Shanghai-listed Jinjiang Shipping has firmed up options for four more 1,900 teu containerships at Yangzijiang Shipbuilding, doubling its latest feeder newbuilding programme. The Shanghai International Port Group-controlled carrier said its wholly owned subsidiary Manqiang Shipping has signed contracts with Jiangsu New Yangzi Shipbuilding and Jiangsu Yangzi Hongyuan Shipbuilding for the additional quartet. The contracts are …