From John Coombe-Tennant
I found your article on reducing drag by pumping a layer of air between a ship’s hull and the water stimulating (18 February, p 46). Presumably this technique might also reduce the amount of fouling from barnacles and seaweed which a hull attracts, further improving its streamlining and enabling ship owners to use less anti-fouling paint. In this way chemical pollution might be reduced, but perhaps at the expense of increased underwater noise pollution, with the “bubble” ship giving off high-pitched hissing and whistling noises to the discomfort of whales.
If a new organic surfactant could be developed from some kind of seaweed or lichen, it might be possible to reduce the turbulence in the boundary layer and help hold the bubble envelope in place around the hull. This would be preferable to pumping slippery polymers out of the hull into the water: I don’t like the idea of a supertanker leaving a trail like a snail.
London, UK
