Klaveness Combination Carriers (KCC) has initiated several projects focusing on marine growth to seek easier ways to monitor and inspect the state of hull growth, to prevent marine life growing on ships in the first place, and to remove existing hull growth.
Biofouling, or hull marine growth, has bothered both shipowners and boat enthusiasts throughout history, and despite the gamut of today’s technologies, algae and barnacles will invariably continue to grow on rudders and hulls, increasing the additional emissions of greenhouse gases by well over 10%.
KCC has set itself the target of reducing average absolute fuel consumption and CO2 emissions per vessel by a minimum of 15% by 2022, and reducing the growth of marine organisms on hulls is seen as a low-hanging fruit.
The first stage was to monitor hull growth by increasing the frequency of hull inspections in port. This gives a better indication of the need to undergo a manual hull cleaning and propeller polishing.
But more inspections require more time and cost. KCC is currently piloting an underwater drone from Blueye on two of its vessels. Blueye’s technology allows more frequent hull inspections and allows KCC to make better visually informed decisions on the vessel’s need for hull and propeller cleaning.
In addition, KCC is involved in a research project to use machine learning to predict the state of hull growth based on the type of coating, time since last cleaning, seawater conditions etc. By looking at the increased fuel consumption after idling, the aim is to predict the growth rate of marine organisms, and by adding the seawater temperature as a parameter, the change in growth rates between arctic, temperate and tropical waters.
KCC is testing an ultrasound device to prevent the initial growth of biofilm on the propeller. The Blueye drone is being used to document the effectiveness of the ultrasound device to keep the propeller free of marine growth.
KCC is also testing a wide range of hull coatings, including slow-releasing biocides and advanced silicone-based hull coatings.
But eventually some form of manual cleaning is required. KCC is testing a novel technology developed by the Norwegian company Shipshave AS. Shipshave’s In-Transit Cleaning of Hull (ITCH) is a semi-autonomous hull cleaning robot, which is tethered to a winch on the foredeck of the vessel.
As the ship sails, the water flowing over the hull provides the energy for the robot to clean the hull using soft brushes that move up and down the side hull, travelling with a defined pattern with controlled brush forces.
Removed growth falls onto the ocean floor and creates no harm to the ecological system. The focus of the ITCH is to remove the initial layer of biofilm to prevent growth of harder biofouling such as barnacles, but it is also proven to remove settled fouling.
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