Greek owner Nikolas D Pateras is continuing his slow but single-minded expansion in the feeder containership market, striking deals to buy six more vessels.

In one of two deals, Athens-based shipowning sources said Pateras’ Contships Management Inc is behind a $24m deal for four boxships previously owned by Germany’s Hartmann Schiffahrts.

They are the 1,114-teu sisterships Frisia Aller, Frisia Iller and Frisia Alster (all built 2007), and the Frisia Inn (built 2008).