To add a bit of back story to what I am about to ask advice on. I'm planning a tarp shelter for my up coming trip to Isle Royale National Park. We are planning on backpacking around most of the island in roughly 12 days. What I am looking for is a light tarp for two people. This is my first tent shelter. I have some sewing experience, none on sil or PU nylon. I have read a lot about sewing this stuff and feel like I would be able to manage. I bought an 8X10 blue tarp the other day and have been playing with it. I really like the Half Pyramid Set up.
My idea is to cut off the corners of the half pyramid and use them to fashion a beak attaching a guy line from the beak to the ground. and staking the other edges ether directly to the ground or about 4 inches off for better ventilation. I plan on putting tie outs instead of grommets. What I am asking you for help on is will an 8x10 be big enough to fit two? Where should I place additional guy lines in the main body of the tarp for a tight pitch? Any help would be appreciated. After getting some feedback I plan on cutting into my blue tarp to make a pattern/prototype.
Take a look at this tent I made from some lightweight waterproof ripstop and a package of bug netting. It was made a little high because my wife wanted a little more room inside...and if we were expecting really bad weather we would have added a porch on the front...but it's a great tent. And don't underestimate the value of the bug netting. It's nice to be able to lie in your tent and see the clouds of mosquitos OUTSIDE trying to get in!
I plan on being on the Island for mid August, probably the 16-28th.
I am wanting a simple design that would require minimal sewing and materials. My first thought was to buy a Silnylon tarp from campmor. Set it up in the half pyramid formation cut off the corners to save weight. Then i thought they would be about the right size for a beak to help protect the open side. I realized that I probably didn't want grommets, so I'm thinking pullouts.
I was thinking of using a bug bivy like the six moons design meteor pattern only simplified. Having the netting attach to my ground cloth. I have an old giant Colman family tent i scavenged the no-see-um from. Was thinking of attaching points inside the tarp to tie the bivys to when its needed and take them out when they are not. Or my original thought was to sew netting around the 8x10 before i sew on the beak. I would then add a zipper to one of the sides of the opening.
I'm not sold on ether idea yet. The bivy seems restricting and may tare down the shelter at night if I roll much. The netting would limit some of the pitch angles i could set the tarp at along with being alot more sewing on the large sylnylon.
You might look at the Antigravity 10 foot tarptent for some inspiration. I like mine a great deal.
It is a sort of pyramid with some side pullouts that give a lot more interior room. It has a beak. It also has the option of another piece of fabric that you can use to further button up the front with a fully sheltered vestibule.
One such option is an unusual poncho that can be also used to give a sheltered vestibule to the tarptent.
Loc: Central Texas
I like half pyramids. They are easy to make and endlose a lot of useful space.
8x10 is more than big enough for a half pyramid for 2, especially is you make the long back side with the 10' edge. The 8' width will make for a rather high shelter. You might play with the blue tarp to reduce the body size to about 9x7 or smaller and use the extra to fold under and put the ground sheet on top for a good bug and rain seal. You should have enough scrap on the forward flaps to make a beak. You have probably discovered that changing the height of the peak changes the angle of the back and that you lose a lot of space if the peak is too low. What you may not yet know is that when wet, nylon will sag even more than the blue tarp. So keep the peak as high as you can tolerate it in relation to the width. In other words, keep the angle of the back steep.
One problem with the half pyramid made from a flat tarp is that the stress lines from the peak to the corner stake-outs are along the bias of the fabric so the fabric will tend to deform. You may want to sew some tape along the stress lines - on the inside - so you can seal the stitch line on the outside where it will do some good. The alternative is to piece the pyramid so each long seam joins at least one panel along the weave of the fabric instead of the bias. Obviously, this makes it more complicated, but it makes for a tighter setup.
I made a shelter out of a blue tarp (which doesn't stretch as much as nylon on the bias). It set up nice and taut. When I replicated the shelter in nylon I had an entirely different animal with stretches and sags in new places.