One of the neatest tips I have for hot-weather sailing, was something I inadvertently discovered about 5 years ago. I purchased a 7 X 9, heavy-duty, silver tarpaulin from Harbor Freight. The tarps were purchased mainly for winter storage, but I quickly discovered they have another great feature - silver reflects lots of heat. And, that 7 X 9 size was perfect for draping over my Bimini top. I anchored the corners of the tarp with bungee cords, and because the tarp was about 2 to 3 feet larger than the Bimini, it provided lots of side-curtain shad in the afternoon sun. A fellow sailor was on my boat a couple days ago when I had the tarp in place and he was amazed at how much cooler is was in the cockpit than on his boat. Then he reached up and touched the bottom of the Bimini. "Wow! No heat." He purchased a couple tarps the following day.