Condition based maintenance optimization of ship hull and propeller
We developed a software module for condition-based optimization of maintenance tasks scheduling for the hull and propeller of large marine vessels.
MESPAS AG provides software for the technical management of ocean-going vessels. In addition to the existing solution portfolio, a new service focusing on condition-based maintenance of the vessel hull and propeller was developed.
The fuel consumption of ships is proportional to their friction resistance in water. The resistance is affected by speed, draft and weather conditions. Another central factor that influences the ship resistance is fouling due to organisms that attach to the hull and propeller and increase the friction with time, leading to an increased fuel consumption over time. This in turn has high costs for the ship operator and harmful effects on the environment.
In order to reduce the fuel costs for the operator, fouling can be removed through one of three maintenance interventions: propeller polishing, hull cleaning, or paint renewal at dry dock. However, these maintenance interventions are costly and are thus performed rather rarely by the ship owners. Moreover, each intervention has a different effectivity, depending also on the fouling condition at that time. The decision when to perform maintenance and which intervention to choose is complex due to the different costs and effects of the various interventions on the future fuel consumption of the vessel.
In the project we developed a model that allows to predict the future fuel consumption of a given vessel based on its historical data. The prediction is then used as an input to an optimization tool that provides an optimal maintenance schedule for a given time horizon in the future, together with an uncertainty estimation of the schedule and the resulting cost saving as compared to the present maintenance policy. This enables the ship operators to take intelligent condition based maintenance decision rather than performing time- and regulations- based maintenance.
The prediction and optimization software is integrated in the Vessel Performance Platform of Mespas AG.