Canadian tonnage provider Seaspan has offloaded a couple of older container ships while adding two more modern vessels.

The shipowner said in a US filing it had sold a panamax unit to Japanese shareholder Ocean Network Express (ONE) in the second quarter, for net proceeds of $17.25m.

Seaspan is continuing to manage the vessel, which brokers said was the 4,253-teu Seaspan New York (built 2005).