Most of us know swimming as an activity you try to make the most of. The ratio of exertion to effect is lower and more limited than we experience in most of our actions. This is due to the fact that our bodies have not evolved towards an aquatic existence. We lack the build to deal efficiently with the resistance of water. Most experienced swimmers have felt the thrust that flippers can provide.
The monofin is more than one step further. The balance of alternating thrusts of flippers is shifted from the symmetry between left and right to the more complex relation between the propulsion of the monofin and the glidingpath. The relation between thrust and trajectory is basically one of power and balance. In the 'WaterWing' these are wed: by tilting the wing and either heaving it up or pushing it down efficient and effective propulsion is produced, while simultaniously vertical steering is rendered by its plane-like properties. The frontal resistance of the 'WaterWing' is minimal, while the resistance of the flat surfaces are variabel by inclination. Horizontal steering is not specifically related to propulsion and therefore a topic in manoeuvring.
The balance between the monofin and the 'WaterWing' is one of arching symmetry: when the monofin is moved downwards, the 'WaterWing ' also moves down. Same for upwards. Isolated from actual movement, the 'WaterWing' acts as a push-off plane for the monofin. Also, and simultaneously, the monofin acts as a push-off plane for the 'WaterWing'. This double push-off increases the exercise of physical power. The joint effect of efficient and powerful propulsion makes it possible to move with the firmness of the water. It provides a level of control that is far greater than the effect ratio in common swimming. Because every labour stroke is at the same time a recovery stroke for the next labour stroke, there is very little interruption in flow.
The result is an undulating trajectory that is very well suited for underwater travelling. Speed, in this respect, is a relative option. A trained swimmer can obtain high speeds, but this also takes a lot of breath, which is normally not available under water. A snorkel is a partial solution, a diving tank (minus it's water resistance and deco-hazard) even more so. Diving time can also be made more effective by special manoeuvres. There are ways to scoop to five metres down in just a few seconds as there are for a swift escape for air, leaving more time to be spent on actual diving. Also there are ways to turn at the surface or under water and lots of turns and adaptions to react to the playful movement of a dolphin.
The latest addition to this instrumentarium is the dorsal fin. It is definitely helpful in submerging as it leads the drag of the vortex away from the body. Provisional research suggests that it layers the flow to facilitate passage.
Dolphins seem to recognise the movement and are known to investigate. Friendly, wild dolphins, like Irish-dwelling Fungi and Mara just love it.