Re: Too hot to sail...
Gary, I haven't looked into specs but have been told by multiple sources that even a small air conditioning compressor on a compact car eats five horsepower. Your van? Might easily be 10-12.
Which that's nothing for a car or truck engine to spare (we're talking 100-300hp engines that only need 10hp to cruise on the highway) I don't know many recreational sailboats that could spare 10hp to turn a compressor. or even half of that.
Not impossible, if you have the hp and the space in the engine bay. But at that point, it might be simpler to buy a 15hp engine on a frame, and bolt it all up in a lazarette.
This is why the Vikings didn't go raiding in the hot summer months. :-)