The downturn in global shipbuilding that started in March has accelerated. Exports of completed vessels from China, Japan and South Korea fell 31% on a year earlier in September, led by a 55% slump in shipment from South Korea. As a result the past 12 months total has fallen to $4.6 billion, the lowest since at least 2009. There’s little prospect of a near-term turnaround given Chinese export orders in September were their lowest since October 2016, when Hanjin Shipping went into bankruptcy. Container-liner orders are unlikely to accelerate in the near-term given profits are still recove...