Boat rentals along ICW in Ft. Lauderdale area

My husband and I are planning to rent a small powerboat in the Ft. Lauderdale area and head to Key West along the intracoastal waterway, stopping at marinas/hotels along the way, so boat size is not for sleeping but merely transportation. Any suggestions of where to rent a boat?

pretty sure no one will allow a small powerboat to go that far from their base. Great fun idea, but I don't expect any options unless you toss in a lot more $$$$