As the director of Burmeister & Wain (B&W), Knudsen led the development of the MS Selandia, the biggest, most advanced diesel-powered vessel of its time.

He trained to be a mechanic in Aarhus and worked in this profession until 1882 when he went to Copenhagen to study at the Technical University of Denmark.

[5][7] The ship was received with great interest and many people visited the Selandia including the First Lord of the Admiralty, Winston Churchill, and other high ranking naval officers.

The Fionia was met with similar interest in Germany during Kiel Week, where visitors included German Emperor Wilhelm II and Albert Ballin, director of the Hamburg America Line.

[11] Knudsen resigned from the yard's daily management in April 1919, joining the company's board as an advisor.