DIY hollow core polyester rope ??????????

**onetearless** · 03-29-2016, 15:36

I went to a big box store today and bought some braided polyester sheathed rope. I cut a section and removed the core and spliced a CL. I pulled on it pretty hard seems tough enough. Anyone care to take a guess at how much over all strength I will loose to this technique. Package says 230 lb safe working load. Thats like 2300 breaking strength (I think). I am planing on using it for guy line on my hammock stand. So it will have to hold a bit of weight. I know I should get some high end registerd trademark cleverly branded nearly task specific dynaglide or amsteel and call it a day but I like to experiment. It is my understanding that polyester is strong and low stretch. ANY THOUGHTS???????????????????????

**Eidson** · 03-29-2016, 15:55

Safe Working Load figures typically have another variable figured in to them..a safety factor # or safety ratio. The safety factor number is usually defined as a 10 (or a 10:1 ratio)if equipment could pose a life risk. A lot of people will generally assume a safety factor number of 4 - 6 for general non-life threatening purposes. A general SWL calculation is MBS (minimum break strength) / Safety Factor = SWL.
So assuming the manufacturer used this semi-standard figuring, the breaking strength would likely be half of what you're figuring. Plenty of companies will rate their line/rope differently, so it's always hard to definitively say.

I'll leave it to the advice of others as to whether or not you should use this. You'll likely receive plenty of advice.

**onetearless** · 03-30-2016, 10:29

Originally Posted by Eidson

I'll leave it to the advice of others as to whether or not you should use this. You'll likely receive plenty of advice.

Hmmmmmmmm?

Thx for your help Eidson. Looks like everybody else is playing it safe. Probably smart! My team of cracked out lawyers is using very sophisticated tech to mine HF for potentially actionable misrecommendations as we speak.

Heh.

**Eidson** · 03-30-2016, 10:47

I'm kinda of surprised that others haven't chimed in as well. I'm used to seeing the opinions come out quickly and "you're going to die" get mentioned anytime someone wants to push the limits of cordage. I try to avoid sharing my personal opinions simply because they're just that, personal.

Here was an interesting link that I came across and saved from the forums when I was contemplating a hammock stand. You'll be able to find a lot of figures in this thread if you have the time to look it over.

https://www.hammockforums.net/forum/...uylines-stakes

I personally haven't spliced any cord like you've mentioned, so I can't comment on the how it handles or help there. I do think that you'll have much better luck with polyester versus nylon cordage.

I'm conscious that I am overly cautious in any cordage/line used anywhere in my hammock suspension, which again makes me hesitate to give "recommendations" . I've never had a failure anywhere, but I also use the "high end registerd trademark cleverly branded nearly task specific dynaglide or amsteel" and go with line that is well beyond the limits of my weight (around 150). One advantage with this line is that the manufacturer openly publishes all the pertinent stats and information with their line. This avoids any guessing on how it is actually going to hold up.
On the flip side, I have a stubborn friend who refuses to use anything other than cheap 550 nylon paracord, tied with knots, in his suspension. He's around 210 and has inexplicably used the stuff for years without issue (other than stretching).

I personally would hesitate, but that's just me an my over-cautiousness. If anything I'd give it a good test run before fully committing.

**Pyrogen** · 03-30-2016, 11:29

I made a CL out of some hollowed out rope and hung from it one night while waiting on my AmSteel to come in the mail. It worked, I didn't fall, but ultimately, AmSteel is light and cheap enough to play around with, and proven to support well over my weight. I wouldn't trust cored out poly rope for a whoopie sling as I don't believe it constricts enough to vice-grab the line as it should, but for a locked brummel dogbone or CL, it worked decent to quickly and cheaply prototype a concept before moving on to AmSteel.

**GreatBigDave** · 03-30-2016, 11:47

What kind of hammock stand? Are these guys supporting you weight in the hammock? I would guess that you took most of the line's strength out with the core. I would use knots with cored line.

**Pyrogen** · 03-30-2016, 11:54

Wall-bolts and carabiners. It supported my weight just fine larks-headded around a gathered end. I'd bet you're right, the line's strength definately went down with the loss of the core to compress upon, but to make up for it, It was doubled back upon itself. Again, only used it for one night and prototyping. (Also, at the time, because it was a critical part, I had my mattress beneath me in case something failed, so I wouldn't crack my duff. It held, but I wouldn't trust it with out the failsafe.

That having been said, I need a hammock stand. To be honest, I kind of trust the hacked up poly rope more than my 1970's wall studs.

**onetearless** · 03-30-2016, 14:10

[QUOTE=Eidson;1607551]

Here was an interesting link that I came across and saved from the forums when I was contemplating a hammock stand. You'll be able to find a lot of figures in this thread if you have the time to look it over.

https://www.hammockforums.net/forum/...uylines-stakes

This was an interesting thread. Thx. Their calculations depend on a vertical pole. I've got the supports at an angle like the handy hammock or the No Ground system. I wonder if that changes anything. As for the forces on the guy lines looks like the working load of the original line would be ok, but core removal is potentially too big an unknown to calculate. I am possibly willing to give it a try and see. Like the check out clerk at the big box store said "rope is rope". Well . . . until you completely modify it to suit your completely unresearched and fantastic criteria.

**Pyrogen** · 03-30-2016, 14:33

A Home Depot clerk is the last person I'd take critical advice from. If you're going to test this out, do it above a mattress please, or at the very least, hang low. Last thing you want to wake up to is a shattered coccyx.

**Phantom Grappler** · 03-30-2016, 15:17

The core might be strongest part. Suppose the core and the sheath each give half of ropes strength, then when you remove the core--the rope is not half as strong--you've changed the structure of the rope and it is now less than half as strong. This is all guessing by me and your project might work great. If it was me, I'd use amsteel, that's already hollow. Or maybe spyderline with no modifications. Good luck and hang your own hammock as it suits you!