I should know this but... Well, When using a tripod, we usually use a winch, or a put our MA away from the tripod and just use the tripod pulley's as change of direction as in image below.
I feel dumb for asking, but, if your using a 4 to 1 pulley with a cam, how would you perform the lowering? See image below. Is a lowering device not needed in this case? Does the 4:1 MA allow enough descent control?
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Thread: 4 to 1 on tripod
02-11-2013, 06:23 AM #1
4 to 1 on tripod
02-11-2013, 01:21 PM #2
I would say you still need a lowering device/prussik in there. Yes you can control decent but theres no "stop" feature if there was an issue.
We run the same setup as the bottom picture for the most part, just throw in a change of direction and a couple prussik in there and it would look like ours 99.99% of the time.
02-11-2013, 03:58 PM #3
if you are using the CSR setup from CMC (as pictured) then you just release the cam with the little cord while holding resistance with the free end of the rope. it takes very little to hold back the lower as there is not much tension at that point in the system. CMC recommends that you have a separate person operate the cord from the person holding the rope.
there is probably a belay system independent of the tripod somewhere here as well i'm guessing.
mikeMy opinions posted here are my own and not representative of my employer or my IAFF local.
02-11-2013, 04:46 PM #4
02-11-2013, 04:49 PM #5
02-11-2013, 05:10 PM #6
02-11-2013, 05:35 PM #7
Strange. I edit the post with the CSR pulley to use a smaller image, but even after deleting it, the large image still shows up. Sorry, bout that.
02-20-2013, 09:36 PM #8
you could also construct your own 4:1 with a PCD.. (progress capturing device) which most of the time is just going to be a 3 wrap prusiks. put the prusiks on the rope directly behind the haul rope. THen carabiner, sling and attach it somewhere at the top of your tripod. the farther down you put the prusiks the better (so someone can mind it) which means you'll have to have a decent size piece of webbing. also, Your top pulley would have to be a PMP to mind the prusiks when hauling back up."....train as if your life depends on it, because one day it could.."
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Tillerman..... The best job in the FD!!!
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By ProgressiveRescue in forum Specialized RescueReplies: 30Last Post: 03-10-2013, 08:06 AM