Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 39
  1. #21
    Senior Member TiredFeet's Avatar
    Join Date
    Sep 2007
    Location
    MD
    Hammock
    TeeDee Bridge Hammock
    Tarp
    Customized JRB
    Insulation
    Down or IX
    Suspension
    Whoopie Slings
    Posts
    1,099
    Images
    34
    Quote Originally Posted by Schneiderlein View Post
    I am not sure if there was an implication that structural ridgelines are good or bad in Youngblood's posts. I think what Youngblood posted is very helpful and lets the hanger make a smart decision about their suspension system and the kind of trees they hang from.
    I didn't say that either.

    And I agree that his posts are helpful. I just don't think that he gave the full story in considering modern ropes.

  2. #22
    Senior Member TiredFeet's Avatar
    Join Date
    Sep 2007
    Location
    MD
    Hammock
    TeeDee Bridge Hammock
    Tarp
    Customized JRB
    Insulation
    Down or IX
    Suspension
    Whoopie Slings
    Posts
    1,099
    Images
    34
    Quote Originally Posted by Schneiderlein View Post
    ...

    I plan on trying out a structural ridgeline to see if I like it. The graph tells me that the benefit of being able to attach at a lower point comes at the cost of a reduced safety margin. ...
    Actually the reduction in the safety margin is marginal with modern ropes. Modern ropes using modern fibers can comfortably hold more than you can subject them to hanging a hammock even with a structural ridge line.

    That is all I was trying to show. By solely emphasizing the forces involved and not discussing the role of modern ropes in handling the forces, I felt that Youngblood was maybe scaring people into thinking that the ridge line wasn't safe using modern ropes, where it actually is quite safe.

  3. #23
    Senior Member
    Join Date
    Jan 2008
    Location
    Columbia, SC
    Posts
    631
    Images
    11
    I'm sorry if I misinterpreted your post, TiredFeet.

    I think the reduction in safety margin can be quite substantial, if you can increase your force from 200lbf to 800lbf just by attaching lower. That reduces your safety factor from 6 to 1.5 if the weakest link in your suspension system is rated at 1,200lbf, as is the case with my straps. Even with high-tech straps and rope, I'd still be concerned about taking down a tree.

    I think what Youngblood posted actually applies to hanging your hammock whether you use a structural ridgeline or not. The forces increase dramatically as the angle between suspension line and tree becomes closer to 90 degrees. Withou a structural ridgeline, you wouldn't hang that way because it would be very uncomfortable. As I see it, the only potential problem with a structural ridgeline is that it does allow you to hang that way in comfort, but it doesn't mean you have to. So, they are not inherently unsafe, but you should use proper caution.

    As I said, I have never used one, so maybe Youngblood can clarify this?

  4. #24
    Senior Member NCPatrick's Avatar
    Join Date
    Oct 2006
    Location
    Winston-Salem, NC
    Hammock
    WB Traveler
    Tarp
    Custom OES tarp
    Insulation
    JRB Down UQ/TQ
    Suspension
    Whoopie slings
    Posts
    8,797
    Images
    40
    Are we factoring in that trees also get wider at the bottom? I can't remember..


    "Civilization is the limitless multiplication of unnecessary necessities."
    - Mark Twain
    “I go to nature to be soothed and healed, and to have my senses put in order.”
    - John Burroughs

  5. #25
    Senior Member
    Join Date
    Jan 2008
    Location
    Columbia, SC
    Posts
    631
    Images
    11
    Quote Originally Posted by NCPatrick View Post
    Are we factoring in that trees also get wider at the bottom? I can't remember..
    Not yet, but that's a great idea. I will update my finite element model, which also accounts for the moment on the tree roots being reduced the lower you hang...

  6. #26
    Senior Member NCPatrick's Avatar
    Join Date
    Oct 2006
    Location
    Winston-Salem, NC
    Hammock
    WB Traveler
    Tarp
    Custom OES tarp
    Insulation
    JRB Down UQ/TQ
    Suspension
    Whoopie slings
    Posts
    8,797
    Images
    40
    Also need to account for the types of trees (acidity of the soil(?), tendency of certain trees to have shallow roots vs deep roots, whether it's windy out -- which way is the tree leaning, swaying factors, age of the trees, health of the trees, etc.).

