Consideration about the Impact of Bottom Fouling of the Light Alloy Medium-Sized Vessel on the Vessel Speed and Fuel Oil Consumption

Aiming at reducing the vessel operation cost associated with the fuel consumption and contributing to the more efficient vessel operation with a view of energy saving, the authors, examined the impact of bottom fouling on the speed decrease and increased fuel oil consumption. Also the authors examined the effect of the alteration of the ship bottom paint on the improvement of speed and fuel oil consumption. The authors examined the level of bottom fouling and the change over the months after undocking in speed tests with the light alloy medium-sized vessel, T/S KAKUYO-MARU of Faculty of Fisheries, Nagasaki University. As a result, the following points became obvious. (1) The significant deterioration was seen in none of the speed and fuel oil consumption until June, four months after undocking. The speed decrease and increased fuel oil consumption came to be seen in and after August. (2) The authors compared the hydrolyzable bottom paint with the conventional one about the variation of the state of fouling, speed at each engine speed, and fuel oil consumption. The bottom fouling in 2012, when the bottom paint was altered, was considerably decreased in comparison with that in 2010 and 2011 when the conventional bottom paint had been used. Therefore, it would appear that the new bottom paint had an effect.