Diy 1.1 sil diamond tarp
11' RL 87" wide -slight asym diamond
gross grain bound edges.
1" "cat" cut per short side
1.5" cat cut per long side.
Cat cuts were not true. I just used a batten to put a slight concave to ensure that it was not convex and floppy.
corners reinforced with 2 layers 1.1 calendared walmart ripstop
This past weekend, I was in a thunderstorm. To call it a "deluge" would be like calling the grand canyon "a little crack.". HEAVY rain and 30kt gusts for well over one hour and localized flooding.
I stayed dry under the tarp while my family got wet in my "foul weather" 2 man tent. Rain was splashing up under the tent fly and driving in any gap in the coverage. The only moisture I experienced under the tarp was the "mist" of the rain driving through the sil. more like a fog. Pulling my bug net over me stopped that. I had it pitched at my hammock ridgeline and the sides pulled down pretty tight. I also laid in line with my ridgeline instead of on the diagonal. The wind kept one side of the tarp pushed against me for at least an hour.
I was car camping at a sail club and had several options to get dry, including several friend's RVs and the clubhouse. I fully expected to get wet but wanted to test the tarp when I had a safety net. My concerns were my feet and head are barely covered when in the diagonal and assumed a blowing rain would wet me. It turns out minimal coverage is sufficient.
Overall, I was very pleased with the performance as compared to ease of setup and size. It will be my 3 season tarp in the future. I'm in GA, so my 3 season is warm compared to others. I have a 10x11 sq tarp I use normally. My only dislike is the size and 4 guy outs instead of 2.