Author(s): Trodden D, Woodward MD
Abstract: One of the most significant current topics in the shipping industry is the reduction of greenhouse gas (GHG) emissions, with the IMO introducing mandatory mechanisms intended to ensure energy efficiency standards for ships. Ship’s propellers are usually optimised around a design point, taken at steady dead-ahead design speed. However, in the day-to-day operation of the ship, the loads on the propeller are heavily influ- enced by the manœuvring performance including the ship’s response to its environment. This paper focuses on the development of a methodology for improved propeller efficiency by ‘de- sign for in-service conditions’; rather than trial conditions. The objective of the overall study, is to determine if GHG emissions can be reduced by designing for more realistic operating conditions. Methods are derived for determining the propeller loading characteristics in the manœuvring motion of surge, sway and yaw. Using this model, different scenarios can be developed, representing different shipping routes with different ship types. By the examination of the subsequent flow regime experienced on the propeller, and as a function of the mission profile, the design can be optimised for a more realistic condition. Conclusions are drawn on power requirements for in-service conditions, compared to that of trial.