Using a Ship's Propeller for Hull Condition Monitoring

Abstract

As a ship’s hull condition degrades due to marine fouling, more power and fuel are needed to maintain service speeds. A by-product of the increased fuel consumption is increased Green House Gas emissions. Rising fuel costs, hull maintenance expenses, and mounting environmental regulations make hull condition monitoring a crucial tool for prudent ship operators to eliminate energy waste due to hull fouling, reduce carbon emissions, and eliminate the carriage of invasive species between ports. Methods for using a ship’s propeller as a power absorption dynamometer employ the propeller as a measuring instrument to estimate either speed or power. The calibration is typically performed for clean hull conditions, allowing the resulting propeller model to be used to track ship performance degradation due to hull fouling against a standard “clean-hull” baseline. The propeller power absorption technique is presented, along with the salient results of using it to monitor two Navy sisterships over a yearlong time period. This information may be useful for Navy decision makers responsible for hull/propeller maintenance and hull paint selection.