Rigging a hammock with constrictor ropes (UCR's)...

**amac** · 07-09-2009, 18:23

TiredFeet. Thanks for the explanations of why the Whoopie may be preferred over the UCR. One thing's for sure, here, it will be interesting to hear from the forum's members how these two new systems perform over time.

**amac** · 07-09-2009, 18:37

Originally Posted by TiredFeet

...By the time you add up the 2 eye splices and the longer adjustable bury for each end, the shortest length of the UCR is just too long to be practical for us.

I was puzzled for a while by your statement, and finally realized why. I'm not using 2 eye splices, for the exact reason you mentioned...they take up too much room. I tied simple knots. I can slide my constrictor from end to end of the line attached to the tree (is it called the bury-line? or maybe the static line?) I will post pics soon.

**Frawg** · 07-09-2009, 18:42

Originally Posted by amac

I was puzzled for a while by your statement, and finally realized why. I'm not using 2 eye splices, for the exact reason you mentioned...they take up too much room. I tied simple knots. I can slide my constrictor from end to end of the line attached to the tree (is it called the bury-line? or maybe the static line?) I will post pics soon.

FWIW, I also have just one eye splice. The other end holds a toggle secured by a slipped eye, which takes up maybe 1.5". I suppose that could be a 'last straw".

**TeeDee** · 07-09-2009, 19:10

Originally Posted by Frawg

FWIW, I also have just one eye splice. The other end holds a toggle secured by a slipped eye, which takes up maybe 1.5". I suppose that could be a 'last straw".

I must be dense today - I'm not understanding what you mean by a "slipped eye".

Is this a small adjustable eye like on the Whoopie Sling?

Or is it a knot like a slipped bowline?

I get the impression that you are splicing an eye, but "slipped" to me means a knot ?.?.

**Frawg** · 07-09-2009, 19:28

Originally Posted by TeeDee

I must be dense today - I'm not understanding what you mean by a "slipped eye".

Is this a small adjustable eye like on the Whoopie Sling?

Or is it a knot like a slipped bowline?

I get the impression that you are splicing an eye, but "slipped" to me means a knot ?.?.

Sounds like a Humpty Dumpty thing.

It's a buried eye, that behaves like a slip knot or a marlinspike hitch at the end of a line. You bury the standing end instead of the running end.

Here's a pic:

This shows the running end of the static section exiting the constrictor's bury downward to the right. The toggle at the end of the constrictor section is the slipped eye.

HTH

**amac** · 07-09-2009, 19:34

These are a couple of pics of my UCR.

**Frawg** · 07-09-2009, 19:41

Originally Posted by amac

These are a couple of pics of my UCR.

Very clean -- nice!

**amac** · 07-09-2009, 19:41

Originally Posted by Frawg

Frawg, that's grey Amsteel 7/64, correct? Where did you get it?

**TeeDee** · 07-09-2009, 19:41

Originally Posted by Frawg

I hear you, but it just hasn't happend to me. (yet?

) Anyway, that's why I added the rolling hitch -- to ensure that some small amount of contact remains.

In testing it I've deliberately set things loose and then bounced to induce slippage. What happens is that you get a hiccup as the constrictor begins to slide, but then grabs tight again as more of the constrictor segment engages.

Like I said, I double check my suspension every time I climb in. Time will tell if Murphy gets me, I guess.

No - the experiments we performed had nothing to do with slipping under the load due to the load itself. An agent or force exterior to the system can induce the UCR constrictor section to loosen and when that happens it will not grab again - it will fail totally. We even had the buried tail pulled through the constrictor section under the dynamic forces introduced. Can it happen? The probability is probably low, but definitely not zero. How low? Totally unknown and probably unknowable a priori. Would the rolling hitch help? unknown without a lot more experimentation. My guess, based on a lot of experiment with friction knots in a suspension system, is no unless the rolling hitch is initially holding the full force exerted on the UCR, which I have found to not be possible. Once the constrictor section is induced to fail, the motion and dynamic forces will simply be more than a rolling hitch could be expected to hold. Just my guess though.

Originally Posted by amac

I was puzzled for a while by your statement, and finally realized why. I'm not using 2 eye splices, for the exact reason you mentioned...they take up too much room. I tied simple knots. I can slide my constrictor from end to end of the line attached to the tree (is it called the bury-line? or maybe the static line?) I will post pics soon.

Yes, that's what I have tried to get away from, knots on the suspension. In my experience, Knots, like hardware, introduce a weak point and abrasion. Also, if the system depends on tying a knot to ensure system integrity, it is sure that I will forget it one or more times. Kind of like the half-hitch required for the webbing & rings system. I knew that there would be a time I would get sloppy and forget, or just get tired and in a hurry and not tie it properly, etc, etc. Also, it is just one more step in setting the system up.

I pay a penalty in more rope, but in return I get a system that, for me, is super simple, no backup knots and is fool proof in my experience.

Set the constrictor section and it's doesn't move, period. And impossible to slip unless I approach the 2,900 lb rating of the AS-78 which is, for practical purposes, not possible. The hammock fabric will have failed long before the rope and splice limits are even remotely near.

I still have one knot, a cow hitch joining the hammock suspension triangle to the toggles on my MSLS. That's one of the reasons I moved to the modified Whoopie Sling for the suspension triangle - I can replace the sling and hence renew the suspension triangle without having to replace the arc cord on the Bridge. It makes the suspension triangle modular as well as the suspension rope itself. I keep trying to replace the cow hitch also. Unfortunately all of the ways I have devised to date are worse than the cow hitch which can be tied in mere seconds and doesn't add to the weight.