrary, are troubling for a business selling safety critical products to the public.

you just don't think there's an improvement with spliced rope over webbing?

This is not about splicing vs. sewing, it's about overall product capabilities and the requirements of the application.

  All the load-bearing fibers of that webbing are exposed to sun and chafe, where mine are protected from both.

While this is probably not really an issue in typical use, if this is something that people are concerned with, there are multiple offerings from trustworthy companies that also have sheaths over a load-bearing core.

Ben, I was watching a few of your splicing videos on Youtube and did a search to find your webstore. I ended up finding a Chris van Leuven story about you on Gripped from a couple years ago, which is really interesting and talks about your climbing cred and other history. Am posting this for others here:
https://gripped.com/profiles/ben-zartman-i-was-the-ultimate-climbing-and-sailing-dirtbag-i-had-no-car-or-money/

I'm looking forward to seeing the video that Slim suggested of how the spliced eyes work.

i don't really understand what the innovation might be here...? if you have 2 ropes with spliced-end eyelets, and if joining them with a knot or locker is "too bulky" for some obscure reason, I'd then use a quicklink, which would not be any bulkier than a spliced end. 

@amarius: Ryan tests gear that has been sun-cooked, abused, or is inferior or equal to what he's peddling.  For him to test something better would beg the question: why not stock it in his store?

@Kyle: the Anchor Extender is weakest in single-strand: so are all the other anchor products you linked to earlier, which being Spectra or Dyneema themselves, have the same static properties as mine.  When used as intended, to build an equalized anchor, where you wind up with a minimum of two strands, even if you tie a BFK (I prefer a girth hitch to the masterpoint 'biner as stronger), it's massively stronger than any load reasonably to be expected in climbing.  And if you can figure out how to shockload a static anchor without something having gone horribly wrong, your imagination is commendable.

@Terry, thanks for the kind words.  I have just now posted the requested video on my YouTube channel at Zartman Rigging.  https://www.youtube.com/watch?v=Xe2V8m-q-j4

Let's see if that link works.

Fan Ywrote:

i don't really understand what the innovation might be here...? if you have 2 ropes with spliced-end eyelets, and if joining them with a knot or locker is "too bulky" for some obscure reason, I'd then use a quicklink, which would not be any bulkier than a spliced end. 

He's not selling lockers or quicklinks

PWZwrote:

He's not selling lockers or quicklinks

I'm not selling lashings either: this thread was to float an idea to judge the herd's gut reaction to it.  I don't yet offer the sort of rope I'm ultimately envisioning for this application.  Product development is a long and expensive process, and some avenues may not be worth pursuing commercially (for my own use, I'm already there) if people can't wrap their heads around them.

Ben Zartmanwrote:

Even if it had an over 2000kg break load and was EN and UIAA-certified?  Would it just be the optics of such a skinny rope?  It takes some getting used to, I know, but engineering doesn't lie...

No, it doesn't matter. I don't like using such a skinny rope for anything other than a tag line/pull cord. I  don't really care what the engineering and certification specs say - for me it is indeed the optics.

Would you do it on 8mm?

I've rapped on an 8mm static and that's the lowest I would go. As far as jugging, I don't even like that on a 9mm.

Ben Zartmanwrote:

When used as intended, to build an equalized anchor, where you wind up with a minimum of two strands, even if you tie a BFK (I prefer a girth hitch to the masterpoint 'biner as stronger), it's massively stronger than any load reasonably to be expected in climbing.

Dyneema cords generally lose ~50% of their strength when tied in a knot, so your 2-strand anchor can fail at loads of ~5 kN on a leg.  Very few people would consider that an acceptable climbing anchor.  All of the other products have a significantly higher MBS (14 to 17 kN single strand), and also may retain higher level of strength when knotted.

the Anchor Extender is weakest in single-strand: so are all the other anchor products you linked to earlier, which being Spectra or Dyneema themselves, have the same static properties as mine.

A 100% dyneema product will lose ~40-50% of strength in a knot.  The Ultratape used in the Mountain Tools product is different construction, and a blend of dyneema and nylon.  The testing done by Moyer (et al) in 2000 suggests that it retains more like 80% of its strength when tied in a knot (~11 kN), and that a single arm of it fails above 12 kN in a tied anchor configuration (compared to likely 5-6 kN for yours).

Marc801 Cwrote:

No, it doesn't matter. I don't like using such a skinny rope for anything other than a tag line/pull cord. I  don't really care what the engineering and certification specs say - for me it is indeed the optics.

I've rapped on an 8mm static and that's the lowest I would go. As far as jugging, I don't even like that on a 9mm.

