MS Estonia was a car-passenger ferry built in 1980 for the Finnish shipping company Rederi Ab Sally by Meyer Werft, in Papenburg, West Germany. She was deployed on ferry routes between Finland and Sweden by various companies (first Viking Line, then EffJohn) until the end of January 1993, when she was sold to Nordström & Thulin for use on Estline's Tallinn–Stockholm route. The ship's sinking on 28 September 1994, in the Baltic Sea between Sweden, Finland and Estonia, was one of the worst peacetime maritime disasters of the 20th century, claiming 852 lives. An official inquiry found that failure of the locks on the bow visor caused water to flood the car deck and quickly capsize the ship. The report also noted a lack of crew action. A 2023 investigation noted additional construction flaws in the bow visor.

Construction

The ship was originally ordered from the Meyer Werft shipyard in Papenburg, Germany, by a Norwegian shipping company led by Parley Augustsen with intended traffic between Norway and Germany. At the last moment, the company withdrew their order and the contract went to Rederi Ab Sally, one of the partners in the Viking Line consortium (SF Line, another partner in Viking Line, had also been interested in the ship).

Originally the ship was conceived as a sister ship to Diana II, built in 1979 by the same shipyard for Rederi AB Slite, the third partner in Viking Line. When Sally took over the construction contract, the ship was lengthened from the original length of approximately 137 metres (449 ft) to approximately 155 metres (509 ft) and the superstructure of the ship was largely redesigned.