Azipods are becoming popular on ferries, especially with hybrid and diesel/electric propulsion:
A new ferry for Wasaline is nearing completion in Finland.
Umeå is 400 km south of the Arctic Circle, so hardly the “northernmost all-year passenger ferry route” by any stretch of the imagination.
Hurtigruten operate year around “ferry service” were half the route is north of the Arctic Circle and has done so for over 125 years.
OK, not the same kind of “ferry service”, but there are many car/pax ferry services in Norway north of Trondheim.