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Scientists have developed a novel way to combat one of the world's stickiest and most expensive maritime problems: the encrusting of ships' hulls by algae and barnacles.
They have created a special coating, using nanotechnology, that is engineered to a scale of a millionth of a millimetre. Organisms that try to hitch a ride will simply slip off.
The development, announced at the EuroNanoForum in Dusseldorf last week, is important because "bio-fouling" costs billions of dollars a year, not just to the shipping industry but to private yachtsmen and owners of power and desalination plants whose pipes get blocked by bacteria and barnacles.
In addition, ships burn excess fuel with encrusted hulls, increasing carbon emissions; while current anti-fouling paints are thought to harm sealife.
"We badly need a new anti-fouling agent and nanotechnology will provide it," said Frederic Luizi, research director of Nanocyl, a member of the European consortium Ambio.
Algae and barnacles have always been maritime scourges.
The Greeks used pitch to discourage them while the Romans found copper nails released poisons that helped kill them. Yet the problem has remained a major headache.
Once a ship is encrusted, its speed can be reduced by up to 10 per cent, while fuel consumption rises by 40 per cent. The world's shipping fleets spend more than US$10 billion ($13 billion) on the problem annually.
Biocidal paints - which poison anything that adheres to a surface - are often used. But 20 years ago scientists discovered that tributyltin, a key agent, was poisoning marine organisms and triggering sex reversals in creatures such as the dog whelk. Now it is banned.
Instead, copper-based compounds are used though fears are mounting about their impact and restrictions may soon be introduced.
By incorporating carbon nanotubes, tiny cylinders of carbon, each a thousand times thinner than a human hair, into paints, scientists have created a material that stops organisms sticking to hulls. When the ship moves, the organisms are swept away.
- Observer
