Here are some steps that can make commercial shipping vessels more energy-efficient:
Hull form: Changing hull design to produce less resistance.
Propeller technology: Using larger propellers with higher efficiency; also installing casings around propellers to direct the water flow across the propeller more effectively.
Hull paint technology: Creating antifouling paints that have less friction through the water.
Engine technology: Using longer-stroke engines fueled by heavy fuel oil and marine diesel to reduce energy consumption and emissions.Source: Cargill Inc.