In 1977 Olau attempted to start a service from Sheerness to Dunkirk, France, but this was not successful. By the end of the 1970s the company was in heavy debt, and in 1979 Ole Lauritzen was forced to sell 50% of Olau Line to the West Germany-based TT-Line. The following year Lauritzen sold his remaining shares of the company to TT-Line.
Olau Line's endeavor to establish a service from Sheerness to Dunkirk, France in 1977 failed. By the end of the decade, the company was heavily insolvent and by 1979, Ole Lauritzen was forced to cede control of Olau Line to TT-Line, a German shipping firm. The following year, Lauritzen sold his remaining stake in the company.