Toggled Suspension System

[TeeDee]

Frawg - your results are the same as mine using the constrictor arrangement that ZA206 originated. I went from an 8" bury which slipped to a 24" bury which didn't slip. I noticed as you have, that with the 24" bury only a fraction of the bury near the end at which the force is applied was effective. The opposite end was usually loose and ineffective.

I then abandoned this method and adopted carboy's method which applies force to both ends of the constrictor. This makes the full length of the constrictor fully effective and a much shorter length can be used and no back-up half-hitches or any other knot is needed.

That is also why eye splices with a fully buried tail are so effective and are rated at between 97% and 100% of the rated rope strength. With the eye splice and buried tail, the force is applied to both ends of the bury.

Okay, I had my coffee and made another UCR. It actually held without slipping, even with me bouncing a bit in the hammock.

What differed this time was that I made the bury 18" long, a bit under 8 fids for the 7/64 AmSteel I'm using.


So, an 8" bury failed and an 18" bury succeeded. I'll experiment with bury length to find the tipping point.

The idea I alluded to in my previous post was to put the slippery half hitch at the tailing end of the bury, rather than as a stopper at the head end. Though it seems counter-intuitive, I think it ensures that both ends of the bury are initially under tension which, in turn, induces the compression whereby the bury grips the inner line.


It may also be that part of this morning's success with the 18" bury was to 'milk' the length of the bury prior to loading the line, making sure that the bury and the enclosed line made good contact so the constrictor could bite.

There is obviously some threshold length for the bury. I believe that a short bury could still be made to hold by using a hitch at its tail -- slippery half hitch, rolling hitch, sailor's gripping hitch, etc, etc. I'm not sure what the active mechanism is. Perhaps the tailing hitch merely needs to compensate for the friction deficit of the short bury. I lean, though, toward my initial idea -- that the hitch ensures initial tension at both ends of the bury.

Hope that makes sense, but I am open to correction and education.

Chuck

[Frawg]

...I then abandoned this method and adopted carboy's method ...

I should mention that caboyer has gone into witness protection, and left this guy 'Frawg' to talk for him. (Thank you, Angry Sparrow!)

Anyway, I've come back to the UCR now that I figured out how to make it work. Both methods seem good to me, but I'm going with the one that uses less line for given maximum span. That line is so heavy, ya know!

Chuck

[TeeDee]

I should mention that caboyer has gone into witness protection, and left this guy 'Frawg' to talk for him. (Thank you, Angry Sparrow!)

Anyway, I've come back to the UCR now that I figured out how to make it work. Both methods seem good to me, but I'm going with the one that uses less line for given maximum span. That line is so heavy, ya know!

Chuck

Yes - the method that ZA206 originated uses less line, but even after I figured out how to use it, I still just don't trust it. Not after I saw how much of the constrictor was ineffective because of the asymmetrical force applied. I've had too many methods slip to trust one after it slipped on me. And if I need special back-up knots or special procedures to execute, I don't use them anymore. One of the reasons I was glad to leave webbing behind was because the ring buckles needed that extra half-hitch just to be sure - well that and all the extra weight and bulk of the webbing . I'll like the peace of mind and safety of the Whoopie Sling method.

Also, I set-up both the UCR method and the Whoopie sling method and compared the amount of rope for each for my suspension. I design a suspension for a 20' tree span and a 10' ridge line length. The ridge line rope is identical for either method, so I only needed to compare the end pieces, from the ridge line attachment point to the tree hugger.

I came up with the following rope lengths needed for the two methods:

1. Whoopie Sling method - 12' each end, 24' total.
2. UCR method - 10' each end, 20' total.

So for my set-up, I got a 4' total difference in the two methods. With my AS-78 rope, that comes to 0.3 oz weight difference. If I use my 3 mm amsteel, the weight difference is only 0.2 oz.

I think that for me the UCR method may even use a bit more than I list above since I only used a 12" constrictor in making the UCR end. For me to trust the UCR method on a daily basis, I would want to extend that to a minimum of 15".

