ABSTRACT
Despite the use of thrust augmenting swim fins, a diver’s top speed is only about 1 m/s [1], dangerously slow when compared with some tidal currents that can exceed 3 m/s and very slow compared with marine mammals such as the bottlenose dolphin that can swim at up to 6 m/s [2]. It is drag that slows the diver; but we can use it to our advantage: drift diving or traveling with a current can be an exhilarating underwater experience, as one passes rapidly over scenery and gets turned this way and that way in swirling eddies. If a current is faster than 1 m/s, the diver is virtually powerless against it. This can be frightening and dangerous if you are being carried away from boat or shore. One cannot eliminate drag but it should be possible to reduce it and be in control. To find a way to do this we can consider the factors that influence drag production.
