Free diving is the most common and oldest form of diving. In the past it was a means of obtaining food, shellfish, or discovering sunken objects.
The basics have not changed much through the ages; a deep breath at the surface and down you go. When your air runs out, you resurface for a new breath. In order to enjoy marine life below the surface, all you need is a mask. Additions include fins for easier propulsion and a snorkel for breathing at the surface. In colder waters, or for extended stays, a neoprene suit is advisable.
As the quantity of oxygen in the body is limited, here are a few useful tips on how to extend submersion:
- before diving, spend a couple of minutes relaxing all muscles (best done by floating on your stomach) to enrich the bloodstream with oxygen
- expel air from the lungs and inhale new air deeply to fill lungs to full capacity
- to avoid oxygen and energy consumption use your hands instead of fins initially at the surface
- arms should subsequently be kept along the side of your body to provide as little water resistance as possible
- fin technique, as all other movements underwater, is also important and should be relaxed
- on surfacing, air may also be expelled through the nose (to level out pressure in the mask and environment) while excess air runs out through the mask in the form of bubbles.
Apart from recreational diving, there are two other types of diving – competitive free diving and spear hunting. Aside from basic equipment (mask, snorkel, fins), additional specific equipment is used, e.g. monofins, full neoprene suits, spear guns, etc. A prerequisite for these activities is good psycho-physical training and more detailed knowledge of the physiology of free diving, specific dangers and first aid.
Although it may seem simple, free diving is a potentially dangerous sport. One of the dangers is forced breathing (hyperventilation of the lungs) before a dive as it may give the diver the illusion of being able to stay underwater for a longer period of time. This is most often the cause of drowning among divers because the diver is unable to reach the surface and looses consciousness due to oxygen deficiency.
For your own safety, free diving should always be done in pairs. While one of the pair is underwater, the other keeps watch until he reaches the safety of the surface. In order to be visible to boat traffic, divers should display a signal flag indicating that there are divers in the water.