Maximum Continuous Rating(MCR):
It is the maximum output power for the engine running continuously under safe conditions. Contractual maximum continuous rating is the rating according to the contract agrees upon.
Standard Continuous Rating or normal rating(SCR):
It is the output power at normal service speed corresponding to economical efficiency, thermal efficiency, mecchanical efficiency and easy maintenance.
It is the maximum output power which the engine can run whist running in astern directions.
It is a short term effective power in excess of the rated power with the same set of auxiliaries, under the same service conditions, which can be used periodically for a limited interval only.