So, for me, I found the difference in needed rope lengths to be very minimal.

But that's one of the things that makes all of this so much fun - so many different ways of accomplishing the same thing.

[Frawg]

Good stuff, TeeDee! With the collective thinking of this group we have iteratively converged to a pretty sweet suspension setup, with subtle differences that should be expected when optimality criteria differ slightly.

Just to ramble a bit, if I may, about how my thinking evolved -- I originally got started with toggles based on the double descender ring suspension. I'd visualized a toggle as a short segment of an infinite radius ring, and gravitated to it because of its potential for quick (dis)connect. Even tried using a toggle with a carabiner in place of the second descender ring; while that worked,the strapping was still heavier and more prone to slipping or misalignment than I liked. I then tried the Garda hitch with the AmSteel line but that still left me with alignment and slippage concerns, and Grizz's misgivings about the line getting squeezed gave me some pause. Concomitantly, HC4U's SLS approach looked pretty good to me, but I really wanted a removable ridge line. Then your marlinspike approach caught my eye and something about it intuitively felt rignt. The only other thing I wanted was to be able to swap out 'modules' quickly and easily, as well as free up the ridge line. Finally came the discussion following ZA206's UCR post and harmonic convergence ensued.

As a further aside, one of the projects I'd been involved with in my waning days in uniform was a so-called "Modular Building Block" program for communications systems. It was a pretty cool approach - almost like a set of Legos for deployable comms. Mac's 'Molly Mac Pack' is another one of those things that feels 'right' to me, and I look forward to seeing how that goes. That mindset has been ingrained in me for a few decades now. I think I even still have the Byte magazine issue on Smalltalk somewhere in my files.

Anyway, all told I'm pretty happy with how this has evolved. If this were math I'd call it an 'elegant solution'. This has been a fun thing to think about and play with.

Cheers!

[TeeDee]

Good stuff, TeeDee! With the collective thinking of this group we have iteratively converged to a pretty sweet suspension setup, with subtle differences that should be expected when optimality criteria differ slightly.

Just to ramble a bit, if I may, about how my thinking evolved -- I originally got started with toggles based on the double descender ring suspension. I'd visualized a toggle as a short segment of an infinite radius ring, and gravitated to it because of its potential for quick (dis)connect. Even tried using a toggle with a carabiner in place of the second descender ring; while that worked,the strapping was still heavier and more prone to slipping or misalignment than I liked. I then tried the Garda hitch with the AmSteel line but that still left me with alignment and slippage concerns, and Grizz's misgivings about the line getting squeezed gave me some pause. Concomitantly, HC4U's SLS approach looked pretty good to me, but I really wanted a removable ridge line. Then your marlinspike approach caught my eye and something about it intuitively felt rignt. The only other thing I wanted was to be able to swap out 'modules' quickly and easily, as well as free up the ridge line. Finally came the discussion following ZA206's UCR post and harmonic convergence ensued.

As a further aside, one of the projects I'd been involved with in my waning days in uniform was a so-called "Modular Building Block" program for communications systems. It was a pretty cool approach - almost like a set of Legos for deployable comms. Mac's 'Molly Mac Pack' is another one of those things that feels 'right' to me, and I look forward to seeing how that goes. That mindset has been ingrained in me for a few decades now. I think I even still have the Byte magazine issue on Smalltalk somewhere in my files.

Anyway, all told I'm pretty happy with how this has evolved. If this were math I'd call it an 'elegant solution'. This has been a fun thing to think about and play with.

Cheers!

I can appreciate the history and evolution. I started with the figure 8 wrap, soon got tired of doing and redoing the wrap. Moved to webbing and cam lock buckles for their easy use. Left them for the ring buckles because of weight. Left the ring buckles and webbing because of the weight and bulk for rope and the Carabiner Hitch. Left that for the SLS for less adjustment, think no adjustment, and sightly less weight.

