Development of a mathematical model for ship repair time estimation

Abstract

Docking of ships for maintenance and repair are highly sophisticated works and simultaneously it is labour intensive with strict time constraints. Fundamentally, ship repair time indicates the duration of stay of a ship in a dockyard for maintenance services. The importance of ship repair and maintenance in Bangladesh have been explained as well as the scope of present research work has been discussed with specific objectives and outcomes. Later the significance of ship repair industires have been established and literature review has been conducted to find the condition of research and development of this sector. There are very few publications in the discipline of ship repairing procedure and estimation of repair time. Therefore, further research and development are quite necessary in this field. Hence one of the main objectives of this study is to document the ship repairing procedure from beginning to end. In this point of view the complete ship repair procedure from docking to undocking of a vessel has been described. There are various types of repair works like hull cleaning, sandblasting, painting, steelworks, valve repair, piping, mechanical works, electrical, and miscellaneous works. After that a comprehensive study has been performed to explain the theoretical background and related statistical parameters to construct a mathematical model. Later, this thesis discusses the development of mathematical model of ship repair time in detail. Repairing time and related information like principal dimensions, scope of repair works for different ships were collected. A multiple linear regression model has been developed and analysed. In this particular model, ship repairing time is the function of ship’s gross tonnage and different repairing works of mainly sandblasting, valve repair, hull cleaning, hull painting, structural steel works, and tank cleaning works. Theory of least square has been applied to evaluate the regression coefficients. Several case studies have been performed to evaluate the performance of the mathematical model. To carry out the case studies a different set of data have been used. So far the results have been satisfactory. Finally, some recommendations have been proposed to do further research in this field. This study will be helpful for the industrial personel as well as academic student to get a clear idea of ship repair procedure from beginning to end and it is believed that this model may support the management to estimate repairing time for providing better service.