Rederi Ab Vikinglinjen (later Rederi Ab Solstad and merged into Rederi Ab Sally in 1970) was founded in 1959 and started ferry operations between Gräddö (Sweden) and Korppoo (Finland). The ship used was a ro-ro vessel Viking, which the company acquired in 1959 from a previous owner. The ship was originally known as Dinard before being renamed to Viking.[1] After a disagreement between the founders, a group of men led by Gunnar Eklund left Rederi Ab Vikinglinjen and started a new company, Rederi Ab Ålandsfärjan. The new company purchased the steamer Brittany, renamed her Ålandsfärjan and started operations between Kapellskär (Sweden) and Mariehamn (Åland) in direct competition with Rederi Ab Vikinglinjen.
In 1966, Rederi Ab Ålandsfärjan, Rederi Ab Vikinglinjen and Rederi AB Slite joined forces and founded the marketing company Viking Line in order to compete with Silja Line. During the following years, the three companies ordered many newbuildings and Viking Line became a dominant operator in baltic ferry operations.
In 1970, Rederi Ab Ålandsfärjan changed its name to SF Line, 'S' referring to Sverige (Sweden) and 'F' to Finland. Their first newbuilding was the MS Kapella, delivered in 1967. As a tribute to Gunnar Eklund's wife Ellen, the names of all subsequent new ships of SF Line ends with '-ella'.
When Rederi Ab Sally in 1987 was acquired by Silja Line's owning company EffJohn, SF Line and Rederi AB Slite forced Sally to leave Viking Line. After the bankruptcy of Rederi AB Slite in 1993, SF Line was the only remaining company in Viking Line. SF Line then changed its name to Viking Line.
