Fathom World

Mapping the transformation of shipping and the oceans

FeaturedStrategy News

Biofouling Focus: Foul play

There is a lot happening in the exciting world of biofouling. Not only are the coating makers getting increasingly competitive, but the regulators are looking to ban once accepted biocides (cybutryn ) and make clean hulls mandatory.

Danish paints and coatings giant Hempel just released its full year, 2019, results, showing a slight upswing in profits and a corresponding optimism about the future. This is just as well. The Copenhagen-listed group is in the midst of a massive head office expansion, including a new research and development building that still needs finishing.

It is now talking bullishly about acquisitions and market growth, new products and new ways of dealing with the shipping industry as biofouling prevention becomes even bigger business.

Hempel, like the other main hull coating suppliers, is not only focused on the marine and shipping markets, it has coatings for a wide range of commercial, and even domestic applications,  something that has helped during the market swings. But is looking at the marine markets in a new light knowing that sustainability, fuel efficiency and even decarbonisation are key agenda items that they can, and do, have newly developed solutions for.

Hempel is of course pushing its latest Hempaguard hull coating product hard – all the coating makers talk about their products being technologies, mainly due to their complex chemistry and application –  comparing it to other unspecified market products to suggest its superiority. It also points to the 1,700 vessels that have the product on hulls.

The Danish company is also proud of its decision to join a Copenhagen-based think tank talking about how ships can move to a carbon neutral impact.

In a recent press briefing in Copenhagen, Hempel pointed to it being invited to join the Getting to Zero Coalition being driven the Global Maritime Forum, with Hempel head of sustainability Michael Hansen saying that all suppliers  have an interest in getting to zero (carbon neutral) emissions.

“This is a downward trajectory,” he said, referring to CO emissions, adding that while Hempel believes the company can contribute it is unclear exactly how. “It is very likely our products will have to develop, with new solutions. We will have to stretch our thinking along the way”.

The money in clean hulls

There are two reasons for a ship to have a clean hull – it makes for smoother more efficient sailing and it also reduces the chances of spreading invasive around the world.

Both are important, on an economic and environmental front, but coalesce into one important, but always expensive shipowner choice. Which hull coating to choose.

There is no simple answer, and hull coatings is a science beyond most people’s understanding. There are different coatings for different ships, different places of operation and even for different parts a vessel’s hull –  Hempel now has a specific coating for the area around an ship exhaust gas cleaning washwater discharge outlet due to what the company calls aggressive water quality.

The underwater area of a ships hull, the area susceptible to fouling, can be huge, on some of the largest ships about 200,000 m 2 (capsize). This could lead to a lot of extra drag and a lot of risk to the environment. Coating that area with primer, tiecoat and outer repellent coating requires a lot of paint, and a large cost, as well as time in a drydock.

However the cost benefits are also significant according to the coatings makers. All coatings will degrade over time, leading to a build up of slime, algae and then barnacles and other organisms. Hull coatings delay the onset of this, and the more expensive do so for longer, lengthening the period that the vessel can sail without extra drag that requires extra engine power to overcome, and the need for costly hull cleaning.

Hidden problems – Asbestos and Cybutryne

The choice of hull coating has other impacts too. Given the ingredients, it has been suggested that they could fall foul of the ship recycling convention as owners need to list all hazardous materials in a mandatory list, and some coatings are known to contain talcum linked to asbestos. With the European ship recycling regulations demanding that ships list all hazardous materials found onboard, experts have said that owners need to talk to coatings makers to ensure that hull coatings are on the list if they need to be.

Since the ban on tin in coatings the coating industry has found other ingredients to put into the paint,   There is also discussion at the IMO on banning a substance known as cybutryne (C11H19N5S), which is considered to be highly toxic, which may be what is wanted in an anti fouling component. Cybutryne is mainly used to prevent fouling of plants and algae The Sub-Committee finalized a proposed amendment to the IMO Convention for the Control of Harmful Anti-fouling Systems on Ships (AFS Convention), to include controls on the biocide cybutryne, with the ban coming into effect later this year. This is the first amendment to the AFS to be proposed since it came into force in 2008

In some countries (Bermuda, New Zealand, UK, Demark, Sweden ) the use of Cybutryne as an antifouling product has already been restricted, banned or phased out, notably inpleasure an d fishing craft. The EU has also prohibited the marketing of coatings and paints with he compound in them.

 New coatings, new substances, new solutions

Regular Fathom World readers may recal the focus last year on the EU funded Aircoats project which has Horizon2020 money to examine a novel hull coating that aims to biomimic the characteristics of a plant to repel water, creating better (lower) friction and less instances of biofouling.

But already on the market is a solution using ultrasound transducers as an anti-fouling technigue.

Sonihull8 from NRG Marine is an easy to fit system that the firm says is low cost and can be used on any part of a vessel’s underhull area, an important claim given that any superintendent and vessel crew know that biofouling buildup will often begin in those hard to reach areas around water inlets, seachests, rudder mechanisms  and lugs where water flow is erratic and slow that buildup begins.

The company literature says microscopic ultrasound-induced cavitation disrupts the first stages of the food chain without damaging the surface being protected. This action prevents the build-up of algae, slime and bigger more complex organisms on surfaces where biofouling is not wanted.

Similarly, but by completely different methods, there are now coatings that are impregnated with a chemical compound known as Selektope which is made by a Swedish biotech firm Itech. Based on known chemistry, Selektope acts like a temporary drug on barnacle larvae, repelling them from ship hulls with a selektope infused coating.

There are other solutions emerging in the market and as the IMO discusses how to turn the biofouling guidelines into a regulations the issue of how to coat a hull, what to coat it with, and how to then clean a hull will become increasingly important issues.

Keep following the transformation of biofouling on Fathom.World to keep up to date.

About Author

Craig Eason Stockholm
Craig Eason is the owner and editorial director of Fathom.World. He has a background in the shipping industry having started his career as a cadet on oil tankers and gas carriers before becoming a navigating officer on a range of vessel types. A change in career, with ensuing university studies, and he has now gained 20 years experience in written and broadcast journalism. He now is in demand as a knowledgeable and competent editor and event host and moderator, both for in-house events and ones for the public.