SOUTHWEST HARBOR — The manager of Dysart’s Great Harbor Marina blames a downturn in business on the Maine Revenue Services’ efforts to enforce the use tax on boats. Letters sent to marina customers by Maine Revenue Services (MRS) stating that boat owners might owe a use tax were not well received, according to Micah Peabody, manager. As a result, some of those customers cancelled their plans for tying up at the marina this summer. “We lost some serious revenue,” Peabody said. Maine law requires any boat less than one year old docked in Maine waters for 30 consecutive days or...