The truth about dynaglide and safety...

[TheIrishmanHangeth]

Saying where the weights and info was taken from, adding links so that others whom may question those can be seen for their own eye's makes it easier to deal with. Example as too the given weight rating was taken from where? Which source? Type of deal. Like sampson rope, or west marine, or x company, but give the link to it. Info taken from the book the Ultimate hang and you said you took it from there was fine, I was just talking about other web sites where the other info can be found.

I am not sure about the percentage that each type of splice, or and splices de-rate line.

Thats all I was talking about.

That's what I figured. Well here is some interesting news. As I said before Sgt. Rock stated in a video that splicing retains 90% of the rope strength. Well this is straight from samson-http://www.samsonrope.com/Documents/...UG2012_WEB.pdf

It says at the very top of the page before the whoopie sling instructions that a whoopie sling retains 60% of rope strength. I'm wondering now if possibly Rock was mistaken. We all know him to be a very thorough guy so I'm wondering if maybe this publication wasn't around when he first started messing around with all this stuff. Either way, it deserves some thought.

[TheIrishmanHangeth]

Okay so I went ahead and pm'd Sgt. Rock and had a short convo about splicing and line strength and was gracious enough to do a quick search and found a page on the marlow ropes website that state that splicing does indeed retain 90% of the line strength-http://www.marlowropes.com/splicing-instructions.html-

He also provided a link to a PDF file showing strength retention for various splicing projects including the whoopie sling which is stated to retain 85-90%. -http://www.orosha.org/pdf/grants/osu/runninglines.pdf- hopefully that clears things up a bit more

[SilvrSurfr]

Okay so I went ahead and pm'd Sgt. Rock and had a short convo about splicing and line strength and was gracious enough to do a quick search and found a page on the marlow ropes website that state that splicing does indeed retain 90% of the line strength-http://www.marlowropes.com/splicing-instructions.html-

He also provided a link to a PDF file showing strength retention for various splicing projects including the whoopie sling which is stated to retain 85-90%. -http://www.orosha.org/pdf/grants/osu/runninglines.pdf- hopefully that clears things up a bit more

Interesting info on that Marlow website. I think one page in particular sums up my feelings on this topic.

http://www.marlowropes.com/technical...roperties.html

"Working Loads: Marlow Ropes specify a minimum breaking load (or sometimes an Average Breaking Load). It is the responsibility of the user to determine an appropriate factor of safety and safe working load. This factor of safety must be determined after considering all the risks, the strength reducing factors, and the expected life of the rope."

And then they list all the factors affecting safety:

Static load
Dynamic loads
Strength reduction due to splices / knots
Strength reduction due to sheaves
Strength reduction due to Bending
Fatigue over expected life of rope
Consequences of rope failure
Frequency of inspection
Experience / training of operators
Exposure to chemicals
Exposure to UV radiation
Exposures to high temperatures
Intended life of rope
Abrasion

That's some common sense advice, which to me, says basically that if you are making decisions using only manufacturer breaking strength specs, you are not using your brain. I'm sticking with minimum 5:1, and usually 10:1 safety ratios.

[TheIrishmanHangeth]

Interesting info on that Marlow website. I think one page in particular sums up my feelings on this topic.

http://www.marlowropes.com/technical...roperties.html

"Working Loads: Marlow Ropes specify a minimum breaking load (or sometimes an Average Breaking Load). It is the responsibility of the user to determine an appropriate factor of safety and safe working load. This factor of safety must be determined after considering all the risks, the strength reducing factors, and the expected life of the rope."

And then they list all the factors affecting safety:

Static load
Dynamic loads
Strength reduction due to splices / knots
Strength reduction due to sheaves
Strength reduction due to Bending
Fatigue over expected life of rope
Consequences of rope failure
Frequency of inspection
Experience / training of operators
Exposure to chemicals
Exposure to UV radiation
Exposures to high temperatures
Intended life of rope
Abrasion

That's some common sense advice, which to me, says basically that if you are making decisions using only manufacturer breaking strength specs, you are not using your brain. I'm sticking with minimum 5:1, and usually 10:1 safety ratios.

Why are manufacturers spec not to be trusted??? While it is most certainly the responsibility of the user to make sure they feel safe using a certain piece of equipment, provided the proper gear inspections have been done there is no reason that the manufacturers specs can't be followed with confidence, that's what they were established for. On the flipside of that, no amount of safety factor ratio can make up for a lack of gear inspection to make sure everything is in good working order.

I'm curious why the folks that always tote about the 5:1 or 10:1 ratios feel the need to do so. You prefer to use those ratios, that's fine, it doesn't mean that people who don't are doing it wrong or are doing things in an unsafe manner. You obviously feel hammock hanging is a life or death thing, I don't. And I'm not going to put myself in a hanging situation where it is life or death, I'll sleep on the hard ground first. That's how I justify the use of dynaglide and lighter weight components than normal. You don't see it that way. That's okay. I don't understand why there is this need to chastise the people who don't use conventional safety ratios as being irresponsible.

