Integration of long-term planning and mid-term scheduling of shipbuilding

Abstract

A shipyard’s production plan has a hierarchical structure comprising a long-term plan and a mid-term or short-term plan. The mid-term schedule is established based on the major schedules of the long-term plan. However, in the long-term planning stage, the mid-term schedule is not considered owing to timing discrepancies and the lack of data. Therefore, even if a major schedule is changed to achieve production goals – such as workload balancing in the mid-term scheduling process – this is not reflected in the long-term plan. To solve these discrepancy challenges in conventional production planning, the problems of an existing shipbuilding production planning process were derived, and an algorithm to optimize the berth schedule by reflecting the mid-term schedule when establishing a long-term plan was developed. The developed methodology and algorithm were installed in an existing planning system and applied to an actual shipyard production planning process. Results showed improvements in long-term and mid-term scheduling.