A study on the matching problem of engine, propeller, and ship hull under actual service conditions

In ship design, the matching of engine, propeller, and hull is an analytical process to establish the optimal operating mode so that the engine works safely with full power and the lowest fuel consumption, and a ship reaches desired speed. In theory, the operating process of the engine, hull, and propeller is usually expressed by their characteristics, and the matching problem is solved by finding the intersection of these characteristics. The problem here is that the above characteristics are determined under design conditions, corresponding to the standard technical conditions of the engine, hull, and propeller, however, all of these will be changed under actual service conditions, leading to a change in the position of the defined design match points and thereby greatly affect the safety and performance of the ships. This paper presents a new approach to determining the actual characteristics of the engine, hull, and propeller and how to use them to solve the matching problem under service conditions. This study was verified and validated on three study ships and was also applied to solve the matching problem of the Glory Star tanker. All the obtained results are in good agreement with the published real experimental data for this ship with a power loss of 21.5% under current service conditions, including 6.5% due to changes in propeller characteristics by changing technical conditions of propeller and hull surface, 6.3% due to engine deterioration, and 8.7% due to the engine - propeller mismatch after 5 years of operation.