Most ship management companies base the operational cost calculation on scheduled maintenance jobs. Scheduled maintenance jobs do not take unforeseen maintenance into account. This under-estimates the operational budget. The estimation of the operational costs can be improved by including the unforeseen maintenance costs. The amount of unforeseen maintenance costs depends on the implemented maintenance policy, as well as the failure and maintenance intervals. To study this inter-action a model is required. A Maintenance Cost Model (MCM) is developed and validated to demon-strate the impact of maintenance policies at Anthony Veder. This model focuses on maintenance cost calculations for different maintenance policies, based on failure behaviour. Anthony Veder will be able to save 60% on average on maintenance costs of mechanical equipment by optimising their main-tenance policies. Although applied to Anthony Veder the developed model is generally applicable offering ship management companies’ insight in suitable maintenance options.