The human eye relies on an air-filled space in front of the eye for a clear vision. A diving mask creates a limited airspace in front of the face, which allows you to see clearly under water.
Before your first dive
Before the dive the mask has to be prepared against fogging. The cheapest defogging agent is your own saliva. Spit so courageously into your mask, rub the glasses with it and rinse it with water. Important, soon as you take off your mask or put it amateur like on your fore head, you have to defog again.
When putting on the mask, make sure you don't have any hair or part of a hood trapped under the mask seal. If you do, your mask will leak. The mask has to sit firm but not tight on your face. If you pull the mask strap to tight, the mask seal might turn and leak again.
Since the mask is building an air filled space in front of your face, it needs to be equalized on descend. It is easily done by exhaling through your nose.
Basic knowledge for Open Water Diver* (OWD*)
A diving mask consists of the following components:
- Glasses: They are ideally made of tempered glass. If necessary, they can be replaced by optical glasses.
- Nose pocket: It is important to be able to equalize and to clear the mask from water.
- Lip seals: They make contact with the face and seal the mask against penetrating water.
- Mask strap: It holds the mask on the head. Especially with long hair, it can be very useful to pull a protector made of neoprene over the mask strap.
- Mask body: It is the intermediate piece of silicone between the sealing lips and the mask frame.
- Mask frame: Keeping everything together and holds the glasses in place.
A diving mask is a very personal piece of equipment that every diver should own. When buying, make sure that the mask sits comfortably. Most important, check if the mask fits in respect of water tightness. Hold the mask against your face, breath in through your nose, if the mask get sucked slightly to your face and holds while you are holding the breath and without supporting it with your hands, it is most likely watertight while diving.
Fog forms in a mask because your body heat warms up the air in the mask, allowing moister to condense on the cooler glass. By spitting in before the dive, a thin film of grease forms on the glass, on which no more moister can condense. If you sweat heavily on the way to the water, especially at high temperatures, it helps to cool the face for a few seconds in the water before putting on the mask.
For new masks, this effect is even more imperative cause manufacturers conserve the masks for storage with some silicon oil, which makes it impossible do defog your mask. To prepare your mask for the first dive you can:
- Brush the glasses with toothpaste on the inside, let it dry and clean them with a soft cloth. Maybe you have to repeat that several times.
- Using an anti-fogging agent from your dive shop. Please always refer to manufacturers recommendations.
Even with well-fitting masks, it can not be avoided that water penetrates into the mask. This is an almost normal process during diving and should not disturb, influence or even panic you. The water can be removed very easily by the so-called mask clearing.
Here you press the upper mask frame slightly with your hand against your face, put your head back and breathe out through your nose, like you would blow your nose. The exhaled air rises up in the mask, builds up some overpressure in the mask which forces the water down and out of the mask. You should master this exercise in your sleep, because flooding your mask under water can happen at any time and for various reasons. If you haven't been diving for a while a responsible dive center might ask you to demonstrate this exercise on a check dive.
The mask should be rinsed with fresh water after the dive and kept in a shady place to dry.
If there is a black mold on the inside of the mask, treat the mask with a commercially available mildew remover and rinse afterwards thoroughly. On black mask bodies, a mold is barely visible, but still present.