- Location
- Charlotte, NC
spyder nice work. keep the good art work comeing please
be safe scotty
be safe scotty
Retreivable false crotch for rigging
- Thread starter rfwoodvt
- Start date
- Location
- Retired in Minneapolis
Here is a project that I thought up and Nick executed.
This is a heavy duty variation on the adjustable false crotch that many folks use for climbing. The function is the same but the components are much more robust.
Right now I haven't worked through the 'numbers' on each of the components to come up with an idea of what size loads the system could stand. Suffice it to say, it would work for a lot of rigging.
The yellow ring is 9/16" diameter and is used for crane rigging. Nick made up the orange sling out of Yalex and the adjustable eye sling is...dang...memory cramp...someone will tell me
The block is a heavy duty stainless steel cheek plate unit.
The biggest concern that I have is what load it would take to have the Kelmheist to slip. To put that concern to rest I tied a stopper knot just below.
The rigging rope would be retrieved in the same way that the climbing AFC would come down but a bigger rope or cord would have to be used. I'm afraid that a throwline could jump the between the cheek plates and lower sheave which could jam things.
The main application that I see would be in a tree where a high rigging point is chosen to work a lower limb. Being able to retrieve the FC from the ground instead of having to send the climber back up to the rigging point would save energy.
Give me some feedback...any limitations or concerns that I'm missing?
This is a heavy duty variation on the adjustable false crotch that many folks use for climbing. The function is the same but the components are much more robust.
Right now I haven't worked through the 'numbers' on each of the components to come up with an idea of what size loads the system could stand. Suffice it to say, it would work for a lot of rigging.
The yellow ring is 9/16" diameter and is used for crane rigging. Nick made up the orange sling out of Yalex and the adjustable eye sling is...dang...memory cramp...someone will tell me
The block is a heavy duty stainless steel cheek plate unit.The biggest concern that I have is what load it would take to have the Kelmheist to slip. To put that concern to rest I tied a stopper knot just below.
The rigging rope would be retrieved in the same way that the climbing AFC would come down but a bigger rope or cord would have to be used. I'm afraid that a throwline could jump the between the cheek plates and lower sheave which could jam things.
The main application that I see would be in a tree where a high rigging point is chosen to work a lower limb. Being able to retrieve the FC from the ground instead of having to send the climber back up to the rigging point would save energy.
Give me some feedback...any limitations or concerns that I'm missing?
Attachments
rfwoodvt
New member
- Location
- This side of eternity.
Tom!
Once again, you've made me have to take myself out the the wood shed for a lashing!
I've been using something similar to what you showed in the pic for a number of years now. Albeit I've been using it for my climbing lines when working down a spar.
Never occurred to me to up-size it and install it from the ground over a limb.
Just another Homer moment, I guess...DOH!
Time to play around with this one!
Once again, you've made me have to take myself out the the wood shed for a lashing!
I've been using something similar to what you showed in the pic for a number of years now. Albeit I've been using it for my climbing lines when working down a spar.
Never occurred to me to up-size it and install it from the ground over a limb.
Just another Homer moment, I guess...DOH!
Time to play around with this one!
- Location
- Retired in Minneapolis
Rick,
I had a similar moment when I was rooting through my bucket of rigging gear. The yellow ring burbled to the top of one bucket and a heavy loopie in another...hmmm...combine the two...been doing a light weight version, like you :0
The AFC that I use for climbing has an adjuster that's a bit shorter than this one in the picture.
I had a similar moment when I was rooting through my bucket of rigging gear. The yellow ring burbled to the top of one bucket and a heavy loopie in another...hmmm...combine the two...been doing a light weight version, like you :0
The AFC that I use for climbing has an adjuster that's a bit shorter than this one in the picture.
- Location
- Boulder County, CO.
Takes a lot of burbling to get to the top of your bucket, Tom
Thanks for the animation, Spider.
Thanks for the animation, Spider.
- Location
- Bloomington, Indiana
How much friction would there be on the rigging ring? Using this type of setup for climbing, the rig tends to see-saw back and forth depending on which way the rope is running. Seems that you would want the rope to have the load when it is running over the block first and then the ring, as in your photo. I think there would be less friction running the rope in this direction (block, then ring, when loaded), but I still wonder how much friction. Wouldn't want to burn the double braid.