[SilvrSurfr]

I don't understand why there is this need to chastise the people who don't use conventional safety ratios as being irresponsible.

By no means did I mean to chastise. I was impressed by Marlow's detailing of all the factors affecting rope choice. I felt it justified my 5:1 or 10:1 preference. You could read the same information and come to a different conclusion.

I don't have a problem with Dynaglide for my own setup, but I weigh 165 lbs. I'd recommend heavier people use 7/64 or 1/8 Amsteel to get the same warm fuzzy 5:1 ratio.

WV feels comfortable with a 3:1 ratio, but I can't understand his math or what type of rope he's using - he weighs less than me and is definitely getting 5:1 on Dynaglide.

[TheIrishmanHangeth]

By no means did I mean to chastise. I was impressed by Marlow's detailing of all the factors affecting rope choice. I felt it justified my 5:1 or 10:1 preference. You could read the same information and come to a different conclusion.

I don't have a problem with Dynaglide for my own setup, but I weigh 165 lbs. I'd recommend heavier people use 7/64 or 1/8 Amsteel to get the same warm fuzzy 5:1 ratio.

WV feels comfortable with a 3:1 ratio, but I can't understand his math or what type of rope he's using - he weighs less than me and is definitely getting 5:1 on Dynaglide.

I think that is because he uses a different suspension system. If I recall correctly it was earlier in this thread that he stated he hangs a taut ridgeline and then attaches his hammock via prusiks( or something similar I think). If that is the case he very well could be getting that 3:1 ratio due to the hanging force multiplier from having less than a 30 degree angle.

And I wasn't meaning to single you specifically out with the chastising remark(sorry if it came across that way), it just seems sometimes that in general those who follow the normal safety standards look down on those who don't. I'm not pointing fingers at anyone in particular or even saying that's how it is meant, just how it comes across sometimes. No harm no foul, I'm a resilient ginger and don't offend easily

[WV]

That's good to know, SS. I meant I'd like at least a 3:1 safety factor, but I wasn't sure what my Dynaglide suspension was actually giving me.

[SGT Rock]

FWIW, I figured I would stay out of this because in my experience over the last 20+ years of internet hiking (where people that know it all on the internet post about all they know) there have been lots of things that were going to get everyone killed. I remember when Sil-Nylon was a huge controversy back in the 90's because it was "highly flammable" and would (according to the internet know-it-alls) eventually result in people dying in sil-nylon tarps and tents from stove fires. People with base weights under 20 pounds were a danger to themselves because they were not ready for "real weather", etc, etc etc. I looked at all the data and made an informed decision, and continue to experiment with what I think are logical choices. I don't expect to use my hammock suspension for a safety line when working off a suspension bridge so why would I need a 10:1 ration for what holds my bed up? Lots of people can "what if" the different scenarios as to how I am going to put that stress on my hammock, but in 13 years of hammocking I haven't seen those coming up yet. I imagine it is the same sort of mentality that what-if's all the reasons you might get bit by a snake or bear when hiking in the Smokies. I still hike there and I've never had an occasion where I felt that was going to happen either. But I still see bear bells and bear spray canisters on the tourists ever year.

So people start posting about the real data on danaglide ropes and splices. Internet know-it-alls will chide you for saving a few grams and forsaking safety which will eventually get you killed if you do "real hiking" long enough. My guess is in 20 years no one will remember caring about these things when no dynaglide users are dead. Probably, like the deadly sil-nylon, these things may even become a norm someday. Imagine that.

So, read the data, make an informed decision, and ignore the what-ifers and the internet know-it-alls.

[TheIrishmanHangeth]

So, read the data, make an informed decision, and ignore the what-ifers and the internet know-it-alls.

Well said Sgt. Rock, that is all I was trying to convey. I hope along the way I did not make anyone feel like I was trying to force the idea of using dynaglide on them or that if you're not using it you're just being a "nervous nelly". Definitely HYOH and if ya don't feel comfortable hanging on dynaglide, don't. Doesn't matter if you weigh 400 pounds or 100 pounds. If you're worried the suspension will snap the whole time you're in the hammock you won't have an enjoyable time. And having fun is the whole reason we do this. Well, that and so we don't have to sleep with rocks in our backs

[SGT Rock]

FWIW I did a review a couple of years ago for a manufacturer a d he didn't care forbthe review. This led to an exchange of emails about hammock design. I bring this up because this manufacturer uses big honking ropes and claims their hammocks are rated to 350 pounds. But during that exchange he revealed the line strength to be less than 1200 lbs. So that is between a 3:1 ratio and a 4:1 ratio. As far as I know, no one has been hurt or died from the thousands of hammocks I imagine they have out in the field. So WV using a 3:1 ratio is probably safe. I've been as low as about 2:1. But it did break after about 800 miles of hiking and I'm currently at about 5:1 with no worries afte r 1000 miles on that type suspension.