Cooling the boat
Before I try my solar chimney idea, I will try something else I noticed years ago when I carried a hard dinghy over our forward hatch. Without the dinghy over the hatch, the v-berth would be too hot to use at all but with the dinghy making a large enclosed area over the hatch open at the lower edges, somehow it produced a huge amount of airflow through the v-berth with any forward motion.
So, I'll probably try making a tent like thing to fit over the forward hatch with a lot of open area ta the bottom. Should be easy, use some 3/16 fiberglass poles from McMaster Carr and make the tent thing from Tyvek. Fasten it to the toe rails.