Strategies for Improving Ship Overhaul Project Planning

This paper proposes a linear mixed model RCCP (Rough Cut Capacity Planning) to plan ship overhaul projects characterized by a sparse precedence graph. RCCP models are typically designed for the early phases of projects and aim at deciding the work package’s execution intensities for each project planning period. This work is interested first in the minimization of the makespan (Resource-driven). Improvements in the model resolution are proposed to speed up the MIP solver to solve the model. These improvements are based on observations from a detailed analysis of the behavior of the MIP solver and the analysis of the structure of the feasible solutions. Then, the impact of the changes made according to the observation drawn from the makespan minimization is taken into account to propose a strategy to improve the basic model in the case of minimizing the costs of using external resources by setting the project’s end date (Time-driven). The effectiveness of the proposed strategies are tested on a benchmark of 90 instances. Our results demonstrate that the proposed strategies allow us to quickly solve the ship overhaul tactical project planning problem to optimality for all tested instances