Drivers and influences of in-service hull and propeller fouling, and its consequence for shipping's energy demand

Hull and propeller fouling can increase a ship's fuel consumption by 10-40% by adding resistance and degrading propulsion efficiency. This potential for increased fuel consumption explains their relevance both to operational costs and the management of the shipping sector's CO2 emissions. However, despite commercial and environmental protection drivers, fouling and coating performance, particularly using in-service measurements, remain a relatively unstudied topic with the majority of work to date focused on studies of a coating's performance in laboratory or controlled conditions (Townsin (2003), Shultz (2007)).

Important recent progress has been made, led by UCL, on the metrology of in-service hull and propeller performance (Aldous, 2015), with the development of an international standard for the sensors, data collection and data processing (ISO 19030). However, there remains a significant lack of understanding of what drives and therefore can explain measured trends in performance. Factors that are believed to be important include, but are not limited to: the frequency and length of time spent at anchor/berth, the speed when sailing, the area of operation, the ecosystems and marine environment encountered during operation, the specification and quality of the coating, the maintenance of the coating.

Building on existing work, there is a need to improve not only the in-service measurement and explanation of measured trends, but also develop understanding of the interaction between the many different drivers: how do they combine to positively or negatively reinforce the extent of fouling.