Does it make more sense to core out the V thread holes slightly pointing downwards (or in the direction of pull) to mitigate any shearing of the cordallette on the holes when loaded? Similar to the downward angling of screws when placing them on lead?
A double fisherman's on the thread is a bit time consuming and tricky with cold hands or gloves. Have you considered a simple overhand as used for twin rope abseil, with a second separate overhand next to it just to be sure. Quick, easier to tie with gloves, easy to inspect.
You could use an overhand aka "european death knot" but keep in mind it weakens polyamide cord's breaking strength by ~30%. dyneema or kevlar cord would even be weakened ~70%! A triple fishermans on the other hand doesnt weaken poylamide at all and dyneema/kevlar around 25%.
I understand the concern that your rope may freeze and get stuck in wet ice, but please explain the concern in negative temps? (And do you mean negative C or F?) And please explain your backup screw and draw- is it for everyone except the last one to rappel who removes it and brings it down? (My guess and what I've read elsewhere.) Thanks!
Thanks, Andrew! Got it- if the ice is wet but temps are or will be freezing, the rope could freeze in the ice and make for a bad day. Makes perfect sense, not sure why I didn't get it first time around. I probably shouldn't post questions late at night!
Is the reason you're not just using an ice screw by itself because the screw is not strong when used vertically against the direction it went in? Or is it the efficiency of cleanup when the last guy rappels and can take the gear with them?
It's so you're not leaving gear behind. Ice screws are expensive. The screw acts as a backup for the first rappel. After the first person gets down and the v-thread has proven itself strong, the last person will rappel off the v-thread alone and remove the screw.
The point of the backup is to not be weighted unless the v-thread rips out. In that case, the ice screw should save you. You let the heaviest climber abseil first. If there are no problems with the v-thread the second lighter climber can take out the backup and abseil on the thread as well, thus only leaving the v-thread and not the expensive ice screws. Hope that helps :)
Who cleans the backup ice screw?... the last person to rap? ... is it a backup for everyone except the last person out?... or is this an expensive sport that you just leave expensive ice screws behind?!?
The last person to rap takes it with them. The idea being that the anchor is strong enough if it held the first people. Or if you're rapping alone you can check the strength of the anchor while the ice screw is in there and then take it out before actually descending
Decades of use says yes, for sure. When you make a good one and the ice is HARD, you'll have no doubt. The loads on it should be minimal as well. There's also the beauty of the heavier of the two climbers gets to test it while backed up. The second person then gets to examine the holes and surrounding area for fracturing or other changes in the ice once the first climber has gone down to the next anchor or the ground.
The V-tread is make with two holes, one next to other and not upon or under it. Why don't follow the same logic that we use when place ice bolt for an anchor?
Does it make more sense to core out the V thread holes slightly pointing downwards (or in the direction of pull) to mitigate any shearing of the cordallette on the holes when loaded? Similar to the downward angling of screws when placing them on lead?
A double fisherman's on the thread is a bit time consuming and tricky with cold hands or gloves. Have you considered a simple overhand as used for twin rope abseil, with a second separate overhand next to it just to be sure. Quick, easier to tie with gloves, easy to inspect.
You could use an overhand aka "european death knot" but keep in mind it weakens polyamide cord's breaking strength by ~30%. dyneema or kevlar cord would even be weakened ~70%!
A triple fishermans on the other hand doesnt weaken poylamide at all and dyneema/kevlar around 25%.
these are great. keep up the good work
I'd love to get into this but I live in Arizona. The only ice is in the freezer.
I moved from Arizona to Alaska a year ago. Best thing i've ever done.
I understand the concern that your rope may freeze and get stuck in wet ice, but please explain the concern in negative temps? (And do you mean negative C or F?) And please explain your backup screw and draw- is it for everyone except the last one to rappel who removes it and brings it down? (My guess and what I've read elsewhere.) Thanks!
I'm pretty sure he meant Fahrenheit as positive Celsius would be wet ice as it is melting and he mentioned that separately.
Thanks, Andrew! Got it- if the ice is wet but temps are or will be freezing, the rope could freeze in the ice and make for a bad day.
Makes perfect sense, not sure why I didn't get it first time around. I probably shouldn't post questions late at night!
Is the reason you're not just using an ice screw by itself because the screw is not strong when used vertically against the direction it went in? Or is it the efficiency of cleanup when the last guy rappels and can take the gear with them?
It's so you're not leaving gear behind. Ice screws are expensive. The screw acts as a backup for the first rappel. After the first person gets down and the v-thread has proven itself strong, the last person will rappel off the v-thread alone and remove the screw.
interesting that locking draw
Who makes the tool you use for the 0-thread? I've never seen one like that, but I like the idea of not hooking my climbing rope.
its called the j snare
www.jsnare.com/
What is the minimum ice screw length to build a v-thread ???
So you backup the anchor and then weight the v- thread then remove the backup before repelling? Or do you sacrifice your gear and leave the screw?
The point of the backup is to not be weighted unless the v-thread rips out. In that case, the ice screw should save you. You let the heaviest climber abseil first. If there are no problems with the v-thread the second lighter climber can take out the backup and abseil on the thread as well, thus only leaving the v-thread and not the expensive ice screws. Hope that helps :)
This is called Abalakov thread
wow you have a middle of the middle mark mark! hah
Who cleans the backup ice screw?... the last person to rap? ... is it a backup for everyone except the last person out?... or is this an expensive sport that you just leave expensive ice screws behind?!?
The last person to rap takes it with them. The idea being that the anchor is strong enough if it held the first people. Or if you're rapping alone you can check the strength of the anchor while the ice screw is in there and then take it out before actually descending
Is it trust worthy.?? I have never used.
Decades of use says yes, for sure. When you make a good one and the ice is HARD, you'll have no doubt. The loads on it should be minimal as well. There's also the beauty of the heavier of the two climbers gets to test it while backed up. The second person then gets to examine the holes and surrounding area for fracturing or other changes in the ice once the first climber has gone down to the next anchor or the ground.
The V-tread is make with two holes, one next to other and not upon or under it. Why don't follow the same logic that we use when place ice bolt for an anchor?
Another comment section expert.