What is it about?

This study proposes alternative formulations of the ship-specific correction factor (fjRoRo) pertaining to Ro-Ro cargo and Ro-Ro passenger ships, as defined in the Energy Efficiency Design Index equation according to the International Maritime Organization Resolution MEPC 245(66). The alternative formulations were derived by studying a large sample of Ro-Ro cargo ships and Ro-Ro passenger ships, built between the years 1990 and 2012. The estimation of ships’ resistance and powering was conducted by application of Holtrop’s method. The obtained formulae’s exponent values were compared with the corresponding ones from latest International Maritime Organization studies on Energy Efficiency Design Index and they appear to better represent the energy efficiency and environmental impact of the operating fleet of Ro-Ro cargo and Ro-Ro passenger ships. Derived formulae may also be used in the frame of parametric design optimization of Ro-Ro ships.

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Why is it important?

The obtained formulae’s exponent values were compared with the corresponding ones from latest International Maritime Organization studies on Energy Efficiency Design Index and they appear to better represent the energy efficiency and environmental impact of the operating fleet of Ro-Ro cargo and Ro-Ro passenger ships. Derived formulae may also be used in the frame of parametric design optimization of Ro-Ro ships.

Perspectives

This study proposes alternative, improved values for the exponents of the correction factor fjRoRo pertaining to Ro-Ro cargo and Ro-Ro passenger ships in the EEDI calculation. For both ship types under study, a non-linear relationship between the main engine power PME and the main engine power SDV SDVPME proved superior to others and of higher correlation with respect to the representativeness of the employed ship sample. Our linear approach, developed in parallel in this study, led as well to a higher (even marginally) correlation coefficient, when calculating the required EEDI reference line for a large sample of ships, compared to the corresponding one adopted by IMO. The observed diversity in the quality of fitting and the variation in the exponent values raise some justified questions regarding the maturity of the EEDI reference lines for some ship types, adopted so far by IMO. The obtained parametric relationships between the powering of Ro-Ro cargo and Ro-Ro passenger ships and of basic ship design parameters can generally be exploited in parametric ship design optimization procedures in the frame of a holistic approach to ship design.

Professor Apostolos Papanikolaou
National Technical University of Athens

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This page is a summary of: On the Energy Efficiency Design Index of Ro-Ro passenger and Ro-Ro cargo ships, Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment, August 2016, SAGE Publications,
DOI: 10.1177/1475090215613815.
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