A number of vessels with electric propulsion have recently been built in Germany, Britain and several other countries. Electric propulsion systems adopted in these vessels, however, do not largely differ from the ones in the earlier stage. They decidedly use Ward Leonard for D.C. system and either synchronous or asynchronous motor system by speed change for A.C. system. In this treatise, I have introduced a new system of electric propulsion which may be adopted for any kind of vessels, because it is very economic from the point of view of initial cost and fuel consumption, and the speed can be smoothly controlled in wide range.
