Gallery Video Directory Hammock Articles Donate Hammock Forums Store Today's Posts Mark Forums Read
 Hammock Forums - Elevate Your Perspective Ridgeline Physics
 Home Forums Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

 07-08-2007, 09:30 #1 Curt Senior Member     Join Date: Apr 2007 Location: Pacific Northwest Posts: 193 Ridgeline Physics Good morning! I'm trying to figure out the physics of the different loads that hammocks create. One of the things I'm scratching my head about is the ridgeline vs. the tree connection. It seems pretty common to not go less than 900+ lbs on the tree suspension straps. Most around here go 1200+ based on posts I've read. But the structural ridgeline numbers are MUCH lower - some folks using as little as 200 lbs. Is it really under that much less stress?? Anybody have the math on this so I can play with some numbers? On another note, what kind of rating would be needed on a combined structural ridgeline/tree connection line? I'm talking about a straight line between two trees, likely under a lot of horizontal tension to get it tight, then hanging the hammock from that - pretty much a clothesline setup. Thanks much! I'm having fun tinkering with different setups and wouldn't be having the great time I am without all the fantastic input of folks in this forum! -Curt
 07-08-2007, 09:58 #2 blackbishop351 Senior Member     Join Date: Oct 2006 Location: Greensboro, NC Hammock: Homemade Speer-type Tarp: BlackCat Insulation: Potomac UQ View my gallery 59 Posts: 1,566 Images: 59 There have been a couple threads in which the suspension and ridgeline tensions have been worked out. Yes, with "commonly used" sag angles, the ridgeline is under much less tension than the suspension. Using a continuous rigeline/suspension wouldn't change the way the forces are distributed, but because the material used would have to take the higher suspension forces along its entire length, you might well end up with more weight than you need that way. __________________ "Physics is the only true science. All else is stamp collecting." - J. J. Thompson
 07-08-2007, 12:38 #3 warbonnetguy   Join Date: May 2007 Location: fort collins, co View my gallery 47 Posts: 3,997 Images: 47 try this experiment, have someone else lay in your hammock to weight it, attach one rope to each suspension point, where the suspension rope attaches to the fabric, like you would attach a external ridgeline over the netting, now pull them together so they meet in the middle of the hammock above the netting. cross your arms and pull, i was able to pull the ends several inches closer together this way just by hand, in a sense you are just making the hammock "taco" a bit from end to end. it doesn't take nearly as much force as you might think. here is what determines how much. the ridgeline will always be horizontal, it is the suspension lines that will vary. if the suspension lines were hanging straight down, the ridgeline would be directly perpendicular to the suspension lines and thus the less force needed to pull the ends closer together.in contrast, if the suspension lines are cranked down so they are almost completly horizontal to the ground, the ridgeline is no longer pulling anywhere close to perpendicular to the suspension line, and more force is needed to pull them in this direction.in reality, this worse case scenario seems to be hard to create, because even if the suspension lines are horizontal to the ground during setup, once weighted, they will not stay that way, and will be angled down toward the ground, so that the ridgeline is at least partially perpendicular to them, another thing i just realized 2 seconds ago.(so i may be wrong) it seems like the longer the suspension lines,the less force needed to pull the ends a fixed amount closer together, the shorter they are, the more force needed, maybe one of the math guys knows if this is true or not. hope this helps, i know all the equations on these subjects can be hard to follow, i think tangents and cosines is where i gave up on math, and i don't even try to understand the mathematical statistics side of it anymore, just makes me more confused. lol. hope this helps...Brandon
07-08-2007, 14:24   #4

Join Date: Apr 2007
Location: Illinois
Hammock: DIY Bridge, v0.n, where n is large
Tarp: depends on season
Insulation: DIY UQ
View my gallery 564
Posts: 4,684
Images: 564
Quote:
 Originally Posted by Curt Good morning! I'm trying to figure out the physics of the different loads that hammocks create. One of the things I'm scratching my head about is the ridgeline vs. the tree connection. It seems pretty common to not go less than 900+ lbs on the tree suspension straps. Most around here go 1200+ based on posts I've read. But the structural ridgeline numbers are MUCH lower - some folks using as little as 200 lbs. Is it really under that much less stress?? Anybody have the math on this so I can play with some numbers? On another note, what kind of rating would be needed on a combined structural ridgeline/tree connection line? I'm talking about a straight line between two trees, likely under a lot of horizontal tension to get it tight, then hanging the hammock from that - pretty much a clothesline setup. Thanks much! I'm having fun tinkering with different setups and wouldn't be having the great time I am without all the fantastic input of folks in this forum! -Curt
TeeDee gave the definitively analysis here. You got an equation, plug and chug those numbers to your heart's content.

I later chimed in with an anal retentive explanation of the formula, because I didn't understand where it had come from. TeeDee has a more intuitive approach to about this stuff than I do.

Grizz

 Bookmarks

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Site Topics     Introduce Yourself     Announcements     Feedback and suggestions     Articles Hammock Camping     General Hammock Talk         Long distance travel with a hammock     Suspension Systems, Ridgelines, & Bug Nets     Top Insulation     Bottom Insulation         Pads         Under Quilts     Weather Protection     Do-It-Yourself (DIY)         Fabrics         DIY Stickies Outings     Hangouts, Campouts, and Trip Planning         Northeast         Southeast         Midwest         Southwest         West         All Others     Trip Reports Marketplace     For Sale         Group Buys         Pay it Forward         [SOLD] items no longer available     For Trade         [TRADED] Items no longer available     Want to Buy Hammock Gear - Manufacturers and Services     Reviews     Other Vendors and Services     Arrowhead Equipment (Home of Kick Ass Quilts)     Butt in a Sling Hammock Gear     Clark Jungle Hammocks     Claytor Hammocks     DD Hammocks     Dream Hammock     Dutchware     Eagles Nest Hammocks     Grand Trunk     Hammock Gear     Hennessy Hammocks     2QZQ Hammock Specialties (Hennessy Bugnet Zipper Mods)     Jacks-R-Better     Molly Mac Gear     OES Tarps     Tree to Tree Trail Gear         Speer Hammocks     Trek Light Gear     UGQ Outdoor Equipment     Warbonnet Hammocks     Whoopie Slings     Wilderness Logics

All times are GMT -5. The time now is 09:22.