Banishing barnacles

The barnacle’s love affair with the hulls of boats is under threat from a new type of ‘antifouling coating’ based on a dolphin’s skin.

Boats and barnacles: forever bound together in briny bridal bliss.

But the hardy crustacean’s love affair with hulls is under threat from a young pretender; a new type of ‘antifouling coating’ based on a dolphin’s skin.

Barnacles and other tiny marine organisms pose a number of problems for all kinds of shipping. The gluey adhesive they secrete leads to metal corrosion, and, if enough of them attach to the hull, friction and drag can seriously affect fuel efficiency.

While tin or copper-based coatings have been used with moderate success for some time, fear over chemicals leaching into the water has led the UN to call for a worldwide ban on these coatings by 2003.

Boat designers have also long thought that marine fouling can be discouraged by making hull surfaces as smooth as possible. This belief is called into question by research carried out at Washington University in St Louis.

Professor Karen Wooley, of the University’s chemistry department, is developing a group of nontoxic coatings based on the shape and texture of dolphin skin.

Using electron microscopy, Wooley’s teams has found that dolphin skin, despite its apparent smoothness, is slightly rippled on the nanometre scale.

While these ripples are not large enough to hinder movement through the water, the complex surface makes it difficult for marine organisms to get a grip.

It is believed that the new coating could be on the market before the UN ban comes into force in 2003.