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a) Soluble matrix/ ablative AFS 
Soluble matrix coatings have a binder implied that dissolves in seawater causing hydration and 
ultimately release the associated biocide. They have a life span up to 36 months (Georgiades et 
al. 2018). 
b) Insoluble matrix/ contact leaching/ diffusion AFS 
These coating types contain an insoluble binder with a high concentration of biocides. These 
biocides are released through diffusion and usually have a high initial release rate with a 
subsequently strong reduction in course of time. Their life time lasts up to 18 months (Georgiades 
et al. 2018). 
c) Self-polishing copolymer (SPC) coating systems 
SPC’s degrade due to hydrolysis which causes a biocide release when the ship is moving. The 
coatings contain usually copper, zinc, and silyl acrylate and work effectively for up to 60 months 
(Georgiades et al. 2018). 
d) Metallic coating systems 
As mentioned above, metallic coating systems are not the most common used AFS’s on ships 
and are more often used for offshore and fixed installations. Their life span is up to 20 years and 
they are based on copper or a copper-nickel mixture and also contain metal particles (Georgiades 
et al. 2018). 
e) Foul release coating systems 
These usually silicone-based coating systems aim to impair the adhesive attachment of biofouling 
by a “self-cleaning” process. To enable a sufficient biofouling protection, the fouling release 
coating systems require a high-activity and a medium- to high vessel speed (Georgiades et al. 
2018). 
f) Mechanically resistant coating systems 
These coatings do not contain measures or biocides to prevent biofouling settlement or growth. 
They are hard and highly durable to withstand e.g. the abrasion caused by drifting ice in winter 
time. Ships coated with these mechanically resistant coating systems require regular in-water 
cleaning to keep them free of macrofouling (Georgiades et al. 2018). 
2.1.1 Biocidal AFS 
Despite of known advantages of biocide-free solutions, biocidal antifouling coatings still represent 
at least 90% of the hull coating market for commercial vessels (Oliveira & Granhag 2020). 
As mentioned above, biocidal AFS’s present an environmental risk. They are built to release 
biocides continuously with a leaching rate that creates a toxic surrounding for organisms and 
hamper their attachment to the ship hull and niche areas (Morrisey et al. 2013). 
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