Or a yacht 11 miles past the continental shelf… international waters. But I think the boat is subject to the jurisdiction of the flag it flies. Portugal is a subject of the eu and can’t violate the laws. Try this: Live on a boat docked in Miami with a cayman island flag. Not sure what cayman citizenship costs…. But unless you relinquish US citizenship you are still subject to us code. There may be better places to doc your cayman boat like the Bahamas, Isle of Man, or Guernsey