You didn't say what your attorney's opinion was. You do have one.
My attorney doesn't see what the big deal is. She acknowledges it's not a common life choice but also understands it's a boat in a marina, not the space station. The key is to present enough information to the court to allow them to rule on an issue that they have no personal experience with. Anecdotes relating to kids on boats would go a long way in doing that.