Irish Continental Group (ICG) has bought its sixth containership.

The Dublin-based shipowner, best known as a ferry operator, said it has acquired the 974-teu CT Rotterdam (built 2009) for an undisclosed price.

In a statement Wednesday, ICG said it had invested more than €25m ($22.7m) in expanding and improving its container fleet in the first ten months of the year.

That included the purchase of in April of the 1,421-teu Thetis D (built 2009), a deposit on the acquisition of the CT Rotterdam, and initial investment in exhaust scrubber systems for its vessels.

Alphaliner lists the CT Rotterdam as the fourth ship in the ICG fleet of the RW 850 design, of which a total of 19 vessels were built from 2006 to 2009 by Germany's Hegemann Group.