need advise on setting up 4 or 5 to 1 pulley for felling trees & possible port-a-wra

[Tree Raptor]

Looking to purchase (set up) a 4 or 5 to 1 pulley set up for felling trees when needed. Looked at a few videos and went thru Wesspurs catalog. Right now we have 2 large blocks and using them but since I only have one ground man there are rare occasions where I need all the pulling I can get. Saw video on utube with 5:1 using Prussik Minding pulleys so that my ground man won't loose his efforts. This method uses a prussik to "hold" the pulled load. Not sure if this method is best or use some other type pulleys with other type "progress capture device".

don't mind spending good money to get the best but need to determine which is the best route to take. Not sure what the specific difference or purpose is between fiddle block pulleys and other types of pulleys. Just looking for a good straight forward 5:1 setup with a rope locking device. I don't know if some of progress capture devices do any damage to the rope vs using a friction prussik.

I have read that 1000 lbs would be the max anyone would want to pull on a tree so can I would assume that we would limit our pull rope to 1/2". My other 2 large CMI and aluminum pulleys take up to 5/8". Probably looking to use pull rope through pulleys and not a seperate rope as mentioned in the video.

Also this 5:1 pulley setup would be nice if I could also us it with the port-a-wrap if necessary.

Am including the youtube video link of the 5:1 that I saw so you can see his setup and other options that should be considered.

Tree Pulling Kit 5:1 Mechanical Advantage - YouTube (it's called Tree pulling kit 5:1 mechanical advantage)

Thanks

Tree Raptor

 

[Pelorus]

"I have read that 1000 lbs would be the max anyone would want to pull on a tree"

I'm really curious where you came across that figure.
On some bad leaners, even using multiples of 1000's still causes the ole sphincter to pucker up wondering if I should have taken more time to set a 2nd or 3rd line.

 

[Bearcreek]

I have read that 1000 lbs would be the max anyone would want to pull on a tree so can I would assume that we would limit our pull rope to 1/2". Tree Raptor

The pull required would vary widely depending on tree size, species, back lean, side lean, branch configuration, height of the tie in point, ratio of tree mass above the TIP to mass below, etc, etc. 1000 lbs. would often be sufficient but certainly not always.

 

[defensiblespace]

We have some big arse trees here in the sierras and the only thing i ever use is a vector pull or other forms of a 2:1 in conjunction with wedges. This requires minimal gear and it gets the job done every time. The trick is to get your attachment point high enough in the tree that you get good leverage.

 

[VA-Sawyer]

I took an older 150' PI climbing line and 2 of the dual pulleys from Sherrill PN 15217 and built a 5:1 system that I use quite a bit. I have a prussik on the pull line just on the other side of the pulley to hold the gain. I also use a pussik to attach it to the bull rope most of the time. Makes for quick setup with fast adjustments. On serious pulls I tie a BOAB in the bull rope and attach with heavy steel biner. I had one pull job where we used 5/8 bull rope, my 1/2" 5:1 and a set of fiddle blocks pulling on the pull line of my 5:1 to pull a tree back over center. Two of us pulling with 25:1 (plus friction) to get it moving in the right direction. Not the way I planned it ( amount of load ) , but it sure proved the concept and strength of setup.

I keep the whole setup (rigged pulleys with attached biners) in a milk crate for fast deployment. Grab correct size sling from sling bag and attach unit to tree. One biner is painted to indicate anchor end. Grab other end, hold capture prussik in released position and walk to desired position on bull rope. Put large prussik on bull rope and attach pulley with second biner. It took me longer to type the instructions than to set it up. When job is finished, pull tag end till pulleys are butted and feed tag into crate putting pulleys with biners in last.
When used with a porty, it does better if you use a pulley at base of work tree to redirect line to porty on another tree and attach 5:1 on horizontal run for lifting branches and such. (Not needed if just taking up a foot or two of slack above porty).

