Waterworld
The basics:
MARITIME ZONES AND BOUNDARIES
"Each coastal State may claim a territorial sea that extends seaward up to 12 nautical miles (nm) from its baselines. The coastal State exercises sovereignty over its territorial sea, the air space above it, and the seabed and subsoil beneath it. Foreign flag ships enjoy the right of innocent passage while transiting the territorial sea....
Each coastal State may claim a contiguous zone adjacent to and beyond its territorial sea that extends seaward up to 24 nm from its baselines. In its contiguous zone, a coastal State may exercise the control necessary to prevent the infringement of its customs, fiscal, immigration or sanitary laws and regulations within its territory or territorial sea, and punish infringement of those laws and regulations committed within its territory or territorial sea.
In 1999, eleven years after President Reagan extended the U.S. territorial sea to 12 miles, President Clinton proclaimed contiguous zone extending from 12 to 24 nm offshore.
Each coastal State may claim an Exclusive Economic Zone (EEZ) beyond and adjacent to its territorial sea that extends seaward up to 200 nm from its baselines... Within its EEZ, a coastal State has: (a) sovereign rights for the purpose of exploring, exploiting, conserving and managing natural resources, whether living or nonliving, of the seabed and subsoil and the superjacent waters and with regard to other activities for the economic exploitation and exploration of the zone, such as the production of energy from the water, currents and winds; (b) jurisdiction as provided for in international law with regard to the establishment and use of artificial islands, installations, and structures, marine scientific research, and the protection and preservation of the marine environment, and (c) other rights and duties provided for under international law.
The U.S. claimed a 200 nm EEZ in 1983 (Presidential Proclamation No. 5030 of March 10, 1983..."
http://www.gc.noaa.gov/gcil_maritime.html
Come hell or high water, your floating Utopia needs to remail on station or anchored at least 25 nm out and quite probably more than 200 nm out
That makes it a very risky and very expensive proposition.