There are these contraptions that condense water from the air, though they are very slow since there's generally not that much humidity, and the contraptions don't have much temperature gradient available to condense with.

But suppose you're near the ocean, maybe even on a boat. Won't there be tons of water vapor near the ocean surface from sunlight hitting the water? And you've got lots of cool temperature available a few feet below the surface.

So would it be practical to collect fresh water by lowering some kind of condensing apparatus into the water, and using it to condense water from the air above the ocean? Could this be more efficient than reverse osmosis?