swl

KevinS

KevinS

Branched out member
Location
ontario
I am playing around with some 1/2" 3 strand nylon with a tensile strength of 4536 lbs.
Let's say being safe a 10:1 would be 453.6 lbs or 5:1 would be 907.2 lbs I think.
What would that system in a basket be swl? It will be a properly spliced ring to ring rigging friction saver for a false crotch, therefor always in a basket.

As well I am making some spider legs, again light duty only, with 1 over sized spliced eyes. Also 3 strand nylon.
3/8" tensile strength - 2592 lbs (10:1= 259.2 lbs, 5:1= 518.4)
1/4" tensile strength - 1190 lbs (10:1= 119 lbs, 5:1= 238 lbs)

Wondering if I have figured this correct or if there is any obvious things I am over looking. As I said these aren't for negative blocking oak into just those long skinny limbs over the deck, etc light duty.

Hope this isn't to dumb of a question, thanks.
 
From what i am believing right now:

since a basket configuration results in two legs of line it should be 2x swl assuming of course there is the proper bend radius for the rope with the minimum being bend radius diameter = rope thickness x 4. using something for life support i would go with a 10:1 configuration for added redundancy.

I wouldnt use that half inch 3strand as it doesnt meet the reqquired specifications of 5000lbs tensile necessary to be approved for life support. Yes, it would function in that way, but it wouldnt meet specifications

and im sure other people will chime in as well.

If you found 3strand over 5k lbs tensile it does make a good frictionsaver device, as seen here

http://www.sherrilltree.com/Professional...h.FcwI6Rre.dpbs
-Steven
 
then i fully agree it will be great to use,

but for simplicity, i would personally use a nylon loop runner & carabiner/ rigging ring in place of the FS all because it saves the need to splice in rings, and also you can change hardware between just a rigigng ring, or a biner/pulley combo whenever you want much easier. and it can be choked off when necessary. but thats just my 2cents

-Steve
 
Kevin, if we are talking rigging slings for other uses (crane use, tie downs...) most use a 5:1. The rating starts with the vertical pull test, then goes to the 5:1, then is adjusted % for choker and basket. That is because you are not using knots and the uses change too, meaning no friction from a tree and such. Make sense?
 
Mark that makes sense what are the percentages of loss for chocker, basket, etc.

Steve I do use nylon runners a lot with the ring cow hitched and a biner. But some times when its grabbed and ring taken off I've lost a couple rings with groundies setting them who knows where. So if I make a dedicated system they can't take apart it should fix that. As well it frees up my slings and biners as separate rigging chokers, redirects etc.

I love the fact that it's retrievable remotely so I don't have to reclimb/ climb everything like a chocker, but Iknow it's always still an option
 
There are a lot better choices as far as false crotches for rigging go. All of the pictured systems have MBS of 9k or greater. Blue 9,500lb - yellow 14,000lb - orange 23,000lb

1240015_10202304669924235_1679404764_n.jpg


3.JPG


IMG_5935.JPG


IMG_5804.JPG


Or if you want even more versatility from a rigging system, the rigSAVER

IMG_5775.JPG
 
Another question about spider legs should they be strong enough to take the load of the piece or does it just need to hold 1/2 the load?
I know it depends on angles etc but going with the minimum it should only see half the load?
 
bonner the x rings for heavy rigging are a beautiful thing and for sure are on my list. I will have a 3/4" tenex 3 ring sling, beefier version of x man's favourite.
However for small condo pruning or I've been using them as high tie ins for pine pruning etc. they seem excessive seeing every piece can be lifted and carried by one person. But your slings do look great.
 
The 1/2" double braid slings might be a light rigging option. My first rigSAVER was made out of 3 strand line (5k lb mbs) I dropped some relatively large loads on that with no issue.

Maybe just get a normal steel ring and a forged rigging ring, do that up on a 3 strand sling, then put a Pinto rig on it. It will work as a R/r friction saver and have all the function of a uSAVER or PulleySaver.

One of the best things about the forged steel ring is that it easily passes an overhand knot in a rigging line. Im not big on retrieval balls or quicklinks, I mean they work but its a pain. I try to make anything remote able to be set with just a throwline and the throwball and retrievable with a knot. Depending on materials its not always possible of course.

For rigging its especially useful to just use a knot because climbing or in the bucket you might switch the rigging point up a few times and not needing a bunch of extra stuff is handy.

I dont sell any of the slings I make, so take it for what it is. If you wanted one though I would make one up for you if you spring for materials and shipping.
 
Reading up on spider legs it says put the rigging line on the heavier butt end. But when you're doing smaller limbs when you're doing long small limbs tip heavy because of foliage/ crown do the lines switch or just always rigging line to the butt.
 
I think they might say to put the rigging line on the butt end because there is a chance of the tip tied portion to break. with the main line on the butt there are less variables to create a failure in the system, knots carabiners, whatever you use to connect the second or third leg. Although I have never read this personally.
 
Mark spider legs aren't usually in negative blocking it's for rigging with a high tie in at most swinging and lowering what kind of shock loads do you mean?
 
You must log in or register to reply here.

New threads New posts

Back
Top Bottom