Ship Biofoulings

Biofouling on ships has well-documented undesirable consequences. It causes an  increase in skin friction drag, leading to higher powering requirements (or reductions in steaming speed). Such effect has significant implications to the efficiency, economy and emissions of ship transportation.​ Furthermore, it also has negative outcome to the health of marine ecosystems, especially when one factors in the traditional use of biocides in antifouling ship coatings. For this research ​we intend to directly investigate the influence of bio-fouled surfaces on the performance of large operational ships.

AIM
Our main objective here is to understand and reduce the skin friction drag on ships hull due to biofoulings, which can lead to lower emissions and operating costs for marine transport. We intend to provide a methodology and technology that can accurately quantify the penalty (emissions, financial, fuel use etc) due to a given hull fouling condition. This will permit the maritime industry to make a more informed decisions in terms of operations (this could be at a regulatory or operational level).

METHOD
​A Laser Doppler Anemometer (LDA) and optical access is installed inside the double bottom  hull of a ship to measure the velocity gradient in the turbulent boundary layer formed over the ships hull. From the velocity gradient we can directly calculate the increase in skin friction drag due to the growth of biofouling. This will be monitored (along with other key data - GPS coordinates, velocity, sea-state, fuel usage, draft etc) during the course of the inter dry-docking period. The ship operates between Merak and Bakauheni (Indonesia). The LDA experiment is accompanied by lab based experiment.

RESULTS
 I. K. A. P. Utama, B. Nugroho, F A. Prasetyo, M. Yusuf, M. L Hakim, I. K Suastika,  B. Ganapathisubramani, N. Hutchins, J. P. Monty. (2021). The effect of cleaning and repainting on the ship drag penalty. Biofouling.   DOI: 10.1080/08927014.2021.1914599

EXPERIMENT FIGURES