Planning Mass Production of Merchant Ships in Japan during the Pacific War

Building merchant ships was one of Japan’s top priorities during the Pacific War because marine shipping capacity was a decisive factor in the outcome of the war. The Planned Shipbuilding scheme carried out by the Technical Department of the Navy was a scheme to achieve a drastic increase in merchant shipbuilding. The Technical Department of the Navy designed the Wartime Standard Vessels and assigned one or two types of such vessels to each private shipyard, and managed the progress of each ship using the Bar Chart system. Under this scheme, merchant shipbuilding did indeed soar, and the productivity of shipbuilding substantially increased. In this article, I showed that Nagasaki Shipyard of Mitsubishi Heavy Industries Co., which specialized in building Wartime Standard tankers along with naval ships, achieved a sharp increase in labor productivity from FY 1942, even under conditions of a declining capital–labor ratio and declining labor quality. At the same time, the shipbuilding period was reduced to less than half what it had previously been. This increase in productivity and the reduction of the building period reflected various ingenuities introduced at the shop-floor level in customizing the design of the Wartime Standard Vessels, improving operations, and introducing two basic technological innovations, block building and electric welding.