Estimating the impact of new-generation antifoulings on ship performance: the presence of slime

Abstract

Due to the phase-out of TBT-SPCs imposed by the International Maritime Organization, new-generation antifoulings are set to replace 80% of the existing antifouling market. Two types of coatings are claimed to offer satisfactory performance over five years: tin-free SPCs and foul-release coatings, which were both commercially introduced in the mid 1990s. This paper gives an overview of the research at the University of Newcastle upon Tyne which compares the drag, boundary-layer and roughness characteristics of both coatings when newly applied. It was found that foul-release coatings offer less drag than tin-free SPC, by an amount which depends on the quality of application and which has been related to the respective differences in roughness characteristics. Assessments have shown that foul-release surfaces are very effective against macrofouling organisms, but that the surface is covered by slime films when the vessel returns to drydock. A literature review on the effect of slime films on ship resistance shows that slime films have a significant effect on drag, but in turbulent flows the effect is likely to remain limited because of detachment processes. Further research is underway to investigate this.

Rhodobacteraceaeare the key members of the microbial community of the initial biofilm formed in Eastern Mediterranean coastal seawater

“…Biofouling is a common phenomenon in aquatic environments. Biofilms are formed naturally on flora and fauna (Rao et al ., ; Egan et al ., ), sediments (Heijs et al ., ) and man‐made structures such as ships (Candries & Atlar, ), pipelines (López et al ., ), nanofiltration membranes (Ivnitsky et al ., ) and reverse osmosis membranes (Vrouwenvelder & van der Kooij, ). Some of these biofilms can cause costly damages such as corrosion (Al‐Malahy & Hodgkiess, ), drag force of ships (Candries & Atlar, ) and a decrease in desalination process effectiveness (Vrouwenvelder & van der Kooij, ).…”

“…Biofilms are formed naturally on flora and fauna (Rao et al ., ; Egan et al ., ), sediments (Heijs et al ., ) and man‐made structures such as ships (Candries & Atlar, ), pipelines (López et al ., ), nanofiltration membranes (Ivnitsky et al ., ) and reverse osmosis membranes (Vrouwenvelder & van der Kooij, ). Some of these biofilms can cause costly damages such as corrosion (Al‐Malahy & Hodgkiess, ), drag force of ships (Candries & Atlar, ) and a decrease in desalination process effectiveness (Vrouwenvelder & van der Kooij, ). In desalination plants, biofilm can form on various components employed in the process (pipes, holding tanks, membranes) and tremendously increase operational costs, and consequently water prices (Schneider et al ., ).…”

Testing the impact of biofilms on the performance of marine antifouling coatings

“…There is a growing body of work looking at how biofi lms affect a coating's performance in terms of hydrodynamic drag (WHOI 1952;Watanabe et al 1969;Loeb et al 1984;Mihm et al 1988;Candries et al 2003;Valkirs et al 2003;Holm et al 2004;Schultz 2004) and biocide release rate (WHOI 1952;Mihm et al 1988;Valkirs et al 2003;Yebra et al 2006b;Howell 2007), although there has been very little work done in the last 20 years investigating how species diversity in biofi lms is affected by biocide concentrations from AF coatings (WHOI 1952;Dempsey 1981;Tang et al 1998;Boivin et al 2005;2006;Cassé et al 2006;Howell 2007), or by changes in shear stress (Beyenal et al 2002;Rickard et al 2004;Tsai 2005;Cassé et al 2006;Howell 2007). Species diversity could be important as new antifouling technologies based on micro-textured surfaces will need to address the community composition of biofi lms in order to be fully successful.…”

Surface sensing and stress-signalling inUlvaand fouling diatoms – potential targets for antifouling: a review

“…Nonbiocidal coatings such as those based on PDMSe have been effective in reducing fouling by macroalgae and invertebrates (Candries et al 2003). These hydrophobic, low modulus coatings do not prevent colonisation by fouling organisms but are designed as ''fouling-release'' coatings; that is, they ''release'' adhered organisms by the hydrodynamic forces generated when a ship moves through the water.…”