Who should read this paper? Business people and researchers with an interest in generating renewable energy from marine currents will find this paper to be of interest. It will also be of interest to autonomous subsea instrument developers who are looking for an economical means to power their devices. Why is it important? A Savonius rotor is simple, easy to build and robust. It will accept flow from all directions, and has a high starting torque. However, this type of rotor is characterized by relatively low efficiency and slow running speed. The work reported here is part of a larger effort to develop, deploy and power autonomous measuring devices on the deep seafloor. This component of the work is focused on the potential of using a Savonius rotor to power such devices. An important goal in the effort was to see if scaling laws could be used to accurately predict prototype performance. Results reported here indicate that scaling laws can be used to present data for Savonius water current turbines in a form that would allow one to predict full scale behaviour. Two simple theoretical models were developed for turbine power: one based on impulse momentum and the other based on wake drag. The data presented suggest that, for an actual turbine, impulse momentum is the dominant mechanism. The authors postulate that these results will be useful in helping to model the dimensions of turbines for various applications. They also believe that these results prove that one can accurately estimate the amount of power that can be harvested at different flow speed from the ocean current. Completion of the larger effort is scheduled for the end of 2012, including development of a functional energy conversion unit for marine current. About the authors Nahidul Islam Khan is a PhD candidate in the Faculty of Engineering and Applied Science at Memorial University. His research interest is in the development of a current-driven energy conversion system that is robust and inexpensive. Tariq Iqbal is an Associate Professor at Memorial University with particular interest in the design of control systems and comparison of control strategies for hybrid energy systems. Michael Hinchey is a professor in the Faculty of Engineering and Applied Science at Memorial University with an interest in the development of inexpensive, robust AUVs that could be used for survey and inspection type missions. Vlastimil Masek is an Assistant Professor of Electrical and Computer Engineering at Memorial University with an interest in supervisory control and data acquisition, remote sensing, oil and gas process control, and electronic instrumentation. His current research is in the area of smart instrumentation for applications in the oil and gas industries. Turbomachinations Khan, Iqbal, Hinchey, and Masek present power data for two types of Savonius rotor when deployed as a water current turbine. Nahidul Islam Khan Tariq Iqbal Michael Hinchey Vlastimil Masek 92 The Journal of Ocean Technology • Reviews & Papers Copyright Journal of Ocean Technology 2010 NOT FOR REPRODUCTION brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Memorial University Research Repository