Application of automatic position information data in vessel performance analysis

Abstract

When a ship’s hull and propeller become fouled, the performance of the ship degrades. In these cases, the ship requires more engine power and fuel to reach the same operating speeds. Performance monitoring can be used to analyze the performance of a ship over time and help determine when hull and propeller cleanings should take place. Building on a previous thesis, two performance analysis models were developed in MATLAB. The techniques used in the models developed in this thesis are based upon techniques from the International Towing Tank Conference (ITTC) 1978 performance prediction method and the International Organization for Standardization (ISO) guidelines for assessment of speed and power trials. Both models rely on publicly available Automatic Information System (AIS) data to determine speed and location information. Both models use independent hindcast data for wave conditions, wind conditions, and water properties during the voyages. Both models also filter the data to remove situations which are undesirable to use for performance analysis, such as acceleration and maneuvering. The first model relies on daily fuel consumption readings and analyzes the performance on a per-noon-report basis. The second model relies on onboard auto-logged measurements for engine torque and RPM, and analyzes the performance on a per-auto-logged-period basis. A fuel index is calculated for each analysis point, which allows for tracking of the performance of a ship over time.