Can a dual sheeve pulley be used for two ddrt systems on a static line? One for the victim and one for me? Someone told me today that in the comps...this would never fly because it HAS to be on two separate systems...lame
I think it would work out just fine. Gear is rated high enough for it too be safe.
I'm probably mistaken, but if I remember Charlotte right, didn't Cormac run something where he had everything off one system? Not something like what you're talking about, but it was all off of his DdRT system. But like I said, I could have it all wrong. Maybe someone who knows Cormac's system could chime in?
2.4.2. states that "Contestants must lower the injured climber on the injured climber’s line or an approved line other than the contestant’s own that meets the requirements of rule 2.2.2. The contestant shall issue the audible warning, “stand clear,” before lowering the injured climber safely to the ground. (2009)"
I dont see a problem with this set up in this rule or any other that I read....
So long as its approved. Does not say anything about two lines off of one static line.
Actually I was saying "No , you would not be allowed to do what you are trying to do". If you are climbing off of a floating false crotch, then the line you are floating it off of is your climbing line. Therefore you could not also attache the injured to it. I can tell you that at ITCC it would not be allowed due to the potential for two person loads being transferred and quite possibly multiplied depending on your setup .
I don't think it would be allowed at the ITCC. I would have to see it to give a definitive answer. Is there anyway you can video it?
I'd like to see how the double pulley is anchored. I haven't run a double pulley with 2 different weights on each sheave. Will that offset the pulley?
I could see if you had it where it was a heavy duty dual sheave pulley. One thing to take into account would be if you're anchoring it as an srt system at the base of the tree you'd already be doubling the force on the TIP and now you're putting two sets of people weight on that TIP and multiplying it by two. I think it could be down with the proper rope and pulley combinations but for a competition I'd say it's not practical.
NFPA requires ALL of their gear to be rated for two person loads. do some reading and homework on your own to understand NFPA rescue systems. There is a lot to learn from how other rope rescue disciplines operate. Arborists can learn a lot from them. As much as they can learn from us.
The increased load on a ground-anchored ascent system can be mitigated easily but spiraling the rope down the trunk before anchoring. Go back to rigging loads before we had bollards and friction devices. Tree wraps have a long history in rigging.