Friction Saver Prussik

[tshanefreeman]

Just wondering what the purpose of the small spliced loop found adjacent to the eye-to-eye prussik was?

When I make the twist like the attached picture shows, I'm finding that it doesn't bite down on the friction saver! Therefore, I question it's purpose. I also do not believe that the problem is due to my friction saver..............it was previously also purchased from Sherrill.

Any explanation would be appreciated.

 

[Burnham]

The loop serves as a slack tender. And not particularly well, IMO.

 

[Tom Dunlap]

I've never liked that setup. It seems really odd to take round rope and bend it around a flat webbing. Doesn't seem as effecient as possible.

In my progression through false crotches, I made up a nice adjustable FC that functions a lot like that but is much cheaper.

Eye splice a piece of climbing line or any acceptable line. You could tie an eye knot in the end too if splicing isn't in your skill kit. Clip a biner into the eye. Much more flexible than being stuck with only a ring. Then add your favorite friction hitch. You can use a smaller biner or screw link but it is more effecient to use a small pulley. Add a secure stopper knot to the end of the FC line and your're set to jet. I'd bet that most climbers have all of the parts to make this up in their kit right now. You could make up several FC lines out of spare pieces of rope. Think of all the other gear you can buy with the money you save!

Tom

 

[jblimbwalker]

Before I bought mine I also wondered what the supposed 'slack tender' was. I figured it was some kinda back up if the prussic loosened up I agree with Burnham in that it doesn't function well for tending slack. I don't use it, just hangs there. I also agree with Tom D. on making your own. Check thread entitled 'New False Crotch Design', by Maas.

 

[tshanefreeman]

Reply to Tom Dunlap

This is a new piece of equipment that I added to my bag of goodies this past summer. However, I just had a chance to use it for the first time this past week.

The idea of having a self-adjusting attachment point sparked interest in me when I considered the results of extreme barber-chairing. The Friction Saver Prussik device was never intended to be part of my everyday gear..................just to be there if I ever felt the need.

Unless I'm not understanding your FC device, I don't believe that your's would automatically loosen in times of need! If I'm wrong...........please correct me.

 

[Tom Dunlap]

Shane,

the mechanics of mine and the store bought one are the same. The home made is cheaper, lighter and can be made to any length. With the addition of a key chain biner under the friction hitch it can also have the slack tending capabilitiy of the store bought.

Tom

 

[rborist1]

:Eye:

 

[ramanujan]

For the FC-as-a-lanyard setup to let line out if the spar splits you must be tied into the FC setup with your climbing system. See the link above. Then, if the spar splits, the idea is that the ring or biner above your friction hitch will act as your hand does on your hitch and let line out so that you're not sucked into the spar.


I've never used the setup but I think it would only be something I would employ in times when the need for precaution overrode the hassle of it.

 

[John Paul Sanborn]

Another method i've seen by some top climbers I respect, is to gitrth hitch the climbing line to the spar, and attatch the tress cord to the center D.

So one is in effect working SRT... FWIW.

this used as backup for the flipline while blocking/chunking.

 

[Matt Follett]

John,

I think what your talking about is how I block down, but I have some concerns about it and am interested in listening to concerns and comments...

I climb with a captive eye on the standing end of my line... and as I block down I cinch my line with the biner... gate up so that if I slip and load it the load will not be against the gate...

I use a Distel 99.9% of the time and it works not to bad, once the block is off, I decend on the distel to the next notch point, set everythiing up then slack the climbing line off and the rope slides down (provided there's no stubs, crotches etc, to foul the system... It seems to work well but I often wonder about the now double load (single line) on the distel, (or blake or whatever one uses) and the effect and impact would have if I slipped...

My belief is that if the stem split, the biner would push the knot along, but hey it hasn't happened (thankfully) so I am only speculating on the case.

Thanks for your imput

oh and if this is some old antiquated technique... pardon me and my not so up to date climbing, remember 'keep it simple for stoopid', the guys always tell me, he he

 

[John Paul Sanborn]

All these methods are speculation, except what would happen if on a conventional splitail system witha barberschair.

I don't think nayone wants to play ttest pilot for the situation either.

 

[Matt Follett]

This poses a question...

Do we know of a incedent where the lower portion of the spare split, particularily in the 'big wood' senario we are concerned with?
And injured the climber who was pulled in.

Would there not have to be incredible force on a tipping spar... with a notch cut at an angle which would close the too soon?

I think my greater concern would be the tired climber who set the climbing line into the rigging, and subsequently got yanked as things were 'caught'

just me pondering...

 

[ramanujan]

Matt I've often used the same system, tho I've never thought of the biner possibly pushing the hitch down in the event of the spar splitting.

I've often seen hardwood spars (most notably red alder) split slighty, never more than an inch or two, as i'm chunking them down. We refer to it as 'checking,' it makes unnerving vibrations in your gaffs.

I think maybe the most probable instance of a spar splitting apart is in a tree that has already been seriously damaged by something, or rotting, and is already split and leaning. But I would hope the plan to deal with a seriously hazardous tree includes more than a lanyard with line-letting capablities, but no doubt a worthy precaution when it's called for.

