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  1. #1
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    What limits hammock weight limits?

    So I'm a large farm animal... I own two HH's an ultralight backpacker and a Survivor... So per the HH specs, I'm out of the weightclass for the ULB at 250#'s thought I've spent 20-30 nights in it and still have it in my bug out bag. Survivor is a great deal bigger and is supposed to hold up to 350#'s... I recently changed out my Survivors lines for a whoopie sling. Now the lines on my suvivor are a great deal beefier than on the ULB... Sorry, I'm getting to my question.

    What dictates a weight limit for the hammocks usually? Is it the cordage on on the suspension? Would replacing my suspension lines and huggers on the ULB with the suspension from the survivor provide at least anecdotal increase in weight capacity?

    Like I said, I've swung a bunch in the smaller HH but the last thing I want to do is have the suspension snap in the middle of the night with some wind. Thanks in advance.

  2. #2
    Senior Member angrysparrow's Avatar
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    The thickness of the fabric (and/or the number of layers of fabric) is usually the limiting factor.
    I think that when the lies are all told and forgot the truth will be there yet. It dont move about from place to place and it dont change from time to time. You cant corrupt it any more than you can salt salt. - Cormac McCarthy

  3. #3
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    Thanks Sparrow... but the hammock fabric is the same for both... 70D nylon taffeta, 160 x 90 high count. The only difference I did see outside of the cordage on the suspension is (bear with me because it may not make sense) that the where my suspension lines tie into the hammock and screen come together there are two "melted eyelet holes" on the Suvivor and just one on the UL backpacker?

    I did contact HH and ask them what was the item that determined their "weight limits" but never got a response on three seperate occasions.

    Another bit of irony is, I don't believe I know what the whoopie slings are rated for?

  4. #4
    Senior Member angrysparrow's Avatar
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    I wouldn't presume to speak for them as how/why they rate their hammocks. I just mean that the fabric weight is the basis for most occupant ratings, per a wide variety of hammock makers.

    Whoopie slings 'rating' depends on what cording they are made from. Most use 7/64" Amsteel which is itself rated to 1600lbs. But some use 1/8" Amsteel, which is rated to 2500lbs. Not everyone uses Amsteel, though...

    For suspension rating, think of it in terms of the factors that de-rate the cording's strength. Generally speaking, splices are supposed to retain ~90% of the breaking strength of the cording, but I'd call it 80% for application purposes. After that reduction, you calculate the safety factor you want... 5:1 is a commonly held number there. So, 7/64" Amsteel whoopies, spliced correctly, should have a 5:1 safety factor for anyone up to 256 lbs. And 1/8" Amsteel slings would have a 5:1 factor for up to 400lbs. You can of course determine from there whether you'd like to work within either a reduced safety factor, or use larger diameter cording, for your own purposes.
    I think that when the lies are all told and forgot the truth will be there yet. It dont move about from place to place and it dont change from time to time. You cant corrupt it any more than you can salt salt. - Cormac McCarthy

  5. #5
    Senior Member WetRivrRat's Avatar
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    +1 for fabric type/weight(density, not dry weight)
    This isn't my 'go-to' reference, I'm not at a proper PC, so this will have to do, but it does the job. It gives you a pretty decent idea what to expect out of what material and why one might not be the best for you
    http://warbonnetoutdoors.com/hammocking101.php
    cheers
    Last edited by WetRivrRat; 07-25-2012 at 18:56. Reason: adding reference
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  6. #6
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    This is totally unscientific, but from what few failures I have heard of, it has mostly been the tree strap.
    Mike
    "Life is a Project!"

  7. #7
    Senior Member WetRivrRat's Avatar
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    Quote Originally Posted by MAD777 View Post
    This is totally unscientific, but from what few failures I have heard of, it has mostly been the tree strap.
    I've ended up on the ground a couple of times due to tree huggers, but that was more operator error than equipment failure. most 1" straps are rated to 2k lbs.
    me thinks the cases you've heard of were probably someone's excuse for an improper hang..
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  8. #8
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    Thumbs up

    I have read of hammock fabric failures, line failures, knot failures, hardware failures, tree strap failures, and even tree and structural lumber failures via HF over the years, whatever is the weakest link. So, there are weight limits, yes.

    I think it was Angry Sparrow who mentioned using a 1-to-5 rule of thumb for weight to rating safety allowance.

    But understand, you can jeopardize that too, by being too "dynamic" instead of "static" entering your hammock. Think how a bathroom scale shows a much higher weight if you jump on it the least bit.

    Also, the hang angle comes into play. If you hang with less than a 30 degree angle, you are actually putting more effective weight on each line than your actual weight. Think of how you use a lever to increase your weight to move a big rock. It's geometry/physics at work. The same happens based on where you position the sewn loop of a tree strap. Off to the side makes it function like a pulley, which doubles the effective force.

    Knots and bends over sharp corners can reduce the strength of a line by over 50%.

    To make things even more complex, ALL of the above factors come into play all at once.

    Play it safe when it's your backbone hanging over some rock or root. I suspect that's why you're asking for advice.

    Rain Man

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    "You can stand tall without standing on someone. You can be a victor without having victims." --Harriet Woods
    .

  9. #9
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    That all makes sense and I'm careful getting in and getting out, but I still dont' know where the limit is generated between the two models when the hammock material and ridgeline are the same... LIke Isaid, I've emailed HH's and got no answer but maybe Ill try copying and pasting this topic or thread over to the HH forum.

  10. #10
    Senior Member WetRivrRat's Avatar
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    From{http://speerhammocks.com/Tips/Tips.htm#Making}
    "If you are less than 250 pounds: use 1.9 oz/yd2 ripstop or 70 denier 2.2 oz/yd2 taffeta and 1"-wide polypropylene or polyester webbing straps
    ** If you are between 250 and 350 pounds: use Supplex in 2.5 to 3.5 oz/yd2 weights and 1"-wide polypropylene or polyester webbing straps"
    We all know of the original "Walk off the war" thru-hike - but, check out these guys, they're helping folks 'walk off the war' today -
    Donate to help fund gear for the warriors who are coming back home and need help walking off the war!
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