- Location
- Saskatchewan
I have some pulleys and a rigging prussic. I setup a 5:1. Looking for suggestions for which leg of the rope to put the prussic on to capture progress.
Where do you put your prussic for progress capture on a 5:1 MA system?
- Thread starter TreeManMyk
- Start date
Zebco Kid
Branched out member
- Location
- Ashland, Oregon
TreeManMyk,
It looks like there might be more than one location to place your prussic.
It looks like there might be more than one location to place your prussic.
Reach
Been here much more than a while
- Location
- Atglen, PA
I would personally run the prussic on the leg of rope you are pulling, and attach it to the last pulley the rope runs through, so that the prussic is easily accessible and can be easily removed if necessary.
Stumpsprouts
Been here much more than a while
- Location
- Asheville
Ditto. That works great. Prusik is only getting the amount of force you can pull, if you put a prusik at the load end of the system, it would be getting 3, 5, etc times the force of your pull, harder to disengage. Also adds a lot more friction to your pull when it’s at the load end.
Barc Buster
Branched out member
- Location
- The land shaped like a hand
This is how I’ve always done it too and for the reason mentioned.
- Location
- Saskatchewan
Cool..Thanks guys!
Barc Buster
Branched out member
- Location
- The land shaped like a hand
Should also point out if the pic zebcokid provided makes the three previous statements confusing it’s because the pic is depicting a load below lifting scenario vs. a load above scenario.
It should be flipped with an extra block, rigging ring, aerial friction device etc. above the load for the most common lowering scenario in tree work. I bet @TheTreeSpyder will be along shortly with one of his excellent illustrations.
For rescue systems, we always put tandem prusiks on the leg of rope going to the load. (As shown in the @Zebco Kid diagram.) That allows the MA system to easily be modified while in use. If you need to release the prusiks, with a short haul, you have MA pulling the prusiks into the sideplates of the prusik minding pulley, aiding their release.
At least with tree work, it's unusual for me to need to release the tandem prusiks for lowering/slacking the system. I'm generally just pulling until the tree comes over.
At least with tree work, it's unusual for me to need to release the tandem prusiks for lowering/slacking the system. I'm generally just pulling until the tree comes over.
TheTreeSpyder
Branched out member
- Location
- Florida>>> USA
i think @Zebco Kid showed pretty well w/red & yellow upper Prusiks, always have the Prusiks on the Load side of any pulley. Cheek plates or other contrivance (added padlock around rope and Prusik quickly 1x to some one else's existing system)to groom/comb/serve Prusik forward and not get jammed in machinery (pulley, Porty etc.).
i'd usually not have Prusik directly against the raw Load usually, especially if can be over 5-700#.
This can be for safety and 'ratchetting' of rest holds, or then impacts etc.
1 Prusik to take the Load at that point and 1 as clean-up and backup.
Many, things are of this bulk stop and then bow to nothing 100% efficient with another stop, that is also a keeper of the first and safety backup as well. Kinda like cleaning or sanding etc. of bulk hit and fine finish to me in some ways tho.
.
But for adjustment @Dan Cobb suggests for more flexibility in adjusting power/speed tradeoffs for varying functions and load ranges for varied not single usage; (always seemed the rescue pix of Prusik on the Load side of final anchor pulley as he says) , i would '2hand'/double input into the system (or have a quick zRig to add, or improvise 2 or 3x with tail).
'2hand'/double input where can instead of input of effort up to body weight,
input Bodyweight + Effort + equal & opposite of Effort (kind of a morph i found of DdRT; after sitting in DdRT an embarrassingly long time before seeing this). The 2 part input (Bodyweight & Effort) can hold Load at bay with 1 input and impact with other, or both in concert, or impact start with 1 and maintain with it and add other follow thru
>>much more flexible system to varying strategies w/less rope and pulleys.
The strategy of inventorying and collecting all possible forces of Bodyweight + Effort + equal & opposite of Effort to then leverage against Load i distilled it further down to anytime can connive a 1st class lever of pulley in flexible levers/ropes or see-saw in rigid levers and get Bodyweight to work directly or indirectly against the Load and then add Effort and use the 1st class lever system (one with pivot between input and output, not on end where input and output are next to each other) to capture and return back to service against Load the escaping equal & opposite Effort that is normal byproduct of Effort, only now collected and deployed to service against Load....
Systematically one of the greatest things i found for simply increasing output, with existing tools, shituation etc. by using the usually unrealized autonomous responses if equal & opposite of Effort and also Bodyweight as a separate input and not just a limiter to single input of effort.
Note how at least 1 Effort part goes directly, unfiltered against Load side of pivot in each case.
If the last log pic is a log in air, it's own CoG then becomes the pivot of most loaded point, just like 2/1 in pulley as pivot point receiving both inputs to apex.
