Oslo-listed Siem revealed Sorensen was stepping down today with Idar Hillersoy named as his successor.

Svein Erik Mykland will also be replaced as chief operating officer, although he will remain with the company and take over responsibility for the follow up and development of Siem Offshore Contractors.

Calls to Eystein Eriksrud, Siem’s chairman, seeking comment were not answered on Friday afternoon. It was also not possible to reach representatives at the company’s head office.

Hillersoy’s promotion comes just a few months after he was made chief executive of the newly formed OSV division as part of a streamlining in April.

Sorensen has been chief executive of Siem Offshore since 2005 and spent the previous four years as chief financial officer.

Hillersoy has more of an operational background, having led Secunda Canada, in which Siem has a 50% stake, been chief operating officer at Simon Mokster Shipping and also worked at Seabrokers.