THE BIOFOULING ISSUE

AQUATIC INVASIVE SPECIES

Fouled hulls are further known to act as vehicles of transportation for invasive aquatic species, which have proven to have negative effects on marine eco-systems. The issue is being adressed regionally and through IMO, resulting in possible hull inspections prior to making port calls.

BIOFOULING

The variety among biofouling organisms is highly diverse and extends far beyond attachment of barnacles and seaweeds. According to some estimates, over 1,700 species comprising over 4,000 organisms are responsible for biofouling which occurs in all oceans around the globe. Biofouling is divided into micro fouling – biofilm formation and bacterial adhesion, and macro fouling – attachment of larger organisms.

FOULING PRESSURE

Although marine biofouling occurs in all oceans, the fouling risk is different in different areas. In general, tropical or sub-tropical waters are considered high risk areas with rapid growth and settlement of organisms. With average global water temperatures increasing, high risk fouling is expanding, covering larger areas. Idling in these regions is therefore associated with large penalties as regards fuel consumption and maintenance costs.

Seaborne trade has been a large part of domestic an international trade since a few hundred years BC. Ever since, the fouling of ships’ hulls has troubled mankind and from time to time heavily impacted the use of ships in oceanic waters.

There is evidence from 412BC that various efforts were made to free hulls from excessive drag associated with marine fouling. The tremendous impact of heavy fouling on ship hulls have throughout the years resulted in a large amount approaches to combat the problem once and for all and after more than 2500years the industry concludes there is still room for improvements.  

The existing fleet is estimated to consume 350 million tonnes of fuel per year, emitting 1.1 billion tons of CO2 and over 10 million tons of SO2. If leaving hulls unprotected, the fuel consumption would increase by more than 40% on average on the world fleet due to the sharp increase in surface roughness caused by marine fouling. Yet, it is commonly believed that there is a potential to improve another 10% on average driving development of new, more efficient and environmentally sound coatings. If successful, approximately 30BUSD may be taken out from the operating costs of the world fleet, not to mention the emissions to air and the reduced risk of carrying invasive aquatic species hidden on a fouled hull.

THE CHALLENGE IS INCREASING

Considering existing trends on IMO regulations and guidelines related to emissions to air (MARPOL Annex VI) , invasive aquatic species (IMO resolution, MEPC.207(62)),  and efficiency measures (EEDI, SEEMP), the importance of a clean hull, no matter what conditions, will be of greater importance.

It is widely recognised that tropical and subtropical waters are considered as high risk areas from an marine fouling perspective. Since the 1990s, the trade patterns have shifted and a dominating portion of seaborne trade is frequenting ports located in such waters (UNCTAD).

Consequently, the need and challenge to improve hull performance remains high and needs to be responded to by innovative and more powerful coating systems.

ANTIFOULING COATINGS

Marine fouling is controlled by applying coatings/paint to the ship hull. The vast majority of coatings rely on active ingredients, so called biocides, acting either through a toxic mode of action or through a more specific repellent mode of action (Selektope®).

Approximately 150 million litres of antifouling coatings are being produced each year and supplied worldwide. The majority is sold to the commercial shipping community while smaller portions are used for leisure crafts, peace keeping vessels (navy) and other marine installations.

Throughout the years all sorts of attempts have been made with various results. Since the ban on TBT, new rigorous regulations have been put into force regarding the use of marine biocides. In near future, less than 10 active agents are expected to be available to the industry, reduced from >18 back in early 2000’s.

These active agents are being expected to control most of the 1700 species being part of marine biofouling. Out of the 1700 species, the barnacles are considered the “public enemy number one” due to its severe effects on drag (more than 40% increase in drag at small to medium hull coverage).

With the break through of the novel Selektope technology a new tool is provided to the industry deliver state of the art anti-barnacle performance while leaving room for technology to respond to exsiting and future demands for all vessels and all applications.

FIND OUT MORE ABOUT SELEKTOPE HERE