I tried hanging from my car this past weekend, wound up sleeping in the car : (
I was in a blow down area and there was only one substantial tree so I thought I could tie the other end to my Yakima roof racks. The rack popped right off of my car and did some damage to the windshield frame. Won't be trying that again!
For posts I use 1 foot wide planks that are about 4-5 foot high each. When you hang the hammock low the center of gravity is only about 1 foot off the ground... so what you have is the same equivalent stability of a 1ft x 1ft x your-hammock-length block that you're laying on... it looks like it should fall over- but it won't.
oh yea - I also weld a large washer on top of the rebar stakes to stop my beaner from sliding off... and they go in at about a 20deg angle leaning away from the post.
It may not be rocket science, but it's still science.
<<Cool sticker! Guess I'm gonna have to order some more biners or something.>>
Me, too...and I even have a Treklight double!!
Most of the Yakima and Thule roof racks clamp on to the car roof via the old exterior rain gutters (early 90's and older cars/trucks/suvs) and on the new cars/trucks/suvs they use an adapter clip to mount to the inside the door to give the feet/towers something to attached to and are basically made to support loads straight down, not out and only about 150 pounds. Very unusuall to find a Yakima or Thule rack system that would screw into the roof. Don't know if they even offer that type anymore. Most aftermarket "factory" style roof racks are made by Perrycraft and they do use 3m double sided tape and small screws to attached to the vehicles roof. I would never trust a roof rack to hang a hammock from. There are some pick up truck ladder racks I would trust to hang a hammock from, but not all of them.
But that set up worked fine. With the tree straps going from the 2x4s down low on the tree, where it is much thicker. Even if I bounced around in the hammock, the trees would not shake or flex at all.
Apparently, signature that I used from 2006 no longer tolerated so now deleted.