Planned Shipbuilding and Nagasaki Shipyard of Mitsubishi Heavy Industries Co. during the Pacific War

Because the consequence of the Pacific War hinged on the marine shipping capacity of Japan, the Japanese government and the military gave top priority to merchant shipbuilding. Planned Shipbuilding, of which the Technical Department of the Navy from 1942 took charge, was a scheme designed to achieve mass-production of merchant ships. The Technical Department of the Navy planned the monthlyprogress of each merchant ship for each private shipyard using bar charts. Huge volume of materials and labor force was mobilized for Planned Shipbuilding, and merchant shipbuilding increased sharply until 1944 FY. It is notable that the increase in the output was substantially larger than that in the input. That is, a large part of the increase in merchant shipbuilding can be attributed to the productivity increase. This paper reveals that using the data on Nagasaki Shipyard of Mitsubishi Heavy Industries Co. During the war, Nagasaki Shipyard was specialized in building wartime standard tankers besides naval ships, and achieved sharp increase in labor productivity, while the capital-labor ratio declined, and the quality of labor force deteriorated. In addition, the average days for building a merchant ship was reduced to less than half. This increase in productivity reflected various ingenuities in the design and the production process of ships, based on the two basic innovations, the block building and the electric welding.