An EEDI based method to better the selection of form and propulsion parameters and improve energy efficiency during preliminary designs of single screw seagoing general/bulk cargo ship

Abstract

The third phase of the Energy Efficiency Design Index (EEDI) regulations, which came into force in 2022, states that new ships should reduce their emissions by at least 30% compared to the minimum energy efficiency level (EEDI baseline) set by the IMO's MEPC in 2013. Apart from its vital role in decarbonizing the global fleet and improving the transportation efficiency, the EEDI that is considered herein is a measure of vessel's mechanical performance. A simplified EEDI (SEEDI) is used to judge a series of designs in order to identify all possible efficient designs and to select the best option. A code was employed to iterate over all practical ranges of hull and propeller parameters to extract complete designs from methodical design and propeller series. All possible methods of manipulating form and propulsion parameters that might lead to reducing the SEEDI were investigated. The modifications were made while taking into consideration the practical and economical ranges of the non-dimensional ratios and form coefficients. Compared to the use of energy saving devices and slow steaming, significant reductions (up to 25%) in the SEEDI have been achieved after applying the proposed method.