Innovative dual-function SAIL-POD by Velettrica: experimental assessment and performance calibration

Abstract In the frame of the green-deal objectives, many challenges derive from the need to increase the energy efficiency in the marine transportation, thus to reduce the dependency from the fossil fuels. A wide range of solutions are investigated and many efforts are spent to reach the final result. Multiple interventions can be undertaken in the field of ship power-train, ranging from the identification of innovative propulsive systems, up to the development of digital-tools dedicated to the preliminary propeller design, both tailored to the specific application, namely to the ship geometrical and operative characteristics. The present work deals with the experimental campaign addressing the performances of the Velettrica SAIL-POD device performed at the CNR-INM towing tank. It is a propulsive system with an innovative variable blade-pitch mechanism, with a dual propulsive/regenerative use, conceived to propel a sail-boat and to recover the energy whilst sailing. An automated procedure, applied to the integrated hull-propeller-engine system, is here presented to define the proper geometrical and operative configuration of the device when it acts as a propeller or as a turbine, under different ship operating conditions. Results demonstrate the technology validation in laboratory of the innovative propulsive system as well as the usefulness of the adoption of digital-tools to enhance the ship performances during the service. The analysis of the propulsive performances in open water condition highlighted the areas of intervention to further develop the Velettrica SAIL-POD system.