Marine AC using fresh instead of raw water?

[aybabtme]

I'm interested in installing a AC unit on our boat to control humidity when away, and to cool/warm the cabins every now and then. But I don't want to add a thru-hull for it if I can avoid it: I don't have a haul-out scheduled soon and would rather avoid the hole. At the same time, our water heater is defective and needs to be replaced. So I got thinking.

Could I plumb a loop in the hot water line, before the water heater, that would go through the AC unit instead of the raw water? I'd pre-warm the water headed for the water heater, and avoid all the complications of the raw water intake going in the AC unit. When no one is showering, the AC unit would loop the water until it gets progressively warmer (and my guess is it won't ever get so warm that the AC won't be able to work anymore). When someone uses hot water, the AC would be getting cold water from the tank, so no issues there.

Has anyone done this?