Norwegian shipbuilding group Kleven Maritime AS won a $477m contract to build six ships
for Siem Offshore, the companies announced.
Kleven said the contract shared by its two western Norway yards was the largest in its history.
The shipyards will deliver six, 292-ft. anchor handling tugboats during 2009 and 2010, with an option for six more in 2010.
The ships will be capable of anchor handling as well as construction work for the offshore oil industry.