Have now moved on to the MSLS for modularity and easier set-up and slightly more weight, less than 1 oz more.

Having used and programed Unix style systems for almost 30 years, I like and appreciate a modular system. Easy to fix and adapt for various needs.

I like the use of splices and the bury splice since I don't have to de-rate the rope as I do with knots. With a knot, I'll lose maybe 25% to 40% of rated strength if I'm lucky, more if I'm not. With the bury splice, I'll lose a maximum of 3% and probably considerably less than that.

A splice I do once and then just use it. A knot I have to tie and untie every time. I'll still use knots when one is better than a splice.

[Frawg]

Very cool, TeeDee. Hope we get to meet up sometime!

[nacra533]

I hope everyone else was following this thread and enjoyed it as much as I did. I think the collaboration on something that started as a "Neat, but you'll kill the forest with ropes" post (ZA206's original UCR thread) turned into some great colloborative innovation. There were at least 3 people doing 3 similar but different things and each "borrowing" ideas from each other to come up with multiple systems that can be tweaked for individual preference.

[TeeDee]

I hope everyone else was following this thread and enjoyed it as much as I did. I think the collaboration on something that started as a "Neat, but you'll kill the forest with ropes" post (ZA206's original UCR thread) turned into some great colloborative innovation. There were at least 3 people doing 3 similar but different things and each "borrowing" ideas from each other to come up with multiple systems that can be tweaked for individual preference.

Yes. Definitively.

One of the great things about HF is the collaborative efforts and the sparking of ideas from one another.

That is probably why HF becomes so addictive.

Just the thought of chemicals leaves me cold, but ideas, ahhhhhhhhh !!!!!! Those are my addiction.

[TeeDee]

I can appreciate the history and evolution. I started with the figure 8 wrap, soon got tired of doing and redoing the wrap. Moved to webbing and cam lock buckles for their easy use. Left them for the ring buckles because of weight. Left the ring buckles and webbing because of the weight and bulk for rope and the Carabiner Hitch. Left that for the SLS for less adjustment, think no adjustment, and sightly less weight.

Have now moved on to the MSLS for modularity and easier set-up and slightly more weight, less than 1 oz more.

Having used and programed Unix style systems for almost 30 years, I like and appreciate a modular system. Easy to fix and adapt for various needs.

I like the use of splices and the bury splice since I don't have to de-rate the rope as I do with knots. With a knot, I'll lose maybe 25% to 40% of rated strength if I'm lucky, more if I'm not. With the bury splice, I'll lose a maximum of 3% and probably considerably less than that.

A splice I do once and then just use it. A knot I have to tie and untie every time. I'll still use knots when one is better than a splice.

I forgot one suspension I used - the zig zag cleat.

That was about the time I developed the carabiner hitch.

Then I finally developed my version of the SLS and left the hardware behind. Finally a suspension system that was easy to use and didn't use any hardware

Is the MSLS the end of my suspension development/evolution?

I thought the Carabiner Hitch suspension was the end and then I was sure my SLS was the end and now I know that the MSLS is the end.

[SlowBro]

Tonight I posted a detailed tutorial "Whoopie Sling Mod to WBBB" on making a whoopie sling out of the AmSteel suspension line on my hammock. This will work for any woven hollow core high tech line.

I think this is similar to the system that TeeDee is using and the one Frawg was using before he moved to the UCR setup. I actually built both systems and used one on each end of my hammock. I ended up going with the Whoopie sling version because I could make it a little shorter (the trees in my back yard are very close together) and I had one episode of slippage with the URC when I forgot to tighten it up properly. Both systems are pretty sweet.

If you have or can put a spectra woven hollow core line on your hammock (AmSteel blue, AS-78, etc) then you can try out a whoopie sling with about 5 minutes of work. no knots. no fancy tools. And if you don't like, it pull it apart and your back where you started. If you couple it with a marlin spike toggle system on your tree slings you have the quick setup and adjustability of the ring buckle system without the weight or wear that system includes.

-SlowBro