The importance of maintaining a smooth and clean hull free from biofouling has been outlined in a new report from IMO.
The report - Analysing the Impact of Marine Biofouling on the Energy Efficiency of Ships and the GHG Abatement Potential of Biofouling Management Measures highlights that a layer of slime as thin as 0.5 mm covering up to 50% of a hull surface could trigger an increase of GHG emissions in the range of 25 to 30% depending on ship characteristics, its speed and other prevailing conditions. These percentages can be much higher for more severe biofouling conditions, depending on the type of ships and other parameters.
In addition to analyzing the impact of biofouling on ship efficiency and how current industry practices for biofouling management impact ship efficiency, the study presents results from seven scenarios (or anti-fouling strategies) in relation to a reference ("always clean") of a target vessel (bulk carrier), between dry-docking periods. These results demonstrate the magnitude of fuel, CO2 and cost savings that can be achieved by keeping this ship as clean as possible from biofouling. Biofouling management is one important contributor to the overall operational efficiency of ships and should be considered by shipowners to achieve IMO's Carbon Intensity Indicator (CII) rating indicator that measures vessel carbon intensity over time.