Abstract
While there are many advantages with electric propulsion vessels, energy loss is considered as its most significant disadvantage. Therefore, the minimization of energy loss and the improvement of the ship’s propulsion efficiency are important elements. There are two conceivable elements to improve propulsion efficiency, one is to decrease hull resistance, and the other is to increase the propeller efficiency. Contra-Rotating Propeller (CRP) is one of the solutions to improve the efficiency of propulsion systems, and the tandem type CRP, which is an azimuth pod propeller installation behind the CPP, is considered as an example of practical application.
In this paper, an electric propulsion system with the tandem CRP is introduced.
By designing a hybrid CRP system that operates a CPP driven by a diesel engine and an azimuth pod propeller driven by an electric motor, the reduction of the percentage of energy loss and the minimization of fuel consumption were made possible. Nakashima’s pod propulsion system is based on CPP’s and side thrusters’ technology. Propeller pitch was determined using an NMRI1) CRP program. Since the azimuth pod propulsion system can be used as a stern thruster as well, with this propulsion system, not only an improvement in propulsion efficiency, but also an improvement in maneuverability can be expected.
1): National Maritime Research Institute
