Kong Double Ascender

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Double line isn't easier just less hassle of haveing to ask someone to untie a rope. I always feel like I am imposing work on someone else who is trying to get something done themselves. Going double is Ok for short hikes. It does get heavy right about 50 feet. The rope in single line doesnt get that heavy until 100 feet and your gonna be little winded anyway at 100.
 
TM- the 11mm are way LESS than 11/13ths. Remember, area (which in this case affects mass) = pi R squared.

The area of a cross section on 13mm rope is 126.61mm. A of an 11mm rope is 95.03. This equates to about a 25% difference, way more than the measily 11/13ths!

11mm way lighter.

love
nick
 
You are so right! Another plus for 11 mm technology. Genius boy, you've done it again!

Yes, the simple, off the cuff 11 divided by 13 would show 84.6%, or around 15% reduction, when more realistically 95.03 divided by 126.61 = 75.2%.
The 95.03 comes from the 11 mm. You take the radius, which is half the diameter, or 5.5 mm. Square that radius, 5.5 times 5.5 =30.25, and then multiply that by pi, or 3.14, and you get 94.98..... wait, Nick got 95.03.... oh, GEEK BOY has to use pi out to 4 decimal places. OK, 30.25 times 3.1415 = 95.03 square mm cross section GEEK!

Whipping through the math, the 13 mm has a square area cross section of (6.5 x 6.5 x 3.1415) = 132.7. Genius boy, you got 126.61.... this is significant, where did I screw up?

95.03 divided by 132.7 = 71.9 % , a 28% reduction in square cross surface area. This does not equate to weight, just cross section.
 
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Jim, you can make it a bit easier on yourself.&nbsp; Since pi is a common factor you can leave it out.<blockquote>(11&divide;2)&sup2;&divide;(13&divide;2)&sup2;=0.7160</blockquote>That'll get you the relative <i>volume</i> for a given length of rope.&nbsp; The <i>mass</i> may be another set of figures altogether...

:<tt></tt>)
 
As glens has pointed out, you can quickly determine the VOLUME once you have the surface area of the cross section. The volume would be for a hollow tube of rope 11mm wide and 150' long. Weight/mass comes from this. You can fill that tube with water and measure it....or better yet, fill it with polyester fibers. This is what we are doing when we weigh a rope. Filling the tube with polyester.

From this, you can see that an 11mm rope is MORE than 11/13ths lighter than a 13mm.

love
nick
 
Nick,

There are more variables than simply displacement.&nbsp; A quick flip through the Sherrill catalog indicates weight of any given general rope construction covers a range of values for the same nominal size.

In order to use the relative volumes to project a relationship between the weights, one would have to assume material/density as being constant such as pi was in my previous post.

Glen
 
Here is a chart from my most dog eared knot referance book; giving good, general layout of a charachteristics of materials and braids. General weight of materials etc. Much of our stuff is polyester and nylon. Nylon giving about the same strength, with more of that elasticity stuff in it. Also, by braid type; 3strand is more elastic.

Use the hidden, floating in Lower R.Hand corner, click button to enlarge to readable.

:alien:
 
mathturbation

(11÷2)²÷(13÷2)²=0.7160
That'll get you the relative volume for a given length of rope.
Volume is in cubic units, not square units.

Volume = pi r-squared h, where h (height) = the length of the rope. 150 feet = 4,572 cm, or, since we're working in mm, 45,720 mm

the volume of a 13 mm rope is then 6,068,341 cubic mm in volume and an 11 mm rope is a mere 4,344,789 cubic mm in volume.

The math works because if you divide 4,344,789 by 6,068,341, you get the same 0.7160, which means the 11 mm has 71.6 % of the volume a 13 mm.

This is a stupid exercise. I doubt anyone cares that I know how to use a calculator.

To calculate the weight, we would need to know the density, which is in grams per cubic (at least in our case here) mm. Also irrelevant because the manufacturers provide us with the weight per 100 feet and we can direct compare, with no math.

