EEDI Reference Line

The EEDI reference line is the logarithmic curve fitted to the attained EEDI of ships built between 1999 and 2009, defined per ship type under MEPC.215(63). It expresses the average design efficiency of that baseline fleet as a function of capacity. The required EEDI and the required EEXI are both this line reduced by a phase or ship-type factor, so the reference line is the anchor for every design and existing-ship efficiency requirement under MARPOL Annex VI Chapter 4.