The invention relates to an apparatus (100) for determining an optimal route of a maritime ship, wherein the maritime ship is to depart at a predetermined departure location, wherein the maritime ship is to arrive at a predetermined destination location, and wherein the maritime ship is using propulsion to move ahead. The apparatus (100) comprises a database (101) configured to store at least one, or a combination of optimization constraint parameters, wherein the at least one optimization constraint parameter comprises a predetermined constant shaft power of the propel shaft. The apparatus (100) further comprises a processor (103) configured to execute a multi-objective route optimization algorithm based on the predetermined departure location, the predetermined destination location, and the at least one, or a combination, of optimization constraint parameters in order to obtain the optimal route of the maritime ship. The apparatus (100) may further comprise a communication interface (105) configured to transmit navigational data over a communication network.