Existing Design Trends for Tankers and Bulk Carriers: Design Changes for Improvement of the EEDI in the Future

To get an idea of the reduction in propulsion power and associated emissions by varying the speed and other ship design main parameters, a generic model for parameter studies has been developed. With only a few input parameters of which the maximum deadweight capacity is the primary one, a proposal for the main dimensions and the necessary installed power is calculated by the model. By adjusting the vessel design, i.e. the main parameters, and varying the speed it is possible to observe the influence of the different parameters on the power demand. The model can be used to calculate exhaust gas emissions from bulk carriers and tankers, including emissions of carbon dioxide (CO2). A calculation procedure for estimating the Energy Efficiency Design Index (EEDI) is also included in the model. The IHS Fairplay World Fleet Statistics for vessels built in the period 1990–2010 are used as a basis for the generic modelling. A comprehensive regression analysis has been carried out to find the formulas to be used as a basis for the model. Furthermore, it was found during the analysis that the design trend of bulk carriers and tankers has moved in a wrong direction seen from an energy saving point of view. The block coefficient has increased during the last twenty years while the length displacement ratio (L/displ.volume 1/3 ) has decreased over the same period. These two design changes have resulted in an increased EEDI. This development must be changed in the coming years when the EEDI shall be reduced gradually, ending in a 30 per cent reduction in 2025. An overview of the historical development and the necessary design changes will be documented here, including a complete list of the formulas for the main dimensions found by the regression analysis.