Expanding the application of ESDs to ships with CPP

In FP7 project GRIP, MARIN and Wärtsilä with partners worked on designing and optimising Energy Saving Devices (ESDs) for ships fitted with a Fixed Pitch Propeller (FPP). This resulted in the full scale demonstration of nearly 7% reduction in required propulsion power on a bulk carrier. To increase the total impact of ESDs on shipping energy consumption in additional markets, the next step is to investigate the energy saving potential of ESDs for ships with a Controllable Pitch Propeller (CPP). Most effective ESDs modify the swirl in the inflow (pre-swirl) or outflow (post-swirl) of the propeller. The amount of swirl strongly depends on the pitch of the propeller. As this is variable in a CPP, an additional optimisation challenge is added for ESDs for CPP.

This is done by designing, simulating and testing an ESD design for Grimaldi vessel Grande Colonia. A pre-swirl device was designed by MARIN and a post-swirl device by Wärtsilä. Calculations showed better fuel saving potential for the pre-swirl device. Model tests are being performed, including model tests in waves to establish the dynamic loads on the stators in a seaway. After the model scale testing is completed, Wärtsilä will produce the ESD to be installed on the Grande Colonia for dedicated demonstration trials.