Total parts list: 2 pulleys, 2 rigging biners, 1 small prussik for gain capture, 1 heavier prussik for attaching rig to bull rope, 1 oval link for attaching rope spliced eye to pulley.

I have also used it for controlling tension on zipline, dragging logs up on tilt trailer, lifting feed roller off chipper for maintenance, and helping tug for stuck vehicle.

Rick

 

[2treeornot2tree]

The setup the guy built in the video is only a 4:1 system. If it was a 5:1 the rope he would be pulling on would be coming from the tree. First off, I wont want to have my pulley setup made out of the rope I am pulling with. If you need to readjust or lower, your screwed. I bought a fiddle block setup from baileys. The pulleys are alum, light weight, and has its own progress capture device. On big trees, I always use a 3 ton comalong with amsteel blue rope.

 

[TimberMcPherson]

I have a sling full of biners, pulleys, jumars etc. I just add bits as I need to make the pull stronger. But generally if we are doing anything serious, there is 5 tirfors waiting to be put to work.

 

[Tree Raptor]

follow up on 5:1 pulley setup

got some interesting and great info. Couple of questions that i forgot to ask in my first post.

Notice that everyone is using some sort of friction device knot to attached top pulley to pull line. Currently I just take the pull line quit a distance away from the tree i am using as the anchor tree to attached pulley and I just double the pull line and make a bowline knot (same as regular bowline except that the line is folded (doubled) over itself so that it can be undone easily.

Since I have not used a prussik friction on the pull line to anchor the first pulley I am concerned that "slippage" might be a problem whereas with tying a Bowline in the pull line making a large loop big enough to attached directly to the pulley sheave seams to be more positive and safe as their is no chance for slippage as top pulley is in the enclosed loop.

I assuming that the biners I intend to use for both ends connecting pulleys should be of the highest weight rating. I see that some are rated well over 10k and the price difference between the 5 & 6k and the 10 and above "K" is minimal so would guess go with the highest available.

Has anyone used any of the other "progress friction" devices out there (Gibb brand in Wespur) and how well to they work and do they wear the line in any way ? Again the reason that I am asking is just looking for the best, safest and quickest way to configure the 5:1 setup and I really don't care about cost.

 

[Tree Raptor]

5:1 pulley system (followup)

The setup the guy built in the video is only a 4:1 system. If it was a 5:1 the rope he would be pulling on would be coming from the tree. First off, I wont want to have my pulley setup made out of the rope I am pulling with. If you need to readjust or lower, your screwed. I bought a fiddle block setup from baileys. The pulleys are alum, light weight, and has its own progress capture device. On big trees, I always use a 3 ton comalong with amsteel blue rope.

I am not an expert on pulley ratio's as I am just getting into it now but the quote below came from a document on mechanical advantages found on the net and copying it below and if it is correct then it would be impossible for the setup on youtube to be a 4:1 as the tied off end is attached to the load.

"If the tied off end of the rope in a simple pulley system is attached to the load, the mechanical advantage will be an odd number: if it is on the anchor it will be an even number"

 

[VA-Sawyer]

Make the prussik loop out of rope at least one size smaller than the bull rope and slippage won't be a problem. You can always add another turn to the prussik for even more grip, if you want. The only reason I tie a BOAB in the bull rope on really hard pulls is concern about the strength of the prussik loop. My 'heavy' loop is 3/8" mountain climbing line rated over 5,000 lbs and is the weak link in the system. If I had one made from a good 1/2" rope, I could put a lot of pull on my 5/8 bull without concern.
And yes, that was a 5:1 in the video.
Rick

 

[squad143]

The setup the guy built in the video is only a 4:1 system. If it was a 5:1 the rope he would be pulling on would be coming from the tree.

I disagree.

To understand whether a Mechanical Advantage systems is odd or even:
If your line is terminated at your load, then your system is odd (1:1, 3:1, 5:1)
If your line is terminate at you anchor, then your system is even (2:1, 4:1, 6:1)
This is with your force away from the load.



