Suspension Horror stories

[silentorpheus]

I will submit this for furthering information on what you asked for.

http://www.hammockforums.net/forum/s...t=lash+whoopie

For those that claim it will not work, it does. Is it stupid because of a lower safety margin? Not in my opinion. The lower safety margin is a risk, one that I am willing to take upon myself after much real world testing that I have done. It has held me up everytime without fail for over 75 nights. I am approximately 200 lbs.

To put in a different perspective; Is everyone driving the safest vehicle on the planet, or are they just stupid for not increasing their survival factor in an auto accident because they want to drive what they like?

Not really an accurate comparison. One could argue that all vehicles sold for use on US highways have passed some measure of safety testing, and are rated as safe and usable for the conditions and situations that are to be encountered on the highways and roads of the country. Instead, it would be like someone taking a moped, vespa, or golf cart on a busy freeway. Can it be done? Sure. Are you guaranteed to crash and die? Nope. Is it a good idea? Definitely not.

I think the argument is not that using lower weight rated arborist rope for hammock suspensions CAN'T work. But rather that it's not recommended, and the risk of it failing, perhaps catastrophically, far outweigh any possible benefit:

- There is no significant weight savings (we're talking less than an ounce for a suspension system)
- There is no significant cost savings (price difference of a few cents per foot - if a dollar or two will make or break your budget, you might want to find a cheaper hobby)
- Neither is easier or harder to procure (all the same places that sell zing-it also sell amsteel and usually dynaglide)

So in essence, the only reason to choose it over a safer option would be likely either out of ignorance, or out of a desire to prove that you can. Folly versus bravado.

Instead the desire, from a community standpoint (a community based around learning and educating on all things hammocking), would be to suggest this not be something that is touted as an advisable option. If you want to choose to push the boundaries and it works for you, by all means. But let's not have new folks who come here looking for advice on how to get started, and what best practices are, going away thinking that this is a perfectly fine option to consider for the beginner.

[SwinginIt]

I think the argument is not that using lower weight rated arborist rope for hammock suspensions CAN'T work. But rather that it's not recommended, and the risk of it failing, perhaps catastrophically, far outweigh any possible benefit:

- There is no significant weight savings (we're talking less than an ounce for a suspension system)
- There is no significant cost savings (price difference of a few cents per foot - if a dollar or two will make or break your budget, you might want to find a cheaper hobby)
- Neither is easier or harder to procure (all the same places that sell zing-it also sell amsteel and usually dynaglide)

So in essence, the only reason to choose it over a safer option would be likely either out of ignorance, or out of a desire to prove that you can. Folly versus bravado.

Instead the desire, from a community standpoint (a community based around learning and educating on all things hammocking), would be to suggest this not be something that is touted as an advisable option. If you want to choose to push the boundaries and it works for you, by all means. But let's not have new folks who come here looking for advice on how to get started, and what best practices are, going away thinking that this is a perfectly fine option to consider for the beginner.

Very well said.

[Boston]

1.75mm lash-it =500lbs break
2.2= 650lbs break

@150 lbs in the hammock
1.75mm=3.3:1 safety margin
2.2mm=4.3:1 safety - and within the 4 or 5 to 1 recommended earlier

the math says "go for it" with the 2.2- just keep an eye on line integrity, there is not a lot of safety margin to spare be sure you have a soft spot just in case.

Whoopies slings reduce line strength to 60-80%.

So the real STATIC factor of safety is:

2.2 = 2.6 - 3.46
1.7 = 2 - 2.66

Now, account of wear and dynamic loading (entering/exiting the hammock, bouncing while moving around), I'd bet good money the whoopies you make wont last very long.

[SwinginIt]

Whoopies slings reduce line strength by 60-80%

Where'd you get that number from? Knots reduce line strength 1/3-1/2 and splices are much stronger than knots. At least that's what I learned. Do you have a link to where you got that info?

[silentorpheus]

Where'd you get that number from? Knots reduce line strength 1/3-1/2 and splices are much stronger than knots. At least that's what I learned. Do you have a link to where you got that info?

Methinks they have it backwards. As per documentation from Samson Rope's website:

http://www.samsonrope.com/Documents/...UG2012_WEB.pdf

properly constructed whoopee slings using amsteel retain 60% of the overall breaking strength that the line is rated to. So the splicing/sling de-rates the rope by roughy 40%.

Assuming you can apply that same percentage equally to Zing-it/Lash-it, the 1.75mm would have an average breaking strength of 300lbs, and the 2.2mm an average breaking strength of 390lbs.

[gmcttr]

Whoopies slings reduce line strength by 60-80%...

Whoopies derate amsteel to 80-90% of it's listed rating.

Yes, I'm aware that Samsom has 60% on one splicing .pdf, but their engineers have stated the true figure at 80%+ and testing to destruction by a couple of HF members places the number higher if I recall correctly.

[silentorpheus]

Whoopies derate amsteel to 80-90% of the it's listed rating.

It would seem that there is a rather large swath of opinion on exactly what percentage the line is derated.

Though I did just do a search, and read in some old posts that through correspondence with Samson, they suggested that 60% might be conservative, and likely it's closer to 80%.

But all of that is dependent on splicing to proper specs - I know when I make whoopies I always forget what the proper lengths are supposed to be, so I just do a quick search, and take an average of what has been suggested before. Hardly scientific.

[SwinginIt]

Whoopies derate amsteel to 80-90% of the it's listed rating.

Yes, I'm aware that Samsom has 60% on one splicing .pdf, but their engineers have stated the true figure at 80%+ and testing to destruction by a couple of HF members places the number higher if I recall correctly.

Now that makes more sense and is in line with what I believed it to be.

[SwinginIt]

It would seem that there is a rather large swath of opinion on exactly what percentage the line is derated.

Very true. I was taught in firefighting school and in training for high angle rescue that knots derate a rope by 1/3, but everyone here says 1/2.

[silentorpheus]

Yes, I'm aware that Samsom has 60% on one splicing .pdf, but their engineers have stated the true figure at 80%+ and testing to destruction by a couple of HF members places the number higher if I recall correctly.

That makes sense to me. One can always assume that the company that makes it is going to lowball things, in the name of mitigating potential litigation.

In the end it doesn't much matter. People are going to do what they are going to do - and if someone tries it and it works, no amount of showing facts and statistics is going to convince them that they're the exception not the rule. For every fact or figure that exists, there's going to be someone that can say "I did it, and never had a problem".

The responsible thing to do, though, is to make sure that when and if someone decides to do something that flies in the face of conventional wisdom, even if they are successful, there is at least some mention of the fact that "Hey, I accept that this isn't considered safe, I proceeded at my own risk, and it worked for me - make your own decision".