This is the second part of my Free Diving Blog. Part One covered the basic introduction to free diving; in Part Two I want to get into more details about this fast growing sport.
Part Two covers the effects of pressure on our body and how we can equalise airspaces to avoid the discomfort this causes.
We will also be having a look at the basic equipment needed for free diving; mask, snorkel and flippers/fins plus a couple of optional extras.
AquaLung Express Fin designed with the sleek lines of a snorkeling fin.
Water Pressure and Equalising
Water pressure increases with depth; if we were to dive straight down we would experience a slight discomfort in our ears.
From 6 meters this pain would become unbearable and continuing deeper would cause our eardrums to eventually burst. To overcome this problem, we equalize the pressure from within the ears, in turn keeping our eardrums in their correct shape and avoiding further problems.
Equalising the Ears
There are a few different equalizing techniques that a person can use, but we must remember that what works for one individual may not work for another. The most common technique is simply pinching the nose with the thumb and fore finger. As you descend, clasp your nose and blow very gently; this should cause the ears to click and the pressure should be immediately relieved. Some divers are fortunate in that they can equalize by simulating a yawn, others swallow or merely rotate the jaw. This you may only learn through experience.
If your ears are not equalizing easily under normal circumstances, you may need a medical check up before attempting to dive again. Likewise, It is not advisable to dive when suffering from a cough, cold, influenza or any such complaint that produces an excess of mucus in the head, as this makes equalizing difficult and can easily do your ears and sinuses a lot of harm. Ear plugs should also never be used when diving.
Equalising the Mask
As you descend when diving, you will find that in addition to the pressure build up in your ear drums, your mask will also begin to press against your face and cause a certain amount of discomfort. This is because of the dead air spaces in the mask, that compress when the surrounding pressure increases. To overcome this, simply blow a few ‘puffs’ of air into the mask through your nose as you desend.
Choosing your Equipment
An important aspect of diving is finding the right equipment for the type of diving you choose to participate in and what will individually suit you.
The mask is by far the most important item of equipment in any divers kit bag. It enables the diver to see underwater.
Your mask must become a part of you; you should never feel physically conscious of it.
Choosing a mask is pretty simple. Test the seal against leaks by holding the mask in position and breathing in through your nose, drawing the air out of the mask until it is pressed firmly against your face. Hold your breath; the mask should now stay in position on its own. If it falls off it is not sealing properly and is not suitable for you.
The snorkel enables you to breathe normally while on the surface without the need to lift your head out the water.
This means you can maintain a constant, uninterrupted watch below the surface. The most important aspect of choosing a snorkel is that the mouth piece must feel completely comfortable and breathing must be as free as possible. The length and material of the tube can be dependant on conditions. For example; a diver on the surface with choppy seas may choose to have a longer tube with a splash guard to prevent water entering, or a diver diving in kelp or weed may choose a tube with flexible material so it does not become entangled.
Fins are designed to increase the thrust of the legs when swimming, enabling a diver to swim comfortably using the legs only. It is totally up to the individual what design, length and material these fins are and there are many to choose from. When choosing fins, it it important that the shoe fits as well as possible without being too tight or loose. If too tight they can cause leg cramp, and if too loose the can easily be ripped off in heavy surf. Some Free Divers even choose to dive with scuba diving fins as they provide more power.
Depending on the conditions in which you are Free Diving, you may decide that the water is too cold to enter without any means of insulation. A wetsuit is used to enable a diver to remain in colder waters with a reasonable degree of comfort and for longer periods of time far in excess of anything that is possible in normal swimming gear. The majority of wetsuits are manufactured from neoprene which, as well as trapping a insulating layer of water, also provides reasonable protection against things like jelly fish, barnacles and sharp rocks. In choosing a wetsuit, the main consideration is comfort; It must fit as well as possible without being too tight. The thickness of the wetsuit should be chosen to suit yourself and the water temperature.
Neoprene is a buoyant material, therefore if you are planning to dive wearing one you will need to consider wearing a weight belt. A weight belt is used to counteract the buoyancy of a wetsuit. It is important with choosing weights that you are neither over or under-weighted. You must, however, be positively buoyant, i.e. if you lay on the surface with a weight belt on and completely exhale the air in your lungs you should continue to float. A rough guide when choosing how many weights you need is one kilogram of weight to every ten kilograms of your body weight.
When Free Diving, many divers choose to carry a knife with them. It is far from uncommon to be entangled in fishing line or net, which would be fatal if you had no means of freeing yourself before the urge to breathe kicked in. Be sure to choose a knife with a fine cutting edge, and always wear your knife in the same position to avoid fumbling for it in an emergency.
It is helpful to choose a knife with a quick release system and secure storage – it is not uncommon to loose a knife while diving.
Preparing to Dive
Now that I have covered equipment, it is time to talk about preparation before diving; by this, I mean preparation on the surface. The length of time you spend underwater is governed directly by the manner in which you prepare yourself for the dive. This topic will be covered in the following blog.
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