catbirdseat Posted January 25, 2004 Share Posted January 25, 2004 Here's another one of those hairbrained catbirdseat ideas. Design a 60 m rope that is 10.5 mm in diameter for 10 m on each end, but the middle 40 m is 9 mm diameter. The reasoning goes like this. The 9 mm is plenty strong provided you don't take a high fall factor fall on it. When are you going to take a high fall factor fall? -when you are first leading out from the belay. So you can climb 5 meters and fall on your first piece (FF 1) or climb 10 meters and fall on the belay (FF 2) and be held by nice fat rope. After that, the rope tapers down to 9 mm and you don't need it fat because any falls will be on successively lower fall factors. Why make it fat on each end?- so that you don't have to worry about which end to lead on. Total weight savings over a 10.5 x 60 m rope would be 24% or about 3.5 lbs. Probably it's not worth the technical difficulty of engineering such a rope. Back in my sailing days, we used to buy skinny kevlar cored ropes for spinnaker sheets and then pull the core out of larger ropes and slide part of the kevlar rope inside the cover so that half of it was larger diameter for better handling, while the other half was not covered so it would be super light and not weigh down the spinnaker in light airs. Quote Link to comment Share on other sites More sharing options...
Jake Posted January 25, 2004 Author Share Posted January 25, 2004 Now that is a good idea. I have no idea what the engineering would be on that or if it would actually work - it seems like it would - but good idea anyway. Quote Link to comment Share on other sites More sharing options...
scrambled_legs Posted January 25, 2004 Share Posted January 25, 2004 Ay, Captain... You might be on to something... Hoist the main sail!! Quote Link to comment Share on other sites More sharing options...
David Yount Posted January 25, 2004 Share Posted January 25, 2004 CBS, sweet idea. Currently science fiction, maybe fact in the future. Kinda like double butted bicycle spokes 14gauge-15gauge-14gauge. I like 9.small millimeter 70-meter for connecting pitches, coupled with a 7.4mm twin for full length raps. Thread the thick line through the anchor, pull the thin line. If the thick line gets stuck during the pull I can lead (or continue rapping) on the twin by doubling it. Well, I don't mind the weight; though most would rather fall into a deep crevasse with a broken leg, alone. I think 100-meter lines are for doubling and using as double rope technique. When rapping you dont' have any joining knot; smooth...... --David. Quote Link to comment Share on other sites More sharing options...
EWolfe Posted January 25, 2004 Share Posted January 25, 2004 Here's another one of those hairbrained catbirdseat ideas. Design a 60 m rope that is 10.5 mm in diameter for 10 m on each end, but the middle 40 m is 9 mm diameter. The reasoning goes like this. The 9 mm is plenty strong provided you don't take a high fall factor fall on it. When are you going to take a high fall factor fall? -when you are first leading out from the belay. So you can climb 5 meters and fall on your first piece (FF 1) or climb 10 meters and fall on the belay (FF 2) and be held by nice fat rope. After that, the rope tapers down to 9 mm and you don't need it fat because any falls will be on successively lower fall factors. Why make it fat on each end?- so that you don't have to worry about which end to lead on. Hey, Genius? How are you going to achieve continuous core threading in your weave? Quote Link to comment Share on other sites More sharing options...
scrambled_legs Posted January 25, 2004 Share Posted January 25, 2004 Hey, Genius? How are you going to achieve continuous core threading in your weave? It might be pretty easy actually. Just ask Erian Armanios and Stefan Dancila. They're coming up with some pretty wacked ideas that might just make our ropes as outdated as hemp. www.bizjournals.com/atlanta/stories/2000/09/18/focus22.html It all depends on how the manufactures determine the core thread size now. The core threads are simply Nylon (a man made material)and they have a machine which creates these 50m long fibers. Now correct me if I'm wrong, but I think that each individual strand is actually different in size for a 5mm rope vs. a 12mm. I don't think a 12mm has that much more strands but rather thicker strands of nylon being wound to comprise of the larger nylon core. In order to make a rope with thicker ends, you simply make each (man-made) nylon strand thicker at both end sections. Adjust the nylon strand machine to pump out a 10.5mm strand for the start of the rope which then reduces to a 9mm width strand for the middle section but fattens back up to a 10.5mm strand width for the end. The machine can already adjust the width of the nylon strands. It would just be adjusting it while producing each strand. Each strand still runs from one end of the rope to the other, yet the thicker width at the ends would produce a larger/stronger rope core at the ends where the higher fall factors occur. Oh... and don't call me genious Quote Link to comment Share on other sites More sharing options...
chriss Posted January 26, 2004 Share Posted January 26, 2004 The different diameter thing has already been done. A french company, Rivory Joanny (sp?) did this in the late 80s. It was intended as a sport rope. Didn't catch on. Sorry, it did sound like a good idea then too. chriss Quote Link to comment Share on other sites More sharing options...
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