The company said it has signed contracts for two firm 63,800-dwt ships, with an option for a third.
Last year, Atlantska signed up at the yard for three 38,000-dwt handysizes, with an option for another.
It said on Wednesday that the new firm ships replace the final two handysizes in this series.
The move was prompted by rising demand for ultramaxes, it added.
It has three months to declare the option. No price or delivery details were given.