Sorry, Tree Raptor, I did not see you previous post. The quoted statement you gave is correct.

 

[squad143]

I have the 5:1 kit from Sherrill. Petzl/SherrillTree Tree Pulling Kit : SherrillTree Tree Care Equipment Mine is an older version, but basically the same. Two double pulleys and a couple of eye to eye prussics.

I rarely use the pull rope as part of my mechanical advantage system. As others have pointed out, a pita if you have to readjust/reset.
I keep mine pre-rigged with 50' of rope (good for 10' of continous pull before needing a reset). I keep the system ready to go in a rope bag.

Using a mechanical device as your rope grab for your pull rope is quicker, but my main concern is the grab biting too much into the rope and desheathing it if loaded too much. Prussic tend to slip if overloaded, but not always. They can desheath the rope as well, so it helps to know your forces and equipment.

One main advantage of the fiddle block system, is that it has a very narrow profile as compared to the bulky double pulleys. I purchased the pulley kit because I could use the pulleys for other rigging applications.

just looking for the best, safest and quickest way to configure the 5:1 setup and I really don't care about cost.

You could just buy a GRCS, have a 44:1 MA and be done with it.

 

[squad143]

Usually if I'm doing a pull, I'll incorporate a port-a-wrap into the system. This way it holds the line while I have to reset my 5:1 MA system.

It is real handy, especially on Highlines as seen in this picture I took at an arborist seminar. The haul system was seperate and around the anchor tree as well, but removed before I could take the picture.

 

[CUCV]

Squad can you explain more why it is a pita to readjust/reset the Sherrill 5:1 while using just the pull line? I'm always trying to improve my setup. I built my own kit for $100 ie. had the biners, bought 2 prussic cords and 2 double pulleys (same rating as the Petzl just less cash) and find it very handy. I like the system because I don't have to bring an extra rope and I find it easy to readjust and reset. In theory I could pull an object to the anchor point the length of pull rope minus termination knot and say 5' to get 1' of pulley before the first reset.

I have the 5:1 kit from Sherrill. Petzl/SherrillTree Tree Pulling Kit : SherrillTree Tree Care Equipment Mine is an older version, but basically the same. Two double pulleys and a couple of eye to eye prussics.

I rarely use the pull rope as part of my mechanical advantage system. As others have pointed out, a pita if you have to readjust/reset.
I keep mine pre-rigged with 50' of rope (good for 10' of continous pull before needing a reset). I keep the system ready to go in a rope bag.

Using a mechanical device as your rope grab for your pull rope is quicker, but my main concern is the grab biting too much into the rope and desheathing it if loaded too much. Prussic tend to slip if overloaded, but not always. They can desheath the rope as well, so it helps to know your forces and equipment.

One main advantage of the fiddle block system, is that it has a very narrow profile as compared to the bulky double pulleys. I purchased the pulley kit because I could use the pulleys for other rigging applications.



You could just buy a GRCS, have a 44:1 MA and be done with it.

 

[Tree Pig]

Squad can you explain more why it is a pita to readjust/reset the Sherrill 5:1 while using just the pull line? I'm always trying to improve my setup. I built my own kit for $100 ie. had the biners, bought 2 prussic cords and 2 double pulleys (same rating as the Petzl just less cash) and find it very handy. I like the system because I don't have to bring an extra rope and I find it easy to readjust and reset. In theory I could pull an object to the anchor point the length of pull rope minus termination knot and say 5' to get 1' of pulley before the first reset.

what pulleys did you buy... I need some and that is like $200 less then buying most others I found... well thats if it fits 5/8 rope that is.

 

[squad143]

I rarely use the pull rope as part of my mechanical advantage system. As others have pointed out, a pita if you have to reset

Sorry, too much Christmas cheer.:redface:

In my mind, I was thinking of doing a raise (or tensioning) and then doing a lower.

