RightShip introduced its greenhouse gas (GHG) rating in 2012, and chief executive Steen Lund likes to say — tongue in cheek — that the International Maritime Organization's recent steps to evaluate emissions are a "tacit approval" of its approach.

The Singapore ship vetting outfit's initial rating for newbuildings was similar to the IMO's Energy Efficiency Design Index, which was passed in 2011 and in its first phase required vessels to be 10% more efficient.