Portable Hammock - Pipe Sizing Question

[bwg]

Hi all --

After reading Risk's single pole hammock test (see link below), I decided to use similar configuration to make a portable hammock stand.

http://www.imrisk.com/hammock/singlepolehammock.htm

Today I bought 3/4" galvanized pipe in two 4' sections, attached each to a 2"x4" and was successful in hanging my hammock from both poles. Here are a couple of images to show how I did it.

It worked very well; I weight 200 lbs and have a 40 lb backpack in the hammock. With that combined weight of 240 lbs I rocked in the hammock for several minutes and everything held steady.

While the pipes stayed in placed I noticed that I could move the pipes toward the stakes rather easily which means if one of the pipes were bumped the system could collapse while under load. Given this, I added attached guy lines to the top of each pipe and that made the system much more stable. The result, however, is a mess of lines which can be seen in the images.

I think I will add a set of pipes to form a ridge pole to make the system more stable, like Speer's hammock stand ( http://tinyurl.com/38mu8f4 ; you can see an example of this stand here http://tinyurl.com/38rk8ow ).

Now for my questions. My pipes are 3/4" and they seem plenty strong during my brief test, but after reading several posts I see most on the forum are using either 1" or 1.25" pipe.

1. Will 3/4" pipe be sufficient when I add a top bar along the ridge? The walls on this pipe is .113" while 1" pipe is .133 and 1.25" pipe is .14 thick (EMT conduit is about .065 thick).

2. Which faces greater stress/force, the ridge pole or the upright pole? I ask this because I am considering using my 3/4" pipe as the ridge pole and buying 1" as the upright poles. Will 3/4" be able to handle the load as a ridge pole?

Thanks for any help you can provide.

[nonamesleft47]

I like this. I would think that the ridge pole would take the brunt of the pressure but if the two 3/4" uprights hold you it looks like you would be oK using a 3/4" ridge pole. But then I'm a newby so I'd wait until more experience chimed in...
You could use 2 6-7 foot pieces for your ridge pole and connect them with a sleeve to make it more portable. What did you use to hold your guy lines in place? I'm looking for something like this for backyard use as I have no trees. This looks like you could disassemble it in minutes and it wouldn't take up much space in the garage.

What did you use to hold your guy lines in place?
How much did your supplies run for this?

[bwg]

Hi --

Since I posted above I've decided not to use a ridgepole. I'm going to use guy lines, but fewer of them, so it is cheaper and less bulky for travel. Also, I like using guy lines -- it's a geek thing. If you seek a backyard system, perhaps a cheaper approach is to buy the generic "Vario" stand that can be found here for $99 and free shipping:

http://tinyurl.com/dcxl87

See this forum link for a discussion of the more expensive Vario, and for this copy of it:

http://www.hammockforums.net/forum/s...ighlight=vario

Another option, if you have a local Ag Supply, is this $55 hammock stand:

http://tinyurl.com/38ypksh

If you are interested in guy lines, like me, you can see what I plan to do with my system as shown in the first image display I have attached.

Note that the hammock suspension is independent of the pole support guy lines. If you look closely at the second image in my original post above you can see that my hammock suspension runs through the tee fitting (which I lined with nylon to prevent abrasion on the suspension; one could also use a hose for this purpose). Most folks run the guy lines directly to the poles, then hang their hammock to the poles. This method results in the poles being pulled toward the hammock which also produces tarp sag.

Running the hammock suspension through the tee fitting seems to greatly reduce the inward bend of the poles toward the hammock. The additional guy lines used to stabilize the poles should prevent most any movement as a result of entering the hammock. So this method should allow me to attach a tarp without sag, or with very little sag. I'll be able to report in more detail this weekend once my webbing arrives for the guy lines.

You asked specifically about my guy line anchors. I bought 18" stakes at Lowes ($2.78 each), 12" galvanized nails ($0.80 each), and COL-MET 12" Brown Steel Landscape Edging Stake ($1.07). Links below:

18" steel stake = http://tinyurl.com/2b5g23v
COL-MET 12" Brown Steel Landscape Edging Stake = http://tinyurl.com/28bw9rd

I use these stakes/nails to form a 1-to-1 picket holdfast. First I placed the steel stakes a distance from the pole of twice the pole height (this gives an angle of about ~23 degrees assuming the ground is flat). I leave about 7" or 8" of the stake above ground. Next I drive the landscaping edging stake in front of the steel stake to give it more surface area. Next I attached the hammock suspension, then drive the galvanized nail behind the steel stake about 1.5 feet. I also place a landscaping edging stake in front of the galvanized nail to give it more surface area. Next I take webbing that is about 3 feet long (with loops sewn in) and attach to the nail and to the steel stake. I take a second 12" nail and place it between the webbing then I twist until the webbing is tight between the nail and steel stake, then I drive that second nail into the ground.

The process is displayed in the two images of the holdfast; the second image shows what I do -- big stake, nail through webbing and into ground, second stake to which is attached the webbing.

The strength of this system is remarkable. I live in south Georgia where we have our share of sandy soil. I found a very loose area in my yard and created the picket holdfast as described above. I attached a rope from the steel stake and placed it over our swing set, then I hung from it and bounced a bit. I weigh 200 lbs. Next I wore my backpack with 40 lbs and repeated the hang -- again, it held tight with little evidence of movement. Keep in mind this is just one picket holdfast! To make clear how remarkable this is, you must know that the soil in this spot is so loose that I was able to lift the steel stake (driven ~10" into the ground) with just my thumb and index finger; in fact, I could easily move it up and down. However, even with that looseness, it was able to hold me and my backpack at a combined weight of ~240 lbs.

I am sure using four picket holdfasts, two on each end of the suspension, will prove very adequate in most soil conditions. For camping on sandbanks I plan to take four 2x4 wooden stakes about 24" long to serve as the primary stake and then use the 18" steel stake as the rear support for those 2x4 stakes.

I'll post images of my revised stand later this weekend once my webbing arrives.

[coolkayaker1]

bwg--see most recent posts on the Vario thread you link. The $99 hammock stand is NOT a Vario, it is, as you state, a generic knock off (I know you know this, I just wanted to reiterate it for others). Well described in the link/thread you've given. I just wanted to post here so that your readers won't be confused and will know what they are buying if they decide on Dubose stand (Vario knock off at $99) or the Byer of Maine Vario ($150). The differences are well-documented on the thread linked by bwg, and now mentioned by bwg and by me.

Thanks for interesting photos of your project, bwg. Great and comlpex physics in your project. Fun!