In fancier terms we are just 'conserving' most/all forces have to target against load as inputs to then be leveraged.
.
This is aberrant to normal thinking (guess no surprise thar) that if single pulley MUST be on/against/output to Load/dynamic position to increase power or against input/dynamic Effort position to increase speed. Single pulley on anchor/static position as redirect only. For here can get more power from single pulley on anchor/static !
Just as do in DdRT over own self; of 1 input affecting 2 pulls against Load(self)!!
DdRT presents Effort and equal & opposite against Load(self) by capturing equal & opposite running away from work around to also helping. Strategy shown takes that and adds self/bodyweight that was Load to know be in concert with the Effort + equal & opposite of Effort against a now other Load.
.
There will be reduction in output potential from frictions, so 5:1 may return 4.3x, but not of any inputs directly against Load as can do here. But, 5:1 rig will always take 5x Distance input vs. output even if force return is 3.3x w/higher frictions.
i'd usually not have Prusik directly against the raw Load usually, especially if can be over 5-700#.
This can be for safety and 'ratchetting' of rest holds, or then impacts etc.
1 Prusik to take the Load at that point and 1 as clean-up and backup.
Many, things are of this bulk stop and then bow to nothing 100% efficient with another stop, that is also a keeper of the first and safety backup as well. Kinda like cleaning or sanding etc. of bulk hit and fine finish to me in some ways tho.
.
But for adjustment @Dan Cobb suggests for more flexibility in adjusting power/speed tradeoffs for varying functions and load ranges for varied not single usage; (always seemed the rescue pix of Prusik on the Load side of final anchor pulley as he says) , i would '2hand'/double input into the system (or have a quick zRig to add, or improvise 2 or 3x with tail).
'2hand'/double input where can instead of input of effort up to body weight,
input Bodyweight + Effort + equal & opposite of Effort (kind of a morph i found of DdRT; after sitting in DdRT an embarrassingly long time before seeing this). The 2 part input (Bodyweight & Effort) can hold Load at bay with 1 input and impact with other, or both in concert, or impact start with 1 and maintain with it and add other follow thru
>>much more flexible system to varying strategies w/less rope and pulleys.
The strategy of inventorying and collecting all possible forces of Bodyweight + Effort + equal & opposite of Effort to then leverage against Load i distilled it further down to anytime can connive a 1st class lever of pulley in flexible levers/ropes or see-saw in rigid levers and get Bodyweight to work directly or indirectly against the Load and then add Effort and use the 1st class lever system (one with pivot between input and output, not on end where input and output are next to each other) to capture and return back to service against Load the escaping equal & opposite Effort that is normal byproduct of Effort, only now collected and deployed to service against Load....
Systematically one of the greatest things i found for simply increasing output, with existing tools, shituation etc. by using the usually unrealized autonomous responses if equal & opposite of Effort and also Bodyweight as a separate input and not just a limiter to single input of effort.
Note how at least 1 Effort part goes directly, unfiltered against Load side of pivot in each case.
If the last log pic is a log in air, it's own CoG then becomes the pivot of most loaded point, just like 2/1 in pulley as pivot point receiving both inputs to apex.
In fancier terms we are just 'conserving' most/all forces have to target against load as inputs to then be leveraged.
.
This is aberrant to normal thinking (guess no surprise thar) that if single pulley MUST be on/against/output to Load/dynamic position to increase power or against input/dynamic Effort position to increase speed. Single pulley on anchor/static position as redirect only. For here can get more power from single pulley on anchor/static !
Just as do in DdRT over own self; of 1 input affecting 2 pulls against Load(self)!!
DdRT presents Effort and equal & opposite against Load(self) by capturing equal & opposite running away from work around to also helping. Strategy shown takes that and adds self/bodyweight that was Load to know be in concert with the Effort + equal & opposite of Effort against a now other Load.
.
There will be reduction in output potential from frictions, so 5:1 may return 4.3x, but not of any inputs directly against Load as can do here. But, 5:1 rig will always take 5x Distance input vs. output even if force return is 3.3x w/higher frictions.
evo
Been here much more than a while
- Location
- My Island, WA
It depends on the application. For simple progress capture prussic on the first pulley near the operator. For the most control (on/off) the prussic goes on the first pulley on the anchor keeping the loading ‘light’ and in reach.
If a critical load and a prussic backup if system failure is needed, then the last pulley either on the load end or the last pulley on load leg at the anchor
If a critical load and a prussic backup if system failure is needed, then the last pulley either on the load end or the last pulley on load leg at the anchor
dspacio
Branched out member
- Location
- Narragansett Bay
it's amazing when something I am just wondering about since Wednesday appears on the Buzz the next time I check in, with a dozen replies already chalked.