What was this thread about?
 
Re: mathturbation

Originally posted by Tree Machine
(11&divide;2)&sup2;&divide;(13&divide;2)&sup2;=0.7160
That'll get you the relative volume for a given length of rope.
Volume is in cubic units, not square units.
...
What was this thread about?
Regarding that last question, I forget now.

You did well to include the whole sentence after the equation.&nbsp; I'm somewhat puzzled.&nbsp; It seems as though you're correcting me yet I clearly implied by that phraseology that the <i>relative volume</i> would be based upon the <i>relative area</i> when the third dimension became available (the <i>given length of rope</i>).&nbsp; Both of the common factors, pi and length, can be omitted from the equation used to determine the <i>relative</i> areas/volumes, but those factors are indeed necessary to obtain discrete values.&nbsp; As you ably indicated.

I apologize if I mis-read you there and that I felt the need to defend myself as a result.

Glen
 
Thanks guys. This is too much fun. Glen you're right. I know (trust me on this one) that all ropes are not the same. I WAS assuming a constant type of construction. I just want people to walk away from this knowing that just because a rope is 10% bigger in diameter, doesn't mean it will only be 10% heavier. It will be more than that (assuming 2 similar/same rope constructions).


love
nick
 
re-gathering our thoughts

Yous guyz are a buncha jeaniuses. The topic was Kong dual ascenders. It moved to backing them up when out of nowhere Chucky dropped the bomb, got us all stirred up, won the Nobel prize and hitch dude of the year though thoroughly crediting Nick from Wisconsin for the inspiration. TreeCo came on with the Symmetrical Nelson, and Nick from Wisconsin was right there with an inverted version. Spidey said the dual Frenchy works and added the regular ol prussik works also. Glen described a hitch, yet unshown, and Roachy stated that two tress cords, each one fashioned into a VT on each line will work, a version of which I started with on page 1 or 2.

Did I miss anyone?

Oh, yea, ZenMaster Bayou Boy and his futuristic means hit us with...
http://www.arboristsite.com/attach/18222.jpg
 
I thought mebbe we should send a letter to Kong and pitch a modification to their Duals that would allow the easy insertion of any biner to hold the ropes captive in the shell and serve as an attachment for the backup hitch.

I've put together a draft, for all your inspection. If and when we agree on the content, let's fire it across and seee if we can engage some necessary change. See, the Kongs are not built as a dual ascender. They're simply two Kong single ascenders with a handle, all riveted together. The top holes in the ascender are there for backing up in a single ascender configuration. when the two get riveted together as one, the existing holes no longer function, though I doubt this has ever been brought to their attention...... until soon.
 
Looks good. I don't know what else to tell them.

Chucky, I will not and cannot accept credit for the idea. We were simultaneously working off eachother. I'll take 50%, but no more. Good idea, chuck.

Incite change.

love
nick
 
Nice start on letter; i think to make case stronger etc.; ya might include how more and more arborists are being commanded not to spike, seeking such means as their products to ascend etc.

ZenMaster Bayou Boy and his futuristic means should know that the sound of 1 hand typing is not the same as the sound of 1 hand clapping:blob2:
 
Fabulous team work!

Thanks Daniel, and others. Changes noted, amendments will be made. Attached is a letter I sent to Kong last July, but have been negligent in following up. We, together, are creating the followup.

quote:Chucky, I will not and cannot accept credit for the idea. We were simultaneously working off each other. I'll take 50%, but no more. Good idea, chuck.

So we call it the NickChuck? The Chucky from Wisconsin?

Nick, some time ago you were working on, what legend has it, the 'lost hitch'. You were intent on inventing a hitch. This was some time ago. Can you enlighten us? I have a feeling this was the track you were on. Yes, no?
 
da letter

Successful arborist and tree climbers working together from around the world have have been investigating new techniques for climbing tree work. Your ascender is being focused on and inorder to fully utilize it's expanded potential we, jointly are requesting ...

Something like that, so that it includes others by authority.

Jack
 

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