antifouling

Antifouling refers to the technologies and practices used to prevent or control biofouling on submerged surfaces. Biofouling is the unwanted accumulation of organisms such as algae, barnacles, bryozoans, and mussels, which can increase hull roughness, weight, drag, corrosion, and maintenance costs. Applications include ships and boats, offshore platforms, aquaculture nets, pipelines, and other submerged structures.

Historically, antifouling relied on toxic biocides released from coatings to deter settlement. Organotin compounds, notably tributyltin (TBT), were widely used but caused significant ecological harm, including adverse effects on non-target marine life. International regulation has restricted and phased out such compounds, leading to the adoption of copper-based biocides, zinc, and non-biocidal foul-release or low-adhesion coatings. The International Convention on the Control of Harmful Anti-fouling Systems (AFS Convention) governs ships' antifouling systems and sets performance standards and discharge controls.

Coating types include biocidal systems that release active substances, fouling-release coatings with low surface energy that reduce adhesion, and self-polishing copolymers that shed slowly to renew the surface. Silicone-based non-stick coatings offer very low adhesion, while non-toxic or environmentally friendly options aim to reduce ecological impact and regulatory risk.

Environmental considerations focus on minimizing toxicity to non-target organisms and preventing persistence or bioaccumulation. Regulatory frameworks require testing, certification, and monitoring of antifouling products and may restrict certain chemistries and active ingredients.

Current trends emphasize reduced-toxicity solutions, hull-cleaning and maintenance best practices, and integrated strategies combining coatings with anti-fouling technologies and hull design to improve fuel efficiency and reduce emissions while complying with environmental regulations.