An Application of the Tank Test with a Model Ship for Design of Ship Propulsion Plant System

Abstract

Engine power reduction is now regarded as the most efficient and easy realisable measure to improve the Energy Efficiency Design Index, introduced by the IMO. However, there is a concern regarding the sufficiency of propulsion power to maintain manoeuvrability of ship in the adverse sea, and so the IMO also set the interim guideline to assess Minimum Propulsion Power (MPP). As a result of these streams, it has never been more important to evaluate the performance of the ship in actual sea conditions, even including engine characteristics deeply. Here, as a method to validate or investigate designs of ship propulsion plant system in the initial design stage, the authors have developed an intelligent motor system for the ship model test, called as a Marine Diesel Engine Simulator (MDES). The MDES consists of the cycle mean value model of engine, a speed governor and motion equation of propeller shaft. The MDES simulates the response of the engine model in real time, based on the measured propeller torque and speed, and manage the rotational speed of the motor as the calculated response. In this way, the engine matching, requirement on MPP, speed governor settings, etc., can be easily validated at the design stage without the need for full-scale tests. This paper briefly introduces the tank test methodology and then discusses the test results of propulsion plant responses in regular waves at different speed governor settings in details.