Stiching cut strands

On a kernmantle rope, with the core taking the load, a repair to the cover would be like darning a sock. Only the opening and loose strands would have to be closed and contained.
Other rope constructions would have the cover sharing or taking the full load and would be difficult be repair to bring it back to original strength.
When making any repairs you would have to be careful not to sew the cover and the core together.
 
I mean stitching the core and cover together. It may retain strength if done well but I'm guessing the sloppy slack'd kill the idea dead, on db anyway.
 
I have a 24 strand double braid that has four picked strands. The inside core is still not visible and is unaffected. Assuming a 50/50 distribution of load, doing the math I still have 90% strength in this rope. Just for fun let's say I tie an Alpine butterfly over that defect to isolate it. Now my rope is down to about 65%. How much sense would that make?

I don't think you can consider the strength even if you could find a way to stitch those strands together because it's really not measurable.
 
yoyoman said:
I have a 24 strand double braid that has four picked strands. The inside core is still not visible and is unaffected. Assuming a 50/50 distribution of load, doing the math I still have 90% strength in this rope. Just for fun let's say I tie an Alpine butterfly over that defect to isolate it. Now my rope is down to about 65%. How much sense would that make?

I don't think you can consider the strength even if you could find a way to stitch those strands together because it's really not measurable.
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I'd guess that it is measurable to around 10-15%. Just as any other method, knotting/splicing/stitching is repeatable and measurable to certain parameters. Once the outer strands have been cut they and the rope are much more susceptible to further damage. End to end splices don't work in my mind cause of the amount of slack moving around, they can pop out way to easily. This may be a method for ropes other than db, if a method at all !
 
I'll guess that he is trying to join the ends of two ropes together without increasing the outside diameter.
IMG_1139.webp
On number one, the covers are slid back and the cores are each reduced by half, than laid on top of each other and the covers milked back together.
On number two, reduce the cores more than half and insert a piece of dyneema webbing for added strength.
On number three the cores are reduced by half and buried into each other, after being rebraided.
All three would need some kind of stitching to keep them together under low load. Testing would determine how long the buries would have to be.
 
Brocky said:
I'll guess that he is trying to join the ends of two ropes together without increasing the outside diameter.
View attachment 42035
On number one, the covers are slid back and the cores are each reduced by half, than laid on top of each other and the covers milked back together.
On number two, reduce the cores more than half and insert a piece of dyneema webbing for added strength.
On number three the cores are reduced by half and buried into each other, after being rebraided.
All three would need some kind of stitching to keep them together under low load. Testing would determine how long the buries would have to be.
Click to expand...
No, not that at all.
Sorry for the vagueness, I've been running around like a blue arsed fly. I'll do some pull tests on ideas and get back t'y'all about it.
 
Ok my second guess is......I don't have one. I thought it was TRT related and you needed a continuous loop. Oh well,I enjoyed working on that problem even though wrong.(Guess I don't win the prize either!)
 
Brocky said:
Ok my second guess is......I don't have one. I thought it was TRT related and you needed a continuous loop. Oh well,I enjoyed working on that problem even though wrong.(Guess I don't win the prize either!)
Click to expand...

Still a fun idea.
I need a continuous loop for long SRT ascent practice. I think @JeffGu was the one talking to me about it.
I got to climb something similar to the srt treadmill recently pulling out 6 natural redirects with a long rope. I ascended about 80 feet without going more than 6 feet off of the ground.
 
Ahhh - found it!

From Climbing Treadmill by Pete Sauvigne, Nylon Highway #35:

Making the splice is critical to the success of this system. A kernmantle rope is required, I use standard PMI. On each end of the loop piece: Pull out the core about 10 inches by aggressively sliding the sheath along the core. Cut off this piece of core, and slide the sheath back to its original position leaving a rope with hollow ends. It is helpful to fold back about 1 inch of the sheath and tape the end to keep it from fraying. Then insert a 12" piece of 5.5mm Spectra cord into the holes. The Spectra cord should bottom out against the original core. When it does, tack it down with a sewing awl to keep it in place. Take one end of the sheath, remove any tape and tie it to the Spectra cord with heavy awl thread about 1 inch past the center of the splice. Smooth out this side of the sheath and cut off any excess. Now overlap the other end of the sheath and tie it down with about 1 inch overlap. Again cut off any excess. Now whip the splice for about 1 1/2 inches over the sheath lap. Stitch through the sheath and the Spectra cord over the entire 12 inch length, including through the whipping. Make two stitching passes, 90 degrees apart. The splice will require periodic inspection and re-whipping every 200 revolutions or so. DO NOT USE 6mm nylon in place of the Spectra cord. Such splices break at about 30 revolutions, while my Spectra cord splice still holds after about 400. A rack will work for the rappel device, but it will tend to wear the splice more quickly.
​
sauvigne splice.webp
 
hatchetation said:
Ahhh - found it!

From Climbing Treadmill by Pete Sauvigne, Nylon Highway #35:

Making the splice is critical to the success of this system. A kernmantle rope is required, I use standard PMI. On each end of the loop piece: Pull out the core about 10 inches by aggressively sliding the sheath along the core. Cut off this piece of core, and slide the sheath back to its original position leaving a rope with hollow ends. It is helpful to fold back about 1 inch of the sheath and tape the end to keep it from fraying. Then insert a 12" piece of 5.5mm Spectra cord into the holes. The Spectra cord should bottom out against the original core. When it does, tack it down with a sewing awl to keep it in place. Take one end of the sheath, remove any tape and tie it to the Spectra cord with heavy awl thread about 1 inch past the center of the splice. Smooth out this side of the sheath and cut off any excess. Now overlap the other end of the sheath and tie it down with about 1 inch overlap. Again cut off any excess. Now whip the splice for about 1 1/2 inches over the sheath lap. Stitch through the sheath and the Spectra cord over the entire 12 inch length, including through the whipping. Make two stitching passes, 90 degrees apart. The splice will require periodic inspection and re-whipping every 200 revolutions or so. DO NOT USE 6mm nylon in place of the Spectra cord. Such splices break at about 30 revolutions, while my Spectra cord splice still holds after about 400. A rack will work for the rappel device, but it will tend to wear the splice more quickly.
​
View attachment 42321
Click to expand...
That's coool. I've been doing some reading up on caving these days, managed to find 'Prusiking' by Robert Thrum too, awesome stuff and it all helps to understand why we got to where we are now. Manufacturers and Industry guidelines aside there is an awesomly huge world for us riggers to explore, as individuals. Love it !
 
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