Merchant shipping remains the largest carrier of freight throughout recorded history due to the economic advantages involved. Optimum management of the global propulsion power may result in large cut down of marine fuel grades, which will in turn benefit environment and the economics of the shipping community. Although, water transport is still the most efficient mode (small ratio of CO2 per cargo ton per mile) the aim is for vessel's further energy efficiency optimization, bunker minimization and in turn reduction of CO2, NOx, SOx. An energy efficiency management scheme cannot be sustained unless a meaningful and practical mode of monitoring is applied.