Some crossings that are longer than 1000 km, as the crow flies (current as of 2012):

* [Travemünde–Helsinki](http://www.eurail.com/trains-europe/ferries/finnlines): 1095 km
* [Cadiz–La Palma](http://www.trasmediterranea.es): 1382 km
* [Hirsthals–Seyðisfjörður](http://www.smyrilline.com/info/Arrival_-_Departure.aspx): 1504 km
* [Alaska Marine Highway](http://www.dot.state.ak.us/amhs/schedule_pdf.shtml) has some long routes: Selgovia–Dutch Harbor (1096 km), Bellingham–Skagway (1451 km). But nothing beats [Bellingham–Homer](http://www.dot.state.ak.us/amhs/doc/schedules/Summer12/CrossGulf_S12.pdf) with **2219 km**. Question is if this is still a ferry considering it doesn't go very often (apparently just three times a year).
* Norwegian Hurtigruten takes cars: [Bergen–Kirkenes](http://www.hurtigruten.com/) which is 1541 km as the crow flies, but at least twice as long with the route it actually takes.