Can the Florida Marine Patrol impound your boat if you are under the influence?

Yes. It works just like when you get a DUI in the car. The boat gets towed by a tow boat, and impounded, if there's no one sober handy to hand the boat over to. BTW, there's no such thing as Florida Marine Patrol anymore, it's now callled Florida Fish and Wildlife. Same guys, same job, green stripe on the boat instead of black.