Answer
International Convention on the Control of Harmful Anti-fouling Systems on Ships
A: 5 Oct 2001; EIF: 17 September 2008
Self-polishing paint, also known as self-polishing copolymer (SPC) paint, is a type of antifouling paint used primarily on ships and other marine vessels. It helps prevent the buildup of marine organisms on the hull, which can reduce drag and improve fuel efficiency. Here’s a more detailed look at self-polishing paint:
How It Works
1.Chemical Composition: Self-polishing paint typically contains biocides (such as cuprous oxide). The copolymer slowly hydrolyzes in seawater, releasing the biocides at a controlled rate.
2.Polishing Mechanism: As the vessel moves through water, the outer layer of the paint wears away gradually, exposing a fresh layer of biocides. This continual renewal process ensures that the antifouling properties are maintained over time.
3.Cntrlled Erosion: The paint is designed to erode at a controlled rate, which can be adjusted depending on the vessel's speed and the duration of its Voyages.
Benefits
• Improved Fuel Efficiency: By preventing marine growth on the hull, the paint reduces drag, leading to
significant fuel savings.
• Extended Dry-Docking Intervals: Ships coated with SPC paint require less frequent dry-docking for cleaning
and repainting, which reduces maintenance costs and downtime.
• Consistent Performance: The self-polishing nature of the paint ensures consistent antifouling performance
throughout its lifespan.
• Thin leached layers=simple cleaning and coating
• Good mechanical properties
Application
Self-polishing paint is typically applied in multiple layers, with the thickness depending on the expected service duration and operational conditions. Proper surface preparation is crucial for the paint to adhere effectively and function as intended.
Considerations
• Environmental Impact: While effective, the biocides used in self-polishing paints can have environmental
impacts. There are ongoing efforts to develop environmentally friendly alternatives with reduced toxicity.
• Cost: SPC paints can be more expensive than traditional antifouling paints, but their long-term benefits
often justify the initial investment.
• Average hull roughness is 20 microns per year.
max hull roughness: New vessel- 120, 8 years- 300-400