ABSTRACT
Propelled by a giant caudal (tail) fin, the whale shark (Figure 7.1) that can grow 12 meters in length, comes up from depth to feed on plankton, cruising slowly, open mouthed, just beneath the surface. Although it can be much bigger than a noisy, propeller-driven, dive boat the shark is silent, creating no obvious wake in its path. When you see such a majestic creature you cannot help but wonder whether or not finned propulsion is superior to screw propulsion, used for all boats and submarines.