If doing just a straight pull on dropping a tree, then yes the 5:1 will work on a single rope. Because of my system being pre-rigged, I rarely do it that way anymore.

 

[2treeornot2tree]

I disagree.

To understand whether a Mechanical Advantage systems is odd or even:
If your line is terminated at your load, then your system is odd (1:1, 3:1, 5:1)
If your line is terminate at you anchor, then your system is even (2:1, 4:1, 6:1)
This is with your force away from the load.



Sorry, Tree Raptor, I did not see you previous post. The quoted statement you gave is correct.

I disagree with you. I have built lots of pulley setups through the fire service. I have even built a 18:1 a couple times. What was shown on the video is a 4:1. If it was a 5:1 it would terminate at the anchor. It is just confusing because it is not a piggy backed system because he is using the main line. If this video was a 5:1 then my fiddle block would be a 5:1 and it is for sure a 4:1. As far as hooking to the rope. You can use a gibbs or something simular. I prefer to use 2 8mm prussiks on a 1/2" or 5/8" line. They will not slip and will not cut the line like a gibbs will if you shock load it. A 300 lb weight dropped 6' will cut a 1/2" 10,000 lb mbs rope with a gibbs. The same drop test with a double prusik just locks the prusiks and melted a little of the outer sheath of the rope. How you make the prusiks work is one of the prussik loops is shorter then the other. I like using a 5' piece, and a 6' piece of 8mm cord before tying your double fishermans knot. I can post pics if needed.

 

[the Aerialist]

I have it all ...

... On big trees, I always use a 3 ton comalong with amsteel blue rope.

Early on I bought a block and tackle setup but haven't used it in years, now for smaller stuff I have a couple of manual rope pullers that I use with 3 strand rope, but I also have a gas powered capstan winch that I can put on if I want a continuous pull. I also have probably the same 3 ton comealong that you have with about 30' of Amsteel blue. It came with a pulley mounted on a hook which I've never used, but wouldn't that double the force applied? I carry the 3 ton in the dump truck in case I have to pull it out from somewhere.

 

[sgreanbeans]

If you have blocks and a rescue pulley or even a micro, you can set up a block mechanical advantage system. No need to go buy stuff you already have. I have CMI stainless blocks and a few rescue pulleys, with tenex slings, whoppies and loopies, you have all you need. I don't use a friction hitch on the line, tie a slip not in the middle and clip a biner in. I have had the hitches slip on me, not good. You shouldn't need more than 2 pulleys to get good pulling power, if you need more than that, then you need to look at your notch and holding wood. I see guys all the time, get to about 20% holding wood, then back out and expect the guys to pull it over, they are pulling and pulling, tree is coming over,but dont let go. If the guy cut to a proper percentage, it would take very little effort to pull it over. My favorite is the guy the sticks his bar in, legs ready to run, hits the gas real quick, runs out and turns around to see the tree still standing! He will do this 2 or 3 times till he gets enough cut out. If the just committed, and stayed there and made sure they had about 10%, they could save alot of stress and energy. I also will throw a stick in the back cut to keep it from sitting back, if the guys let up a bit. If yall want I can have Bobby lee MAKE A VIDEO for ya!:biggrin:

 

[squad143]

then my fiddle block would be a 5:1 and it is for sure a 4:1.QUOTE]

Depending on how you rig your fiddle block, it could be a 4:1 or a 5:1.

Examine the pictue below:

Check this site for a good understanding of MA: Mechanical Engineering - Pulleys

Another site to check for comparing Tandem prussics to Gibbs ascenders: http://www.cmcrescue.com/Assets/reports/Ascenders.pdf

Id rather use a VT knot for connecting to the mainline rather than a prussic. I find the prussics difficult to loosen when heavily loaded as compared to the VT.

I stll go with my original conclusion that the video system is a 5:1. If you have info to show otherwise, I'm always interested in learning.