Resumen
In the FP7 project GRIP, partners have extensively studied Energy Saving Devices which improve the propulsive efficiency of ships. The research has focussed on an early assessment of the performance, yard processes for the installation of an ESD, structural issues related to ESDs, and the hydrodynamical working principles of ESDs. All the work came together in the final demonstration of the efficiency gain of an ESD on Uljanik built bulk carrier MV Valvoline. To demonstrate the ESD design procedure and the potential performance gain of ESDs, a design competition was held between MARIN, HSVA and Vicus who designed a pre-duct, pre-swirl stator and rudder bulb respectively. Designs were evaluated based on the performance improvement, manufacturability and structural issues. The PSS designed by HSVA came out the best with a reduction of required propulsion power. CFD analysis has shown that the PSS creates a pre-swirl resulting in an increase of the propeller efficiency mainly affecting the upcoming blade trajectory. Speed trial procedures were evaluated by MARIN to come to a procedure to evaluate the performance change with a minimum uncertainty. Speed trials before and after installation of the PSS on the bulk carrier were performed in favourable environmental conditions resulting in a performance improvement of 6.8% at a speed of 16 knots. This paper gives an overview of the work performed in the project by all partners resulting in the successful demonstration.