I will again note all the bitching about how complex the regs are, or have been. Simple is "closed" because something almost always needs protection. I think they certainly could have done better because they can regulate for time, place, and manner.

Boats with no more than two people, no closer than X feet while not fishing from a boat. It could be done, but it would be complex.

I think on some of the Cruise Ships they found virus lived up to 17 days.