Its 5,000-dwt Siem Stingray has been hired by Subsea 7 for an initial three years, with an option for two more.
The ship will fill a contract which Subsea 7, which is also owned by Norwegian magnate Kristian Siem, secured from BP last week.
While Siem does not say how much the charter is worth, Arctic Securities analyst Kristoffer Riis Iden estimates it to be in the region of $55,000 per day.
He explains the charter is a positive development for the owner given market concerns the level of subsea newbuilding orders seen in recent times.
Oslo-listed Siem carded a profit of $17.8m in the first three months of 2014, down marginally on the $18.8m of a year ago.
EBITDA of $36.9m was fractionally below of the $38m consensus, with Iden noting the miss was due to the performance of its non-core Brazilian supply and oil spill recovery vessels.
Its anchor handlers performed well, with the 70% margin on its subsea vessels impressive, the analyst says.