The issue is t break strength but rather resistance to severing. Rapping on rock on 6mm is borderline suicidal behavior. Maybe if I were free-rappelling I would consider it.

Jared Ewrote:

The issue is t break strength but rather resistance to severing. Rapping on rock on 6mm is borderline suicidal behavior. Maybe if I were free-rappelling I would consider it.

This seems quite situationally dependent. For one - some areas/routes have more sharp edges than others, and another is the makeup of said rope. There are many 6mm ropes on the market these days that are made with technora/dyneema that are very cut resistant (I would imagine much moreso than, say, a thin twin rope that is all nylon). Technora sheath/dyneema core, or all dyneema like the Pur line are shockingly difficult to cut even with scissors or a knife.  

Slim Pickenswrote:

Ben, I have a request. Would you be willing to make and post a video of yourself setting this up? Doing so at a mock anchor station would be ideal if you’ve got access to one, though not strictly necessary. Please start with two of your spliced eye ropes separated, and demonstrate the process of connecting those two ropes via your dyneema lashing.

I think seeing this in action may serve to help us understand what we, collectively, seem to be missing. Conversely, it may cement for us why we prefer the current norms.

Thank you for your consideration. 

Ben, thanks for taking the time to make and post the video. I like your sweater very much.

Having watched the video, I appreciated seeing the process in action. The thing that it comes down to for me is just that it's an incredibly impractical amount of faff compared to the time that it takes to tie a flat overhead bend. I can tie and dress two ropes together with a very simple knot in 2 seconds. I can do it from a hanging belay, I can do it by headlamp, I can do it when I'm totally shattered from a day's efforts, and my hands are shaky, and my eyes are bleary. 

For your system, instead of just tying a quick FOB, you're introducing this thin thread that then needs to be girthed to one rope, run multiple times through the other rope's eye, and then secured by a series of tiny hitches. I cannot imagine doing that when a storm is bearing down and I have to bail. I can't imagine doing that in the dark. I can tie a FOB with gloves on—can I construct this lashing  with gloves on? No way. 

It's kind of neat, your system. I like these thin techy ropes, and the craft of splicing is cool. I've thought of wanting to learn to splice for customizing lanyards and stuff like that. And while a lot of this conversation has focused on people's doubts about the strength and safety of this system, I can't even get that far. The far greater complexity of this compared to just tying a simple knot makes something like this a total non-starter. 

Slim Pickenswrote:

Ben, thanks for taking the time to make and post the video. I like your sweater very much.

Having watched the video, I appreciated seeing the process in action. The thing that it comes down to for me is just that it's an incredibly impractical amount of faff compared to the time that it takes to tie a flat overhead bend. I can tie and dress two ropes together with a very simple knot in 2 seconds. I can do it from a hanging belay, I can do it by headlamp, I can do it when I'm totally shattered from a day's efforts, and my hands are shaky, and my eyes are bleary. 

For your system, instead of just tying a quick FOB, you're introducing this thin thread that then needs to be girthed to one rope, run multiple times through the other rope's eye, and then secured by a series of tiny hitches. I cannot imagine doing that when a storm is bearing down and I have to bail. I can't imagine doing that in the dark. I can tie a FOB with gloves on—can I construct this lashing  with gloves on? No way. 

It's kind of neat, your system. I like these thin techy ropes, and the craft of splicing is cool. I've thought of wanting to learn to splice for customizing lanyards and stuff like that. And while a lot of this conversation has focused on people's doubts about the strength and safety of this system, I can't even get that far. The far greater complexity of this compared to just tying a simple knot makes something like this a total non-starter. 

The macrame is definitely a bit silly, but it would be easy to replace with a soft shackle if there was any utility in carrying two statics with spliced eyes.

Kyle Tarrywrote:

Dyneema cords generally lose ~50% of their strength when tied in a knot, so your 2-strand anchor can fail at loads of ~5 kN on a leg.  Very few people would consider that an acceptable climbing anchor.  All of the other products have a significantly higher MBS (14 to 17 kN single strand), and also may retain higher level of strength when knotted.

A 100% dyneema product will lose ~40-50% of strength in a knot.  The Ultratape used in the Mountain Tools product is different construction, and a blend of dyneema and nylon.  The testing done by Moyer (et al) in 2000 suggests that it retains more like 80% of its strength when tied in a knot (~11 kN), and that a single arm of it fails above 12 kN in a tied anchor configuration (compared to likely 5-6 kN for yours).

You're now using "can" and "suggests" in place of real engineering.  

