Ships, like any object moving in fluid, experience drag forces. ‘Skin friction’, the effect of viscosity, is one component, which can become as high as 70% of the total. The implication of this is that a large proportion of the power output from the ship’s propulsion system is wasted in overcoming this form of resistance. Traditional solutions involve painting on sharkskin-like coatings or injecting bubbles into the surrounding water.
Today’s invention attempts to significantly lessen the extent to which water rubbing on a ship’s hull holds it back.
The hulls of vessels (eg supertankers) would be fitted with a number of lightweight external, dish-shaped ‘shields’ (the two outer ellipses in the diagram). These would be mounted, half in the water and half out, on very well lubricated central axles down which air would be blown so that the gap between the hull and the inner side of each shield would remain filled with a film of air.
The normal propulsion of the craft (shown moving rightwards) would cause these shields, with lower halves adhering to the surrounding water, to be rotated as shown.
This would also have the effect of lessening the expense of cleaning off the various forms of fouling caused by marine crustations etc on rigid hulls.
