You're better off making your own hi-tech tarp, from 65g/m2 nylon, silicone elastomer coated on both sides. Dimensions should be no less than 280cm x 180cm, with at least 12 loop attachment points, reinforced with cordura. 8 of these loops should be around the outside, and the other 4 through the middle. It's very difficult to find a tarp of this quality, and expensive too. The only people I know of who make a tarp like this is the SASS, Special Air Sea Services. The one they have also accommodates 2 aluminium looped poles, so it doubles as a tent if need be. This is what it looks like:<br>http://www.sass-kit.fsbusiness.co.uk/catalogue16/images/Foul_Weather/hootchie-double.gif<br>