whew!Originally Posted by warbonnetguy
yeah, i heard that too, but i called and ordered a whole bunch the other day and the person i talked to said they hadn't heard that. package arrived and it's the same stuff. hopefully it is just a rumor, probably started by those strapworks webbing fans
I'm going in for another box ASAP.
thanks
Grizz
I posted some information a while ago that I got from OWF. They sent me an email saying that the camo webbing they were selling at the time was no longer manufactured, but that they would start selling a similar camo webbing with a higher load rating once they ran out of their stock. I am not sure how much their information can be trusted, though, since they seem to be giving vastly different load ratings for their webbing to different people. The webbing, however, is great and seems plenty strong.
You guys are saying the pull factor is 3:1. Wouldn't it be just 2:1? If I pull 2 inches, the rope in front of the hook moves by 1 inch, isn't it?
The 3:1 is the mechanical advantage, meaning that it's easy to tighten the rope with minimal muscle exertion. Sorta like a pulley or block and tackle system. As soon as Grizz reads this, formulas will be forthcoming
Last edited by headchange4u; 09-02-2008 at 21:26. Reason: i ca'nt spel gud
“Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it." -Terry Pratchett
you rang?The 3:1 is the mechanical advantage, meaning that it's easy to tighten the rope with minimal muscle exertion. Sorta like a pulley or block and tackle system. As soon as Grizz reads this, formulas will be forthcoming
I think of it in the following way. You have a couple of endpoints your loops are going through. At any given time your working end is coming out of one of those loops. Count the number of times the cord passes through that particular loop, say N times. Now pulling the working end one foot means that the N cords through the loop absorb that one foot, divided evenly among them. So in this case you have an N:1 mechanical advantage.
So the cord going once through a pulley? 1:1. Take that cord back to the anchor loop and through, now you have the cord appearing twice there (the first time where it originates, the second time when the cord came back through.) 2:1. Taking it back up to the other pulley and through doesn't really give you any more mechanical advantage because of the one-to-one movement between the working end and the cord just on the other side of the pulley from it. But take it back down to the anchor loop and you're up to 3:1.
So it seems to me anyway. You need a full circuit between loop endpoints to increase the advantage by another unit.
Grizz
I think you can just count the number of lines on one side of your reference point (the knot and the loop you make for the trucker's hitch) and the number of lines on the other side. You get 1:3, the 1st loop around tree on one side and then the two you get going through the trucker's hitch you make. The loop around the tree functions like a fixed pulley and the loop for the trucker's hitch functions like a movable pulley... so it is like a two pulley system in theory.
So you have to pull 3 inches to get the hook to move by 1 inch.
Youngblood AT2000
"Cinch Buckle System:
Cinch buckle w/ ~18" of 7/64 Spectra = 1.2 oz x 2 sides = 2.4 oz
10' OWF camo webbing = 2.3 oz x 2 sides = 4.6 oz
Camp Nano biner = 1.1 oz x 2 sides = 2.2 oz
Total weight = 9.2 oz
Ring Buckle System
2 descending rings w/ ~18" 7/64 Spectra = 1.1 oz x 2 sides = 2.2 oz
10' OWF camo webbing = 2.3 oz x 2 sides = 4.6 oz
Camp Nano biner = 1.1 oz x 2 sides = 2.2 oz
Total weight = 9.0 oz
Truckers Hitch System:
20' 1/8 Amsteel Blue w/ 1 descending ring = 2.1 oz x 2 sides = 4.2 oz
5' tree hugger = 1.4 oz x 2 sides = 2.8 oz
Total = 7 oz"
With all due respect, i'm curious per the weight you say the descending ring weighs, looks like steel to me, and i can't believe it weighs less than 2+ ounces ea.
Well here goes...
-5' of 'muletape'(1/2 inch),(for tree straps)x 2 sides=1.5oz.
-aluminum rap ring(omegapac)=1.3oz
=3 oz + weight of your blue rope
By your math, 20' 1/8 Amsteel Blue w/ 1 descending ring = 2.1 oz x 2 sides = 4.2oz. I say that aluminum rap rings are usually half the weight of steel rings, that being said, i say that by using aluminum you should shave your weight by at least 1.5 ounces. which would bring the total to 4.2 ounces, but i'm loco
Last edited by locorogue; 03-16-2009 at 01:01. Reason: correction
wow, it's been a while since this thread got poked.
I don't think I did the numbers you cite, but I checked out the 1.1 oz given for 18" of lightweight cord and two rings.
The rings in question are almost surely aluminum SMC descending rings. These are strong and weigh 0.4 oz each. I have several, and the weight checks out. My memory of cord weight for this class of cord is 0.2 oz/ ft, which brings the weight of 18" of cord and two rings at 1.5*0.2 + 2*0.4 = 1.1 oz. Spot on.
Grizz
Yes I am referring to the SMC aluminum rings. Really light and strong.
“Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it." -Terry Pratchett
I've never seen those rap rings(per your truckers hitch setup), until now! I'll prob grab some, at least for a setup as you described. I climb(rock, indoor, etc) quite often, and i'm just one of 'those guys' who has to have the highest 'kn' in all my gear, so it was an overlook on my part. I do like your setup. And the 'muletape' i suggested, only shaves maybe 3/4oz off the total.
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