Submersible accomodation isn't actually that hard or expensive: You don't have to go very deep to reduce wave action to next to nothing, only 10-20 meters, and

Submersible accomodation isn't actually that hard or expensive: You don't have to go very deep to reduce wave action to next to nothing, only 10-20 meters, and you only need to submerge in heavy weather. There's one guy on the forums who built a couple of concrete teardrop hulls and used them as yachts. He said they were pretty comfortable.