The truth about dynaglide and safety...

[nothermark]

I think you will find it makes a difference where you put the knot on a loop used for a larks head or prussic. I always try to put the know where the rope has been wound over something as the winding takes some of the strain. On a spliced loop it is not as big a deal.

[TheIrishmanHangeth]

There is what you mention, plus: what about the Lark's Head that cinches down on the hammock end knots or cinches down after the rope comes out of an end channel? Is that a knot, does it count as one? Because I think I remember a thread here where some one showed than any kind of knot vastly degraded Amsteel far more than we are used to thinking happens. I think it was some huge % decrease in strength, like 60-80%. ( but I see in this thread that WBG is showing more like 50% with a fig 8 knot, a more reasonable %)

If this were the case, then, even 7/64 wouldn't have the "necessary" safety ratios as that simple larkshead would drop it to less than 800 pounds along with the 10% for the splice. It seems very unlikely that a larkshead would decrease the strength by that much.

[TheIrishmanHangeth]

Apologies in advance, but to me, you hit the nail on the head. Twice.



Not just math, but "simple number crunching." Scary.



Agreed. Definitely hang over ground so soft you might as well tent.

I'm an ex-caver and did some "vertical caving" in my younger years. I know of cavers who died, were injured, or had very scary experiences doing analyses like this one.

And in this case, for what? To save a few grams?

Rain Man

.

If we were talking about life or death scenarios here, you would be absolutely correct, but we're not. We're talking about hanging in a static position at most a few feet off the ground. Hardly the same circumstances that you were involved in with spelunking. If I was climbing a rock face then I would most certainly not be presenting this scenario as I would want as much safety ratio as possible for the weight. But in the case of hammock hanging if you are practicing proper hanging principles the odds of something causing a line with 1000 pound breaking strength to just snap with no other prior damage being present is slim to none. Plus, lets say it does, if you're again practicing proper and safe hanging practices you won't be hanging over anything that would cause an injury beyond the superficial. If you are then obviously more safety measures should be taken.

And FWIW, math, as well as number crunching, is what everything within hammock hanging is based upon. The only reason I didn't have to do any math is because someone had already done that and was kind enough to put it into an easy to use format(i.e. the ultimate hang calculator).

[TheIrishmanHangeth]

Good point BB, i think the larks head that attaches a whoopie to the hammock would decrease strength some as there's a somewhat sharp bend in the rope there...no telling how much that degrades the strength of a whoopie, but i'd imagine it does have some effect.

I would think too that since, typically anyway, a whoopie sling is larksheaded around something like a whipped hammock end, that the strength would not be degraded anywhere near as much as an actual knot since the bend angle is nowhere near as extreme.

[nothermark]

YMMV but in my mind hanging my hammock *is* the same as a life and death situation.

[SilvrSurfr]

YMMV but in my mind hanging my hammock *is* the same as a life and death situation.

Yep, one sharp rock and even an 18-inch fall could be disastrous, especially if you're far from medical attention. I've had my fair share of concussions (no comments from the peanut gallery). In a wilderness situation, the confusion from the concussion could kill you just as easily as the blow to the head.

[TheIrishmanHangeth]

Yep, one sharp rock and even an 18-inch fall could be disastrous, especially if you're far from medical attention. I've had my fair share of concussions (no comments from the peanut gallery). In a wilderness situation, the confusion from the concussion could kill you just as easily as the blow to the head.

So don't hang over a sharp rock. That's along the same lines as don't hang under widow makers. Site selection is just as important, if not more so, than what you're using for suspension.

[BillyBob58]

So don't hang over a sharp rock. That's along the same lines as don't hang under widow makers. Site selection is just as important, if not more so, than what you're using for suspension.

Especially in the Rockies, I have had more than a few sites where it was impossible to avoid rocks, sharp or otherwise, and have 2 usable trees and be able to avoid the dangerous trees. Sometimes not many usable trees not near dangerous trees, but always lots of rocks.

[TheIrishmanHangeth]

Especially in the Rockies, I have had more than a few sites where it was impossible to avoid rocks, sharp or otherwise, and have 2 usable trees and be able to avoid the dangerous trees. Sometimes not many usable trees not near dangerous trees, but always lots of rocks.

I can definitely understand that, and I've hung over rocks before as well but not sharp ones that would cause me to have a life threatening injury. To each their own, but I'll sleep on the ground before I hang over something that could potentially kill me, regardless of what suspension I'm using.

[SilvrSurfr]

So don't hang over a sharp rock. That's along the same lines as don't hang under widow makers. Site selection is just as important, if not more so, than what you're using for suspension.

Guess you haven't hiked the Appalachian Trail much. I would rather tell someone "make sure your suspension provides a minimum 5:1 safety ratio," than imply that 400 lb. men can safely use Dynaglide as their suspension.

I do have one hammock with Dynaglide suspension, but it doesn't come out to play in rocky areas. Hunting for a non-rocky spot to hang my hammock on the AT would defeat the purpose of having a hammock in the first place. I'd be just like ground dwellers, only instead of trying to find a place to put my shelter, I'd be looking for a rock-free location to hang my hammock and its inadequate suspension.

I have heard of people trying Zing-It or 1.8 mm tech line as their suspension (we don't hear much from those folks, probably because the results were not too good). I weigh 160 lbs., so I feel pretty comfortable in most situations with Dynaglide since I have better than 5:1 safety ratio. However, 7/64" Amsteel is my suspension of choice when the terrain is not particularly kind to people looking for rock-free zones.