Wind, First hang, and Turtle dog stands

**SmilinJoe** · 04-27-2014, 20:55

What a weekend! I have really enjoyed visiting and learning from all of you here and also on the BushcraftUSA forum. My son and I have built 2 turtle dog stands and got to do our first hang out at Jacob's Creek Park this weekend.
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It was CRAZY windy! This was my first time setting up the stands together and in the wind and with my tarp. I foolishly got it setup this way and ancored it down with about 15 stakes, guylines on the tarp and on the stand legs. One of the lines slipped off the leg as the wind lifted it off the ground and the whole thing came down and twisted both my gate hinges so my son and I had to set up on the poles of the awning over the picnic table, no pics of that sorry I was brooding. We got to sleep one night in the stands and it was great! I will fix my stands and refine my technique. This was also my first DIY tarp and it held wonderfully in this crazy wind. I would appreciate any pointers on setting up in the wind and advice on a better tarp to use in the wind as well. This was just a rectangular 10x12 BTW. We slept warmly in our MSS sleep systems and had the goretex bivy sack to protect from wind and moisture and our wool blankets. I know the tarp setup isn't as sexy as some i've seen but I was improvising. Anyhow, I really enjoyed our first hang in the wild, we have slept in the backyard a couple of times so I could tune our system. So much fun, my son often just wants to hang after school while he is relaxing before bed time. I find I instantly relax as soon as my feet come of the ground. Glad I found you all and look forward to more hanging.
Joe

**sliver** · 04-27-2014, 21:43

Here's how you calculate the force of the wind on your tarp:

Let's say the wind is 25mph and you have your 10x12ft tarp rigged so that the wind only "sees" 4ft of the 5ft (half of 10ft) because the sides are slanted out.
psf=pounds per sq ft

(25mph**2) * .00256 = 1.6psf (sideways force exerted on your tarp)

12ft * 4ft = 48sf of tarp exposed to the wind.

1.6lbs/sqft * 48sqft = 77lbs

So at 25mph, your tarp has 77 lbs of horizontal pressure trying to knock it over. What gets interesting is that the force on your tarp is directly proportional to the square of the velocity of the wind. That means it only takes another 10mph of wind to double the amount of force on your tarp:

35mph = 3.1psf -> 150lbs (double!)

45mph = 5.2psf -> 249lbs (triple!)

Once you get above 35mph of wind your tarp is getting a lot of pressure. Here are some possible solutions:
o Use more (or wider) stakes. That will help as long as your tarp attachment points can take that amount of force.
o Reduce the amount of surface area you're exposing to the wind. That can be done by finding a spot where the wind is blocked (lee side of bushes and/or trees) OR lowering your tarp closer to the ground by flattening it out.
o Use a hammock sock instead of a tarp. This reduces the surface area you're exposing to the wind by quite a bit, however, it costs more.

HTH

**SmilinJoe** · 04-27-2014, 22:52

Thanks sliver that was incredibly helpful and interesting. It sure looked like a lot of pressure to me. I am glad to hear that my setup could stand that much wind. I would guess we had gusts up to and over 30mph. I will look into a DIY sock.
Joe

**ScottyDale** · 04-28-2014, 13:27

Springtime in Texas! I'm putting together my TDS parts currently, and our mighty breezes are definitely a factor in how I'll plan to go forward. Fine line between hanging and kite flying this time of year!