Reducing the barnacle bill

Scientists at the University of Wisconsin-Madison have developed a marine ‘electric fence’ to discourage molluscs from attaching to the hulls of ships, a problem known as biofouling,

The researchers report promising results from early tests of their system, which shoots tiny electric jolts through the underside of a boat. In preliminary experiments, the current reduced the accumulation of marine life by up to 50 per cent.

‘It’s unlikely we would be able to prevent biofouling entirely due to the enormous diversity of fauna in the seas,’ said Rodolfo Perez, a UW-Madison doctoral candidate of civil and environmental engineering. ‘But even reducing the hull-cleaning cycle by just a bit would be a huge, tremendous advance.’

Biofouling can cause drag, meaning ships could require up to 30 per cent more fuel. Ecological problems can also result from foreign species being introduced into unfamiliar waters.

The UW-Madison researchers plan to coat the hulls of boats with thousands of microscopic titanium electrodes between 8 to 25 microns apart that would gently zap any organisms that come near.

In small-scale tests, Perez evaluated the anti-fouling power of the electrodes and confirmed the potential of the UW-Madison concept. Future challenges include learning why the system works and determining how to produce a ‘blanket’ of electrodes that would cover and adhere to a boat’s entire hull.