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  1. #1
    New Member resnikov's Avatar
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    ridgeline and soft shackles

    At the moment I have a DD frontline and use a continuous loop through the channel on the frontline, then I attach my whoopie slings using a soft shackle to the continuous loop. I have been thinking about putting in a ridge line like suddenfromaspudden has done here.

    Now my question is would the soft shackle cope with the ridge line attached as well or is there too much force now in 3 directions for it? Thought I would ask before I go out and try it.

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  2. #2
    Senior Member Roe Ring's Avatar
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    Somebody please correct me if I'm wrong here:

    If the load on your hammock is fixed, i.e. your body weight, then without a ridgeline, all of the load is transfered to you whoopie sling through the soft shackle. If you add a ridgeline, then the load is divided between the whoopie sling and the ridgeline, but the sum of the load will remain the same. The load is the same but it is distributed differently. In this situation, the force transfered from your continuous loop onto your shackle will remain the same because that is the load applied but the ridgeline and the whoopie sling are sharing that load and are putting less strain on the shackle at their connecting points.

    In short, it shouldnt affect the shackle at all.

    Clear as mud

    Mark

  3. #3
    turnerminator's Avatar
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    Soft shackles (tied with a lanyard/diamond knot) are rated to 175% (Opie or Nacra tested them to failure) of the BS of the line so will be plenty strong enough.

    Hang in peace mate

  4. #4
    New Member resnikov's Avatar
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    Excellent news chaps. Now just need time to get out and try it.
    resnikov

    "You can do loads in 12 minutes. Suck a mint, buy a sledge, have a fast bath"

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  5. #5
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    Quote Originally Posted by Roe Ring View Post
    Somebody please correct me if I'm wrong here:

    If the load on your hammock is fixed, i.e. your body weight, then without a ridgeline, all of the load is transfered to you whoopie sling through the soft shackle. If you add a ridgeline, then the load is divided between the whoopie sling and the ridgeline, but the sum of the load will remain the same. The load is the same but it is distributed differently. In this situation, the force transfered from your continuous loop onto your shackle will remain the same because that is the load applied but the ridgeline and the whoopie sling are sharing that load and are putting less strain on the shackle at their connecting points.

    In short, it shouldnt affect the shackle at all.

    Clear as mud

    Mark
    The tension in your whoopie is a function of the hang angle (relative to the end of the hammock) and the weight in the hammock.

    Now, a ridge line will influence the hang angle, but it will not share any of the load. Realistically if you are using a SRL, you are increasing the load in your suspension. Reason being, the SRL is only working when the suspension hang angle is less than your hammock hang angle (otherwise your SRL will be slack).

  6. #6
    Senior Member Roe Ring's Avatar
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    Quote Originally Posted by shlabbo View Post
    The tension in your whoopie is a function of the hang angle (relative to the end of the hammock) and the weight in the hammock.

    Now, a ridge line will influence the hang angle, but it will not share any of the load. Realistically if you are using a SRL, you are increasing the load in your suspension. Reason being, the SRL is only working when the suspension hang angle is less than your hammock hang angle (otherwise your SRL will be slack).
    Just found this thread - http://www.hammockforums.net/forum/s...4&postcount=95

    Agreed that the RL cant share the load, the reactions at each joint cancel each other out. Still not sure if the addition of a RL under tension can increase load on the Whoopie sling. Forces must be in equilibrium, therefore the reaction force in the sling can only be equal to the applied force which is the hammock load.
    Last edited by Roe Ring; 06-06-2011 at 16:26.

  7. #7
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    You are absolutely right, the forces must sum to zero if the hammock is static.

    When I said "increased" I meant for a given hang angle there would be more tension in the suspension when using a SRL than if you hung the hammock without an SRL at the same angle. I say that because if you are truly using the SRL it would be under some degree of tension. The SRL is in tension when, using the other post for example, alpha (suspension angle) is less than beta (hang angle). Considering the force in the suspension line is weight/2sin(theta), this expression "increases" as theta decreases.

  8. #8
    Senior Member Roe Ring's Avatar
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    Thanks shlabbo,

    I can't quite get my head around how a load, say 200lb, applied centrally, can result in more than 100lb at each tree. Is it because the 200lb is a vertical component being supported at an angle (alpha) which has both horizontal and vertical components? I think I'd need to work my way through the calcs. Its been a while!

  9. #9
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    Since the ridge line does not bear any load or need to in the hang, common sense dictates that when attaching the supporting ropes from the trees to the hammock their angle when weight is applied to the hammock will be such that the ridge line has minimal tension. Enough tension so that whatever you need to hang from it will not sag. Excessive tension will only add stress to the shackle and ridge line risking failure of either. If the ridge line fails then of course whatever is hanging from it (net, lantern, shoes etc.) will fall. If the shackle fails then you and the hammock will fall to the ground. So make sure the shackle (either soft or metal) is up to the task and hang intelligently. You don't need much physics for that. On the other hand this new disintegrator gun I am designing is a real mind bender not to mention the difficulty in getting test subjects

  10. #10
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    Quote Originally Posted by Roe Ring View Post
    Thanks shlabbo,

    I can't quite get my head around how a load, say 200lb, applied centrally, can result in more than 100lb at each tree. Is it because the 200lb is a vertical component being supported at an angle (alpha) which has both horizontal and vertical components? I think I'd need to work my way through the calcs. Its been a while!
    Exactly. Do the math, its amazing the forces that are present at very acute hang angles. Its not terribly intuitive.

    @jtbradyl,
    In my practice, I dont try to fiddle with the hang angle to get minimum tension in the ridge line. The whole reason I use a ridge line, is so that the fiddle factor of hanging the hammock goes away. Using the ridge line to hang things is a bonus, but, its primary reason for me is to take a load and make setup easy.

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