Advanced operational measure for reducing fuel consumption onboard ships.

Environmental issues and targets to reduce greenhouse gas emissions have reinforced attempts to increase energy efficiency for all stakeholders, including the shipping industry. International maritime organization (IMO) has prescribed operational and design measures to develop energy efficiency and decrease ship emissions, and one of the effective operational measures is trim optimization, which is a feasible measure because it does not necessitate ship structural modification or engine advancement, but it can reduce the ship resistance and decrease fuel consumption. The study of trim optimization can be implemented by conducting experimental tests, but it is a difficult, expensive method and consumed more time. Therefore, the present paper proposes a numerical method to predict the optimum trim which achieves the minimum ship resistance and lower fuel consumption. The current paper investigated two types of ships as a case study, bulk carrier, and container ship. The optimization process has studied several trim conditions, ship drafts, and speeds. The results showed that positive trim (trim by bow) have an increasing effect on fuel consumption, while the negative trim (trim by stern) have a decreasing effect on fuel consumption. Fuel-saving based on using optimum trim at each speed is a significant quantity to be benefited as it would reduce the operating costs and increase the energy efficiency.