- Location
- Retired in Minneapolis
Mahk,
So...you're suggesting switching ends of the rigging line? Seems like a good idea
So...you're suggesting switching ends of the rigging line? Seems like a good idea
- Location
- Bloomington, Indiana
[ QUOTE ]
Mahk,
So...you're suggesting switching ends of the rigging line? Seems like a good idea
[/ QUOTE ]
Not sure what you mean by 'switching ends'...
But, what I meant was that when the load is on the line (i.e. when the rope is running with the piece) the rope should be running through the block first, then the ring. I think that this would create less friction than running the rope the other way (ring first, then block when loaded), but I think that there would still be some friction between the (running) rope and the ring. How much friction I don't know.
Mahk,
So...you're suggesting switching ends of the rigging line? Seems like a good idea
[/ QUOTE ]
Not sure what you mean by 'switching ends'...
But, what I meant was that when the load is on the line (i.e. when the rope is running with the piece) the rope should be running through the block first, then the ring. I think that this would create less friction than running the rope the other way (ring first, then block when loaded), but I think that there would still be some friction between the (running) rope and the ring. How much friction I don't know.
NickfromWI
Participating member
- Location
- Los Angeles, CA
I think by switching ends, he means pulling the rope up so the ground end is the side you're now tying to the pieces you're lowering, and the groundy is using the old "wood" end to run through the GRCS.
The slings were made of 5/16 Ultra-tech. A proper core-to-core splice is on that, hence the long length. I could have made it signifigantly shorter by going with locking brummells, but it would come at a cost of strength, so I went for the real deal.
Here's a detail of the chafe guard...
love
nick
The slings were made of 5/16 Ultra-tech. A proper core-to-core splice is on that, hence the long length. I could have made it signifigantly shorter by going with locking brummells, but it would come at a cost of strength, so I went for the real deal.
Here's a detail of the chafe guard...
love
nick
Attachments
NickfromWI
Participating member
- Location
- Los Angeles, CA
Thanks! Yes, still in LA. Glad you like the splice! I'd be glad to come down and splice a bunch of stuff one day. PM me.
I wonder if there could be some sort of a fattener put on the yellow ring to increase the diameter and be more rope friendly?
love
nick
I wonder if there could be some sort of a fattener put on the yellow ring to increase the diameter and be more rope friendly?
love
nick
R
rich_h
Guest
Nick,
Sweet splicing and an excellent idea all around.
I know if may be overkill but what about using a 7/8" pear shaped ring? It wouldn't be all that much heavier, similar in size, and would be a little friendlier on the rope. I have used the 7/8" pear for multi-legged slings for cranes and they work great.
Sweet splicing and an excellent idea all around.
I know if may be overkill but what about using a 7/8" pear shaped ring? It wouldn't be all that much heavier, similar in size, and would be a little friendlier on the rope. I have used the 7/8" pear for multi-legged slings for cranes and they work great.
- Location
- Retired in Minneapolis
After Mahk's comment I got to thinking about adding a sheave on the ring end.
Using a large diameter shackle with a sheave on the pin end would work. The challenge is to size things correctly. If I go this route I'll have to cut off the yellow ring. Not too big a deal...
Using a large diameter shackle with a sheave on the pin end would work. The challenge is to size things correctly. If I go this route I'll have to cut off the yellow ring. Not too big a deal...
- Location
- Home of the New Jersey Devils
Tom, I wonder if the sheave would lie against the pulley alright? Why not create a heavy duty "rigging" rope guide?
- Location
- Retired in Minneapolis
Mark,
That's what I thought of last night as this idea is jelling.
That's what I thought of last night as this idea is jelling.
NickfromWI
Participating member
- Location
- Los Angeles, CA
[ QUOTE ]
Why not create a heavy duty "rigging" rope guide?
[/ QUOTE ]
So all we'd need is a ring big enough to fit the pulley, and some sort of a retriever on the end, and that should be the easy part.
I think I know a place to get the ring...I try to bring some pics later.
love
nick
Why not create a heavy duty "rigging" rope guide?
[/ QUOTE ]
So all we'd need is a ring big enough to fit the pulley, and some sort of a retriever on the end, and that should be the easy part.
I think I know a place to get the ring...I try to bring some pics later.
love
nick
