Twin bridges on treemo

I just run a second TreeMo bridge with fisherman's on the lower Ds... with a little slack taken out of the original to equalize the two.
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Plenty of space for lanyard carabiners in the lower Ds with the bridge there as well.
 
John@TreeXP said:
This is the knot. It's not a Steveadore.

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Oh boy, now bashing my head against a wall. It looks like we need a new name in the double overhand knot family.

To me it is a undressed triple overhand tied onto the working end. A stevedore is a double overhand dressed differently. A double overhand tied around the working end is a scaffold/grape vine.

Now we are just arguing names. It’s the same construction just dressed and set differently. This difference is important because it can cause the knot to behave differently and potentially become unstable.
 
Crap not that im really doing anything anyway.. for clarity I’m just going to do doubles..

stevedore to double overhand. Never in ties just dressed differently
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Take the left hand turn, open it and pass it over to the right. Now dress and set
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evo said:
Oh boy, now bashing my head against a wall. It looks like we need a new name in the double overhand knot family.

To me it is a undressed triple overhand tied onto the working end. A stevedore is a double overhand dressed differently. A double overhand tied around the working end is a scaffold/grape vine.

Now we are just arguing names. It’s the same construction just dressed and set differently. This difference is important because it can cause the knot to behave differently and potentially become unstable.
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Maybe the more important question is if it's safer using just a two wrap or a three wrap. I'm guessing 3 is better than 2, but 2 usually is needed if the bridge length doesn't have enough slack.
 
John@TreeXP said:
Maybe the more important question is if it's safer using just a two wrap or a three wrap. I'm guessing 3 is better than 2, but 2 usually is needed if the bridge length doesn't have enough slack.
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With a grapevine there is no added strength between a double and triple I believe. Saw some testing. I think the more important question is “if how that knot is dressed on your bridge safe” show me examples of it in the industry or testing then will shut up
 
John@TreeXP said:
I hear you and I don't have proven case studies to draw from. We all have to make our own choices.
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Exactly my point.. just be careful and inform others before they copy yours. I have no problem with folks mucking around and trying new things. It the only way things change, but it needs to be defined as such. Enjoy the great thaw
 
Here's a few final thoughts...

A secondary rope bridge doesn't require PPE, as long as the primary connection point utilizes the primary bridge, with the secondary bridge used as a back-up rope bridge for added safety.

Accessories items like the DMM Captain throw hook, are not necessarily for PPE either, so connecting it to a secondary bridge is a calculated manuver with relative security, since the secondary rope bridge also isn't for PPE. However, the new Evo climbing harness from TM, enables the climber to use either, or both, rope bridge's as a primary rope bridge.

As for using a secondary rope bridge as a stand alone rope bridge, that's another matter and it should be thoroughly vetted, tested and proven worthy up to a minimum of 22kN, especially when a secondary rope bridge is used in the same way as the primary rope bridge.
 
DSMc said:
John, certainly use what you want, but can you explain what it is that keeps you from using a real scaffold knot and thereby making all other discussion moot.
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By all means, please enlighten us with a demonstration of a "real scaffold knot". Larger diameter ropes may not knot up as well as smaller ones, so feel free to provide more than one example, preferably with photos and videos, when used specifically for a secondary rope bridge on a lower d-ring. While you're at it, please list the makes of the ropes you find most suitable for a use as a rope bridge too.
 
Do your own homework.
As a general rule a properly tied, dressed and set scaffold is among the strongest knots. Is slips less so shorter tails can be used. Backup stoppers are not needed. It’s small and compact compared to other knots for similar applications. It locks down onto small diameter hardware.
It has a few cons, biggest is it can be a pain to untie if knotted around a object which can’t be slipped out.
 
Thanks for the helpful pointer. A Scaffold knot, aka double fisherman's knot is clearly a top choice for connecting a rope to a d-ring. I'm not opposed to learning something new and while we can all make mistakes, I'm glad we have a sounding board like this to work through this stuff. I see the scaffold has some steveadore characterisitcs too. For this intended purpose, I will use it from now on and I appreciate everyone's constructive advice.
 
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Bob Bob said:
daigentanoen on youtube has been using 2 bridges running through 1 large swivel. It looks like he is using a different method to attach the 2nd bridge to the d's. You can see his set-up in the video below...I'm not recommending this method, just presenting an option...
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It wasn't obvious to me in the video as to exactly how the guy secured his two bridges. It appeared a few times in there as if it was exactly like the evo arrangement, but he looks to be using the original TM D's, which I'd be shocked if they had enough room for two rope diameters to pass through the lower/smaller part of the D. However, it did appear like there were two stacked double-overhand stopper knots (or some closely-related knot) on there, together.

Screen caps from video of each side:
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