Power Estimation Method and Its Validation for Ships with Hybrid Contra Rotating Propeller

In response to the urgent need for reducing greenhouse gas emissions, the Hybrid Contra Rotating Propeller (HCRP) system, which combines a main engine-driven propeller with an electrically driven Podded propeller, has become a promising propulsion system for CO2 reduction. This paper presents a new power estimation method for ships with HCRP and outlines the required model test procedures. This study proposes a power estimation method tailored for ships equipped with HCRP and outlines towing tank test procedures required for validation. The method separately evaluates open water characteristics of each propeller and accounts for interactions between the propellers, pod, and hull. Sea trials on an actual vessel were conducted, including speed trials at constant rotational speed ratios and variation tests. These trials confirmed the method’s ability to predict propulsion performance across a wide range of ship speeds. The estimated error in total output from the main engine and generator was within 5% at low output and more accurate near the design speed for the tested case. Furthermore, the method accurately estimates the relationship between rotational speed ratio and power distribution between the main engine and generator for the pod motor, demonstrating its effectiveness for performance prediction and design optimization of HCRP-equipped vessels.