The oceans are big. Think how many floating (or submerged) apartment could exist, each a pressure vessel with links to air, power and heat, fresh water, and a p

The oceans are big. Think how many floating (or submerged) apartment could exist, each a pressure vessel with links to air, power and heat, fresh water, and a personal shuttle to visit other modules. Of course, that's all the same tech that space habitats would use too, so why not do both?