Tokyo-based Lepta Shipping has doubled its containership orderbook to $400m by exercising options at Singapore-listed Yangzijiang Shipbuilding.

Lepta, a joint venture between Japanese shipowner Nissen Kaiun and trading house Mitsui & Co, has added five feeder boxship newbuildings at the Chinese shipyard, according to shipbuilding sources.

Containership brokers said Lepta did not order the feeder boxships, which will run on conventional fuels, on speculation.