Using system dynamics to simulate the management of operation and maintenance of ship machinery under a port availability constraint

The total cost of ship machinery operation (C_T) must be kept at a minimum value while respecting the need for failure. This paper proposes a model to minimize the C_T by endeavouring the value of minimum Reliability Index (RI) of the machinery. The minimum RI is the level of reliability of machinery where we need to take maintenance action after some period of operation time. The changes of minimum RI causes the changes in the composition of C_T, including running cost (C_r), maintenance cost (C_m) and downtime cost (C_d). This paper discusses the operation of pumps which are installed in the cooling system of a ship's main engine. As constraint, the maintenance of the pumps is assumed to be only possible in one particular available port. This study utilizes System Dynamics (SD) to construct two kinds of proposed models of machinery operation. They are model 1, without forecasting and model 2, with forecasting of minimum RI. Model 1 results in minimum C_T, while model 2 reaches a C_T lower than the outcome of model 1.