Hyundai said the ships, which are used to find oil and gas, would be delivered to Rowan Companies by the second half of 2013.

The contract includes an option to order an additional ship in the same class, the company said, adding it brought Hyundai's total drill ship orders this year to $5.0 billion with options to build three more.

Hyundai has secured orders valued at $11.7 billion to build 44 ships so far this year, achieving 60 percent of its yearly target of $19.8 billion.

Copyright AFP (Agence France-Presse), 2011