Anti-fouling paint is used under the water line of the ship to prevent marine growth on the ship’s hull. Tri-butyl-tin (TBT) has been used as the main toxin against marine growth.
However, it has been found that TBT creates problems for marine flora and fauna. For this reason, nowadays, self-polishing copolymer or self-eroding paint, which relies on a weaker biocide and different method of delivery, are used.
The anti-fouling paint is so designed that it gets removed gradually by the flow of water. As the ship moves forward in the seawater, the anti-fouling paint gets eroded at a very slow rate. This brings fresh layer of biocide to the surface, which acts as toxin for the marine growth and prevents it to stick to the hull’s surface.
Factors considered while selecting the anti-fouling paints:
- Speed of the vessel: The anti fouling paint must be selected depending on the service speed of the vessel, so that the removal of paint takes place at a correct rate. A harder paint compound will be required for the vessels with a higher service speed.
- The dry-dock of the vessel : If the ship is dry-docking once in two and half to five years, it will have an influence on the thickness of the anti-fouling paints. Greater the time between dry docks, thicker will be the paint layer.
Note : Vessel should not be kept stationary or should not be operated at reduced speed, this will affect the removal of the paint which will not be at a required rate. Hence anti-fouling will not be effective.
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