 

[Mahk]

Originally posted by rborist1
Tom,

Pic please!

This is a pic of one that is similar to Tom's. I opted for rings rather ethan a carabiner/micro-pulley setup. There is no slack tender because, regardless of the size of the tree, the prusik is always within arms length. The screw link is for retrieval (see next two attachments).

Mahk

 

[Mahk]

I had problems getting the pic to attach. It is on the post below that says:

"The rope version of the Friction Saver Prusik (FSP) set up on a tree."

The climbing hitch should be on the leg of the climbing line that goes through the small ring (left side in this instance).

The scenario that is presented in the Sherrill catalogue is that, if the tree were to split, the climbing hitch (not pictured, but, to repeat, in this instance it would be on the left leg of the orange line) would hit the small ring, which would work like a slack tender and feed the climbing line as the piece splits so the climber does not get crunched. But, in practice, there are several problems with this. If you set the FSP on the base of a tree and try to create that scenario by pulling on the backside of the lanyard things don't work well. The climbing line quickly becomes doubled and the small ring can move away from the climbing hitch (as in the pic in the above (first?) post taken from the Sherrill catalogue p. 20). If the whole system does work as it is 'supposed to' i.e. the lanyard increases in size as the piece splits, then, once the piece is on the ground the climber is left in the tree with a lanyard that is now as large as the distance to the ground (the distance the piece fell and opened the lanyard). This also assumes that the climber used only one lanyard--the Friction Saver Prusik lanyard, as in the pic above. If the climber had used a second lanyard (which, according to ANSI we are supposed to do when using a chain saw) then that would also have to be a Friction Saver Prusik lanyard. If it were a standard lanyard then that lanyard would suck the climber into the tree. The better option would be to have the second tie-in point be a climbing line in another tree, but that is not mentioned in this context, nor is it always possible. If that is an option and there is a real danger that the removal tree will split, then the climber could use a very short rope (the orange rope in my pic) with no knot so that if the tree splits the orange rope would, hopefully, quickly run through the climbing hitch and the small ringof the FSP. People should be aware of these drawbacks and not use the FSP thinking that thewy will be completely protected and free from danger.

Having said all this I do think this is a very helpful setup for big, stubby trees. I have tried the 'running bowline' method and girth hitching the climbing line with a carabiner, but had problems with the rope getting hung up when I try to bring the system down. With the FSP system retrieval is much easier (see next pic).

Mahk

 

[Mahk]

The pic that goes with this is attached to the post below that says:

"Retrieving the FSP."

The screw link will pass through the big ring, catch on the smaller ring and the whole system will fall to the climber. With the running bowline and carabiner/girth hitch systems the climbing line forms a loop and tends to get caught on stubs. The climber also needs a backup for their climbing hitch or they need to use a descender because they are essentially coming down on a single rope. When the FSP is removed there is just a rope end (actually the big ring) that has to fall so there is much less chance of getting it stuck. (One word of caution. Make sure that the screw link will pass through the big ring even when it is girth-hitched to the eye splice. The scew link that I initially used for this would pass freely through the big ring, but not through the portion of the big ring where the rope was girth-hitched.) Also one can climb down (or up) with the traditional doubled rope and climbing hitch. There is no need for a descender.

Once retrieved, the big ring is thrown around the trunk just as one would do with the end of the climbing line or lanyard. The screw link can be left in the eye when the climber clips the eye splice back to their saddle. The screw link does not interfere with the girth hitch on the carabiner.

Mahk

 

[Mahk]

The rope version of the Friction Saver Prusik (FSP) set up on a tree.

 

[Mahk]

Retrieving the FSP.

Sorry it took so long to get the attachments posted.

Mahk

 

[ramanujan]

thanks for the informative pics Mahk. good to see technical stuff working on the jobsite.

 

[Mahk]

Rocky;

The reason for the girth hitch (and for an eye splice at each end of the FS) is that I have used that particular rope for various applications.

I had that same problem with my first screwlink which is why I added the 'word of caution' in one of the above posts. The girth hitch doesn't make the rope twice as thick in the large ring, but twice as wide (actually a little more than twice as wide). When trying to run the link through the ring with the FS mounted just five feet off the ground (so I could see what was happening) the link seemed to get stuck between the two 'coils' of the girth hitch. When there is only one 'coil' (as with an eye splice) the link can slide to either side of the one coil of rope and pass through the ring. With the two coils of the girth hitch one side of each coil will cause the link to jam, because the link ends up between the two coils. Using a link that is small enough to pass between the rope and the big ring seems to have solved that problem, but I need to use it more to feel confident that it won't get stuck.

It seems that the way the system is loaded turns the big ring so that the coil(s) of the girth hitch are often in line with the screw link when the climbing rope is pulled through the big ring. I have also thought of eliminating the screw link for this application. The FS releases quite readily once the rope passes through the big ring and the eye splice in the climbing line is thick enough to prevent the rope from going through the small ring unless you give it a good, solid tug.

When I oredered the large rings from Sherrill I was told that they have to be special ordered because Sherrill needs to order a certain quantity. If you decide to order some big rings let me know. I'll probably get a couple more also. Perhaps other people here would also be interested.

Mahk