Rappel trick - Save a cam?

[Blake]

I read of a trick to rappel from a cam, then get that cam back. Only works with U-stem models. Hitch a prusik to your rope next to the cam, and connect the prusik to the cam's trigger. Make sure there is copious amounts of slack. Pull your rope after you rappel, and you will pull the cam trigger, and your cam. Seems sketchy but theoretically possible. Anyone try it?

[Ireneo_Funes]

"Rappel" and "trick" are 2 words that don't always go together very well.

 

Why don't you just rap off a cam hook or a skyhook?

[Rad]

Cute.

So if you rappel 60m then your cam could fall from 60m to 120m. Would you use trust it again if it hit something toward the end of that fall?

[Cobra_Commander]

It wouldn't have to fall that far if you pulled it earlier.

[Weekend_Climberz]

That's what I would be afraid of...Having a mashed $60 piece of metal that is only useful for a doorstop afterwards. Not to mention the biners and whatnot used to hook the rope to the cam as well. Probably not a good idea to rap off of one piece of pro either. Take a sling, leave a sling.

[korup]

Yes, this is right up there with the magic-ice-screw-retrieval-trick (prusik on rope, then coil around screw as it turns in, rap, then pull rope and spin screw out). I suppose if I had a multipitch route to descend and only a single screw or cam, I might consider it if no other options existed. Otherwise, as Ireneo said, "neat trick" and "rap" should never be in the same sentence.

Is your life worth $80?

[Cobra_Commander]

Yes, this is right up there with the magic-ice-screw-retrieval-trick (prusik on rope, then coil around screw as it turns in, rap, then pull rope and spin screw out).

 

did someone actually pull this off, and have they ever heard of a v-thread

[Blake]

I'm not saying i've done it, would do it, endorse it, etc... just for the record.

[counterfeitfake]

I wonder how fast a cam is going when it's fallen 60m?

[Stavrogin]

I wonder how fast a cam is going when it's fallen 60m?

one of these

will solve that problem...

[Toast]

So something catches on the trigger end of the rope as you descend, then you get down real quick

[Ireneo_Funes]

but then, on the plus side, maybe the cam's fall will be cushioned by your corpse.

[Rad]

I wonder how fast a cam is going when it's fallen 60m?

 

distance fallen = 60m = A(t)(t)/2 where a = 9.8m/sec2, t = seconds falling.

 

solving, t = 3.5 seconds.

 

v = a(t) where v is velocity

 

ergo v = 34.3 m/sec or about 100 feet per second. Fast.

 

[Toast]

I think I'd be less concerned about the cam and more concerned about the biner. The biner is stiff all around and is probably going to take hard impacts all the way down. The cam has lots of springy/bendy stuff. It'd have to impact in just the right orientation for it to take the same hard impact.

 

Guys in Yosemite make a business collecting pro at the bottom of cliffs and peddling it at Camp 4. I might buy a cam for cheap cheap, but I don't think I'd buy a biner.

Edited October 25, 2005 by Toast

[korup]

did someone actually pull this off, and have they ever heard of a v-thread

 

Taking an ice class, one instructor showed us this setup. The other instructor then (wisely) stepped in and called him an idiot for even thinking about it, let alone teaching it in a class.

[crazyjizzy]

So what happens if the can will not pop? Now your rope is stuck 200' up, to a possibily shitty cam. Do you have your partner jug on up?

[layton]

I read the same thing about getting t-slotted ice axes or pickets back via a prussick. Hmmmm..

option #1 (the more likely option)=it doesn't work and you gotta jug

option #2 = it does work and you have heavy sharp things falling towards you at 9.8 meters/second.

 

pretty sweet!

[bigwalling]

That sounds fucking dicey to even me!

 

...man dies while jugging, rope was stuck with prussik attached to cam. It is assumed the man was jugging the line and his "trick" setup finally worked.

[EWolfe]

I NEVER rap off just one piece.

 

Safer and cheaper to find a hex/nut/tricam combo and leave a coupla biners AND INSURE LIFE.

 

[EWolfe]

Gawd. I sound like an insurance salesman.

[Blake]

I NEVER rap off just one piece.

 

Safer and cheaper to find a hex/nut/tricam combo and leave a coupla biners AND INSURE LIFE.

 

 

what's the difference between lowering and rappeling off of one piece though?

[Ireneo_Funes]

Lowering off of one piece is also a bad idea.

 

I think I heard somewhere that lowering puts more force on the anchor than rappelling. Maybe one of the physics experts can elucidate it for us.

[cluck]

I can appreciate this trick as a cool idea. And I bet it might even work.... some of the time. But like other's have said - it's waaaay to risky to be practical.

[iain]

I think I heard somewhere that lowering puts more force on the anchor than rappelling. Maybe one of the physics experts can elucidate it for us.

 

it's a crappy 2:1 pulley on the anchor.

[selkirk]

Lowering off of one piece is also a bad idea.

 

I think I heard somewhere that lowering puts more force on the anchor than rappelling. Maybe one of the physics experts can elucidate it for us.

 

As memory serves you lowering increases the force on the anchor by a factor of 1.6 (when compared to a simple rap).

Rapping has 1/2 your bodyweight on each strand.

Lowering has your bodyweight on each of the strands (roughly).