    Just kidding Youngblood. I do see what you're saying.


    "Civilization is the limitless multiplication of unnecessary necessities."
    - Mark Twain
    “I go to nature to be soothed and healed, and to have my senses put in order.”
    - John Burroughs

  7. #27
    Senior Member
    Join Date
    Jan 2008
    Location
    Columbia, SC
    Posts
    631
    Images
    11
    You are kidding now. But wait just a few minutes and someone will post that the moment actually remains the same as the force becomes more perpendicular to the tree.

    **** engineers (I'm one of them).

  8. #28
    Senior Member NCPatrick's Avatar
    Join Date
    Oct 2006
    Location
    Winston-Salem, NC
    Hammock
    WB Traveler
    Tarp
    Custom OES tarp
    Insulation
    JRB Down UQ/TQ
    Suspension
    Whoopie slings
    Posts
    8,797
    Images
    40
    Well, it'll certainly enhance our collective knowledge!


    "Civilization is the limitless multiplication of unnecessary necessities."
    - Mark Twain
    “I go to nature to be soothed and healed, and to have my senses put in order.”
    - John Burroughs

  9. #29
    Senior Member
    Join Date
    Dec 2007
    Location
    Doraville, GA
    Posts
    946
    Images
    23
    Quote Originally Posted by TiredFeet View Post
    Youngblood - I asked my girlfriend about your posts on the ridge line. Her reaction was that you are totally correct on the forces involved, but that she thought you also missing something.
    With a structural ridgeline, for any particular span you have a range of attachment heights where you can achieve the same hammock sag with the hammock the same distance above the ground. When you attach lower on the attachments you are using more force than you would if you attached higher. Beyond more force not being a good thing where reliability and possible damages to whatever it is attached to is concerned, there is another issue.

    When you tie lower, the hammock will also drop further when it is loaded versus when you tie higher because of the forces and geometry involved. This extra drop when the hammock is loaded does not make hanging a hammock easier, it does just the opposite and it can make hanging tarps close to the hammock more trying as well. I can create diagram(s) or you can try it yourself if you are interested, it is pretty easy to see when you know what to look for it. For those that want to analyse it, it is just a geometry problem that involves the cosine and tangent of small angles versus larger angles.

    My advise is to hang 'em high. This creates less stress on everything involved and you will have less drop when the hammock is weighted. And yes, when you do that you don't need a structural ridgeline as much to set the sag and you may discover that you don't need it at all.
    Youngblood AT2000

  10. #30
    Senior Member
    Join Date
    Dec 2007
    Location
    Doraville, GA
    Posts
    946
    Images
    23
    Quote Originally Posted by Schneiderlein View Post
    I think what Youngblood posted actually applies to hanging your hammock whether you use a structural ridgeline or not. The forces increase dramatically as the angle between suspension line and tree becomes closer to 90 degrees. Withou a structural ridgeline, you wouldn't hang that way because it would be very uncomfortable. As I see it, the only potential problem with a structural ridgeline is that it does allow you to hang that way in comfort, but it doesn't mean you have to. So, they are not inherently unsafe, but you should use proper caution.

    As I said, I have never used one, so maybe Youngblood can clarify this?
    You have it figured out but we have always used the horizon as the zero angle reference instead of the vertical axis.
    Youngblood AT2000

  • + New Posts
  • Page 3 of 4 FirstFirst 1234 LastLast

    Similar Threads

    1. explain nacarabiner to me?
      By ShadowAlpha in forum Suspension Systems, Ridgelines, & Bug Nets
      Replies: 9
      Last Post: 01-13-2011, 19:22
    2. who can explain..down and moisture
      By Anorak84 in forum General Hammock Talk
      Replies: 14
      Last Post: 01-07-2011, 12:55
    3. Can someone explain the pea pod to me.
      By domromer in forum General Hammock Talk
      Replies: 28
      Last Post: 11-29-2009, 11:41

    Tags for this Thread

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •