Size of a solo tarp

Posted by: Jim M

Size of a solo tarp - 10/11/18 10:52 PM

I have considered making a DIY ultra-light tarp. It would be for solo use and mostly A-frame configuration. I have a 9' x 9' (3m x 3m) tarp and it is way too big for solo so it weighs more than need be. I have an 8 x 10 foot nylon tarp, but that is an odd size. So to protect from rain, what size can I get by with? I probably would not have a bivy bag unless I was up high or in snow.
Posted by: Glenn Roberts

Re: Size of a solo tarp - 10/12/18 12:16 AM

I usually used a 6’x8’ tarp for solo trips, and found it adequate. An 8’x8’ always seemed ideal, with the square shape offering some additional pitches (but since I could never find one, maybe not?) I usually used a 3’x7’ groundcloth with it.

I usually swapped the ground cloth for a bivy if I knew I’d be in heavy rain.
Posted by: Bill Kennedy

Re: Size of a solo tarp - 10/12/18 04:10 AM

In Beyond Backpacking,Ray Jardine suggests 86" wide and for length, adding 36" to your height, for a 1-person tarp.

I made a 2-person Ray-Way style tarp using the instructions in Beyong Backpackingand The Ray-Way Tarp Book. I made the net-tent, too, although I modified it somewhat, making it a little wider and adding a curved zipper door. I used 2oz. taffeta for the floor. I also used a different method of attaching the side pull-outs on the tarp, which I think worked better.

It's worked well. A bit tricky for one person to set up in a stiff wind, but doable. The "variable geometry" beaks work, too. The lower you pitch it, the more the beak angle lowers, so it's possible to pitch one end very low, all the way to the ground, and the other end higher. I did this one night when it was windy and I couldn't get it set up the "regular" way. The net-tent doesn't work well that way, but if it's that windy, mosquitoes shouldn't be a problem.

My 2-person tarp is 1.3oz. silnylon, 106"x106" and weighs 18oz. with all the guylines attached, including for the side pullouts, but without stakes. It takes 12 stakes to guy out all points, and I've usually carried 2 MSR groundhog and 10 titanium. An additional 4 stakes are needed to stake down the net-tent if desired, but it's not necessary.

Ray's kit might be worth investigating. I'm not sure whether the book is included or not.
Posted by: Jim M

Re: Size of a solo tarp Conclusions - 10/12/18 01:47 PM

Thanks for your very interesting comments. Length: I thought Jardine's formula was reasonable. For me that is 68' + 36" = 104'. It may suggest more length than is needed for mild conditions, but for an extra 8" (experience tells me 96 inches as a minimum) is well worth the weight. As for width: Jardine's 86 inch recommendation (7.17 feet) seems reasonable. Pitched with a 90 degree peak that would make the triangle looking at the front of the "tent" 43" on two sides and a whole 60" across the bottom (if I remember my Pythagorean theorem correctly and my math didn't falter). So my conclusion is 104" x 86" and that is 7.17' x 8.67' would make a very nice solo A-Frame configuration. Interestingly enough that area (62.2 SF) is roughly the same as the 8' x 8' tarp (64 SF). The only advantage I might see in the 8x8 square is that it would set up nicely as a flying wedge. So perhaps 8x8 would win on flexibility, but the 7.17 x 8.67 would be better in the A-frame set up in a storm.
Posted by: Bill Kennedy

Re: Size of a solo tarp Conclusions - 10/12/18 03:33 PM

If you haven't already, check out Ray's site. There are lots of good pictures of his tarp set up different ways. There's also an interesting video of a cuben fiber tear test, which seems to put the lie to the idea that it's stronger than silnylon.

The "variable geometry" idea regarding the beaks confused me at first. In fact, I didn't really get it until I'd made the tarp and set it up. The beak actually becomes a vertical wall if pitched very low and wide.

The square tarp with no beaks could probably be set up more different ways, but it seems like you'd want it a little bigger.
I've only used a square tarp once, and it was 10'x10' and big enough for two people.
Posted by: Pika

Re: Size of a solo tarp - 10/12/18 05:08 PM

I’ve used the RayWay single-person tarp, a silicon nylon backpacker poncho I got from Campmoor and a GI poncho through the years. The GI poncho could be configured into an adequate, cramped and heavy shelter, I don’t have its dimensions though I’m sure you can find them on line. The backpackers poncho (about 5’ by 8’) was a totally inadequate shelter and the RayWay tarp was/is great.

I sat out two powerful Arizona summer thunderstorms in the RayWay and endured a day and a half of rain and wind on one occasion in the northern Picket Range of Washington under it. I stayed dry and suffered no condensation at any time. I have mine fitted with loops that will suspend a Six Moons Serenity Net Tent for mosquito protection. If I have to pitch the tarp low the net tent isn’t all that comfy though.

A flat silicone nylon tarp the size of the GI poncho may be a bit lighter than the RayWay tarp but, for me, the extra room of the later would be worth a few extra ounces.

Also, I recommend Jardine’s “Tarp Book” as a resource.