Superconducting Marine Propulsion Power

Over the last 25 years a large amount of research and development has been undertaken on the application of superconductors to marine propulsion systems and a number of superconducting homopolar motors and generators were constructed between the mid 1960s and the early 1980s. The paper reviews this work and shows that the technology had almost reached the point where industrial exploitation could have commenced. The reason why these machines did not reach the market place is discussed together with the impact which the recently discovered higher temperature superconductors may have upon future developments. Reference is made to a new ship which has been constructed in Japan and which derives its thrust directly from electrical energy using superconducting magnets in an engine based upon magnetohydrodynamics (MHD). With the exception of the MHD ship and the programme in the United States all of the work on d.c. machines described in this paper has been carried out by or under the direction of the author.