THE DIVE

oBuoyancy and Position: Being able to control your buoyancy in cavern diving is very important. Be familiar with your BCD and try to use your lungs to manage your buoyancy. The depths change regularly during the dive so anticipate this and compensate your buoyancy accordingly. Remember that the cavern environment is very old and very fragile. Always try to maintain a horizontal position in the water. In the above picture, this cave diver is in a very good horizontal position. His knees are bent at a 90˚ angle, allowing him to do the frog-kick much easier. This will make sure that you do not stir up any sediment from the floor of the cavern and also that you do not hit your head on the ceiling!

oFinning: In cavern diving you cannot use the same finning techniques that you use in the ocean. It is important not to stir up sediment and cause bad visibility. Use the frog-kick or the modified flutter kick, which will be demonstrated by your guide.

oLines: The permanent cavern line is put in place for your safety. Respect it by staying within one arm length from the line. It is very important to always stay above the line and NEVER pass underneath it. You can easily become entangled, causing panic and potential damage to your gear, the line line and also the cavern.

oHalocline: The halocline is the part where fresh and salt water meets. On many, but not all dives, you will encounter a halocline. Salt water is much heavier so it lies below the freshwater. Haloclines create amazing visual effects when light passes through it; however, when these two waters mix it reduces visibility. Your guide will indicate that you change to a side-by-side configuration (where possible) in order to maintain visibility. When you pass to the salt-water section of the halocline your buoyancy will need adjusting because salt water is denser than fresh water.

oOther groups: You will discover then cenote diving is very popular! It may become disorientating when diving with many other groups of divers entering the cenote and following the same line throughout the dive. Stay with your group and familiarize yourself with your guide and the other divers in your groups. For example, the color of the fins, wetsuit or any other distinguishing characteristics.

oAir (gas management): We use the rule of thirds in cavern diving and thus must know beforehand when to signal the guide. We simply take the full tank and divide ti by three (3). So if you are using an SPG that measure your gas pressure in BAR, you will have a full tank at 200 BAR. We generally divide it into three parts of 70 BAR, therefore,

                1/3 = 70 BAR            2/3 = 140 BAR         3/3 = 200 BAR (full tank)

    If you are using an SPG measuring your gas pressure in PSI then your full tank will be 3000 PSI. This is easy as you simply divide it into three parts of 1000 PSI. For example:

                1/3 = 1000 PSI         2/3 = 2000 PSI         3/3 = 3000 PSI (full tank)