Pulley saver for rigging?

Raven

Raven

Branched out member
Location
Northwoods
I love setting a pulley in a high point to rig limbs and small logs away from targets, but I hate going way back up there to retrieve the darn thing. Sometimes on a removal I'll go to within 8-10 feet of it then set a block and rig the spar down with my first pulley still in place(abandoned) for the groundies to retrieve once it gets to them.

I can't see the usefulness of BuckBlocks due to price and how do you cinch it onto a bare spar? The pulleysaver is the ticket here but can it handle a 200 - 500lb dynamic load repeatedly AND still be retrievable?

Sorry if this has been answered before but I'm just trying to save some energy up in the tops.
 
This is a very interesting question.

I don't think the PS is a good choice for two reasons:

1)
The pinto is unbelievably strong for it's size but it's certainly not designed for impact loading. If DMM would buy into this idea at all, I'm guessing you'd have to derate to very small drop pieces.

2)
The PS can get balky in releasing from a choking configurations. If the girthing line shifts/tilts downward, expanding the effective diameter of the spar, the resilient eye will be pulled into tension and you won't be able to release it from the ground. Makes me crazy when it happens. The single best way to induce the soft eye to go into "tension lock" is to hit it with an impluse load.


Instead, I'd think about a U-SAVER specifically built for rigging. Use two (2) small steel arborist rings and the large Pensafe rigging ring. Make it longer than normal so, for big drops, you can get your choke from an extra round turn on the stem, passing your rigging line through all three (3) rings. The tree (3) rings will deliver way more strength to your drop than a single pinto and you won't be concerned about holding the drop line "fair" thrugh the device. In fact, the bend radius might actually be better than the Pinto.

The "3-ring, wrapped" configuration will retrieve reliably but you won't be able to set it remotely.

However, you do have the option for a hanging TIP, with your rigging rope going through all three rings, set remotely and retrived remotely.

And for lighter drops, just pull the two rings through the Pensafe and you can choke without needing a round turn.


I'm pretty sure that the the US with rigging hardware would be a better choice but I'm completely ignorant about good choices for cordage in this application. I'm just guessing but I'd think probably something out of nylon or maybe even dynamic kernmantle to get some cushioning stretch, but I really don't know ...


I've been been really happy with the new Mini-US but I've never even thought about going the other way to a big, robust rigging configuration. Keep us posted.

OF
 
Oops! I need to correct myself right out of the gate ....

The Pensafe ring wouldn't be strong enough. Better the WM 2.5" ring, MBS ~25,000#. Since this isn't life support, you don't need it to be "marked". Also, it'll be better for bend radius.


Main line: 5/8" stable braid (16,300#)
Prussic: 10mm OP (33kN)
Small rings: small arborist, steel (30kN)
WM ring: 2.5" x 7/16", ~25,000# mbs

This combo should deliver the dropping strength about equal to an arborist block rated at 25,000# MBS.

Don't know about stretch.
Don't know about compatability with the prussic.

But it should be about 4-5x stronger than the original life support U-SAVER.

OF
 
Eric, attached is the ticket. Can be remotely set from the ground with throwline string, and retrieved like a ring & ring FS.
The inside one is made with a galvanized thimble and extra heavy duty galvanized thimble and 1/2" New England filament dacron (the easiet to make).
The middle one, my favorite, is two 1/2" pear links with round stock rod welded to act like a ring & ring FS, also with 1/2" filament dacron.
The outside one has 5/8's" pear links and 5/8's" filament dacron.
I like 3 strand because of it's durability for natural branch union rigging and ease of splicing.

I too would not use a pulley saver for rigging. I'm sure DMM would not recommend it for anything other than life support.
 

Attachments

  • 324154-100_0976-Copy.webp
    324154-100_0976-Copy.webp
    299.1 KB · Views: 257
Raven - Here is what I thought up when you posted this. This is NOT a working model - just something thrown together with what I had now. The ropes may not be compatible for the hitch, this that and the other may be wrong - but it just a thought on this.

For the "core" of the eye I used the rubber insert for a Cobra cable system - which is very sturdy IMO and should withstand many many load and unload cycles, the key is to get the right size diameter rope to insert the piece. Locking Brummell with a long bury. Prussic of suitable cord attached to pulley of your choice. Only thing I dont have is the capture end to make it retrievable - but I would think you could figure something out!

Again - just a thought...
 

Attachments

  • 324160-Riggingpulleysaver.webp
    324160-Riggingpulleysaver.webp
    179.1 KB · Views: 177
Thanks guys.

Norm those are nice but I already do use a ring and ring for light rigging - works great for light stuff you don't need to pick up.

I'm more interested in the pulley so I can lift and initiate swing away from a target - just like Jason has created, but will it work? Can you retrieve it J after successive loading? Maybe I'd have to use the ReTreever or pole hoke to reach out and grab it?

U-saver? with rings only or an actual pulley?

Hmm... many mysteries, many unanswerable questions. Experimenting shall ensue.
 
just use a loopie with a standard arb block. leave a little looser than normal. use pole saw to retrieve. as far as pulling and drifting the ring and ring works the coefficient of friction of steel and rope is approximately 0.3
the time saved trying to make a retrievable rigging set up that doesn't foul or knock your teeth out is almost point less for the work saved. read this naval paper on bollards it will explain friction loss at the rings better. remember the study was done in 1977 http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA036718
 
Eric - I can take it out tomorrow and drop some stuff on the loop to see what kind of abuse it can take. My gut is telling me that the rubber core will take some abuse.

my next thought would be to add something to the prussic to give it a greater diameter so it does not "cut" or "crease" into the rubber core yet remain flexible enough to perform properly. I would think something like the pipe insulator tubing or a swim noodle - cheap and easily replaceable?

I will give it some more thought tomorrow and see what I can come up with and maybe even see if works like I am thinking!

If you have time and want to swing by let me know - I'd love to do some testing!
 
[ QUOTE ]
Nice, Norm. I like the welded pears.
1. How you get them?
What does he do for choking? Make one long enough to wrap?
Tom

[/ QUOTE ]

1. I had our shop weld them in, after I cut them to length. They can't be choked, only basketed.


Eric, ever use a static retrievable false crotch? Can be set and retrieved from the ground, and you use an arb block. CMI's work best. The DMM's (impact block) would work even beter. I don't have any, yet.
 
Oh yeah, I read that in a book somewhere ;) (Art and Science of Practical Rigging)

Simple yet innovative, sometimes the answer is right in front of your nose and you never see it, thanks.

It could even be just a 10 - 20 foot pigtail left strategically for the climber to grab on his way out and not be one extra rope for the groundies to deal with. Ooh, how about a loopie with a loooong tail?
 
You must log in or register to reply here.

New threads New posts

Back
Top Bottom