We won't know, until someone bothers to do comparative testing, how much a BFK will reduce the load-bearing of a single stand with an improperly equalized anchor.  I recommend against the BFK specifically because of the propensity of Dyneema to lose strength in a tight knot.  I expect it behaves differently in a BFK, since the turns are all more soft in that use.  But again, I recommend girthing the masterpoint 'biner, which retains 80% of the strength.  Still we won't know for sure until someone breaks a bunch of samples in a configuration not recommended by the manufacturer.

Incidentally, in testing for the UIAA, the Anchor Extender broke at over 11kN.  I put less than that on the rating tag to have a safety margin: you don't want people loading something close to break load without giving themselves a margin.  Likewise my Seamless runners broke above 25kN, but I tagged them at 24.

For the poster concerned with skinny ropes cutting: that's one of the virtues of that rope construction: Technora is very cut-resistant, and the Dyneema core even more so.  So an edge that would slice a fat nylon rope would be less lethal to those materials, even in a thinner diameter.

Slim Pickenswrote:

Ben, thanks for taking the time to make and post the video. I like your sweater very much.

Having watched the video, I appreciated seeing the process in action. The thing that it comes down to for me is just that it's an incredibly impractical amount of faff compared to the time that it takes to tie a flat overhead bend. I can tie and dress two ropes together with a very simple knot in 2 seconds. I can do it from a hanging belay, I can do it by headlamp, I can do it when I'm totally shattered from a day's efforts, and my hands are shaky, and my eyes are bleary. 

For your system, instead of just tying a quick FOB, you're introducing this thin thread that then needs to be girthed to one rope, run multiple times through the other rope's eye, and then secured by a series of tiny hitches. I cannot imagine doing that when a storm is bearing down and I have to bail. I can't imagine doing that in the dark. I can tie a FOB with gloves on—can I construct this lashing  with gloves on? No way. 

It's kind of neat, your system. I like these thin techy ropes, and the craft of splicing is cool. I've thought of wanting to learn to splice for customizing lanyards and stuff like that. And while a lot of this conversation has focused on people's doubts about the strength and safety of this system, I can't even get that far. The far greater complexity of this compared to just tying a simple knot makes something like this a total non-starter. 

I completely agree it's fiddly, and would be overmuch with frozen fingers.  I wasn't thinking of ease of use or practicality here: I was thinking of lightest, lowest profile method.  Every new thing, every process, every idea, starts somewhere, and often gets refined in a totally unexpected way.  A diamond-knot soft shackle has been suggested--there's a refinement right there, one that sacrifices low-ness of profile for convenience.  If spliced eyes ever become popular, do doubt something will evolve that's both strong, easy, and accepted by those who once doubted.  But we gotta start somewhere, and I, for one, am glad for the discussion and feedback.

Ben Zartmanwrote:

You're now using "can" and "suggests" in place of real engineering.

The numbers come directly from break test data.  Moyer is a good source on this, but HowNot2 has broken a bunch, Debruin (et al) also have.  You have posted zero data, so I don't think this is a fair criticism.

I recommend girthing the masterpoint 'biner, which retains 80% of the strength

That is not the case for girth hitching other dyneema products, so this would be an atypical result.  The failure mode is often slippage, not breakage; this has also been tested by multiple sources and the data is in the public domain (HowNot2, Debruin, Delap, etc.)

I expect it behaves differently

Please support with data.

We won't know, until someone bothers to do comparative testing, how much a BFK will reduce the load-bearing of a single stand with an improperly equalized anchor.

I provided this data and the source, for competing product (Web-O-Lette, see Moyer).  For your product, we can either assume it will be similar to other dyneema slings, or you can provide the test data.

Incidentally, in testing for the UIAA, the Anchor Extender broke at over 11kN.  I put less than that on the rating tag to have a safety margin

Responsible businesses don't just subtract 1 kN from the test data a call that a "safety margin."  You need to conduct enough testing to statistically analyze the dataset, evaluate the distribution, and then use a standardized reduction from the mean (3 sigma is common in many industries, including climbing gear).

Likewise my Seamless runners broke above 25kN, but I tagged them at 24

Sewn dyneema slings from Mammut test at 27+ kN.  BD Dynex slings test at 27 kN.  Both tag them at 22 kN.

Repetitive sawing motion of dyneema on nylon sounds fun

Ben Zartmanwrote:

A recent thread about knots (bends, really) for rapelling got me thinking: what if we could eliminate bends entirely, at least from some rappelling scenarios?  Something like the picture.  

 I

Since you already have eyes in the rope, why not just join them with one of those tiny keychain carabiners? Or maybe one of those velcro loops for tying up electrical cords? 

Ben, could you clarify what UIAA standard your 10kN anchor extender meets? Based on application, UIAA104/EN566 for slings would be most relevant, but that requires a 22kN MBS. Are you testing it to UIAA102/EN564 (accessory cord) instead?