Antifouling innovations: a plan for ecological boating


By Alex Smith


The antifoul game is changing – from biocide-free solutions to UV panels and robotics – new antifouling innovations are placing a renewed focus on an economical and ecological boating future.


Marine coatings, particularly those used below the waterline, have an extremely important job to do. With around 4,000 potential fouling organisms in the world’s oceans, from algae and anemones to barnacles and mussels, effective antifoul practices are vital. Antifouling does not just maintain hull efficiency and minimise costs but can also help prevent the spread of non- native species to other regions.


Given that a heavily fouled hull can increase drag by around 40 per cent, the environmental impact in terms of emissions is also critical. According to Chris Birkert, marine segment manager at AkzoNobel, a heavily fouled container ship could potentially “increase its CO2 emissions in a single year by up to 16,000 tonnes for a 10 per cent speed reduction and up to 64,000 tonnes if you want to retain its original speed”.


Effective coatings and antifoul innovations are vital to sustainable boating, both from a financial and an ecological perspective. And while, in the past, the relative absence of legislation regarding toxic content in antifoul has made that job easier, the game has changed. With public attitudes, political intent and international legislation now broadly aligned in their commitment to cleaner seas, both commercial shipping and recreational boating are searching for biocide-free solutions that are as ‘friendly’ as they are effective.


78 | The Report • September 2022 • Issue 101


This article first published in Marine Industry News Spring 2022.


STAY SLIPPY


Silicone-based foul-release coatings have been garnering plenty of attention and with good reason.


Rather than releasing harmful biocides into the environment, silicone-based coatings are designed to create a slippery surface, thereby preventing the attachment of organisms and helping hulls self- clean underway. With around two decades of effective use behind them, Propspeed’s biocide-free, silicone- based coatings are now available for transducers, as well as props, running gear and subsurface metals. Hempel’s Silic One is another biocide- free fouling release system, which is based on a combination of silicone and hydrogel. While longevity is not generally as strong as other techniques, most mainstream silicone foul- release coatings exhibit an effective service life of between 12 and 24 months.


METAL FRAME


Coppercoat uses a combination of a solvent- free water based epoxy resin and high purity (99 per cent) copper. Each litre of resin is impregnated with two kilos of ultra fine copper – the maximum allowed by law. On immersion, sea water attacks the exposed pure copper powder, causing the formation of cuprous oxide. This antifouling agent deters growth until the surface degrades further to become cupric hydrochloride. This final copper form is highly unstable, and is washed away by the movement of the yacht, thereby removing any accumulating silt or slime underway.


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