Existing Vessel Design Index (EVDI)

The Existing Vessel Design Index (EVDI) is RightShip’s measure of a ship’s theoretical design carbon intensity, expressed in grams of CO2 per tonne-nautical-mile. RightShip developed it in 2012 so that ships with no regulatory EEDI could be placed on the same axis as ships that have one, since the IMO design index reaches only ships contracted on or after 1 January 2013.

Its published formula is term for term the IMO attained-EEDI equation, and RightShip states its data is, as far as practicable, in line with the IMO guidelines for EEDI calculation. What separates the two is provenance rather than mathematics: an attained EEDI is populated from a class-approved Technical File with sea-trial speed-power data, while an EVDI falls back through a ranked hierarchy that ends in IHS records, IMO default assumptions and sister-ship data.

The full article will set out the formula term by term, the four-level data source hierarchy, the distinction between a verified and an unverified index, the conservatism DNV GL measured in its 2015 review, and the index’s role as the fallback input to the RightShip GHG Rating since EEXI took precedence for existing ships in December 2023.