What is Tec Diving?
Technical diving, commonly referred to as Tec diving, is a form of scuba diving that exceeds the scope of
recreational diving (although the vast majority of technical divers dive for recreation and nothing else).
Technical divers require advanced training, extensive experience, specialized equipment and often
breathe breathing gases other than air or standard nitrox.
Nitrox, Trimix, Normoxic?
Technical dives may also be defined by the use of hypoxic breathing gas mixtures other than air such as
trimix, heliox, and heliair. This definition is derived from the fact that breathing a mixture with the same
oxygen concentration as is found in air (roughly 21%) at depths greater than about 55m results in a very
rapidly increasing risk of severe symptoms of oxygen toxicity. The first sign of oxygen toxicity is usually a
convulsion without warning. This convulsion usually results in a fatal accident, as the regulator falls out
and the victim drowns. Sometimes the victim may get warning symptoms prior to the convulsion. These
can include visual and auditory hallucinations, nausea, twitching (especially in the face and hands),
irritability and mood swings and dizziness. Increasing pressure due to depth also causes nitrogen to
become narcotic, resulting in a reduced ability to react or think clearly. By adding helium to the breathing
mix, divers can reduce these effects, as helium does not have the same narcotic properties at depth.
These gas mixes can also lower the level of oxygen in the mix to reduce the danger of oxygen toxicity.
Once the oxygen is reduced below 18% the mix is known as a hypoxic mix as it doesn't contain enough
oxygen to be used safely at the surface.
Nitrox is another common gas mix, and while it is not used for deep diving, it decreases the build up of
nitrogen within the diver's body by increasing the percentage of oxygen. This reduces the nitrogen
percentage, as well as allowing for a greater number of multiple dives vs "standard" air. The depth limit
of Nitrox is governed by the percentage of oxygen used, as there are multiple oxygen percentages
available in nitrox. Further training and knowledge is required in order to safely use and understand the
effects of these gases on the body in a diving situation.
Where do I start?
PADI Tec 40 Course
PADI Tec 40 Course
What is cave diving?
Cave diving is a type of technical diving in which specialized SCUBA equipment is used to enable the exploration
of natural or artificial caves which are at least partially filled with water. It is an extension of the more common
sport of caving, but is much more rarely practised because of the skills and equipment required, and because of
the high potential risks.
Despite these risks, water-filled caves attract cavers and speleologists due to their often unexplored nature, and
present divers with a technical diving challenge. Caves often have a wide range of unique physical features, such
as stalactites and stalagmites, and can contain unique flora and fauna not found elsewhere.
Hazards of cave diving
Cave diving is one of the most challenging and potentially dangerous kinds of diving and presents many diving
hazards. Cave diving is a form of penetration diving, meaning that in an emergency a diver cannot ascend directly
to the surface due to the cave's ceilings, and instead may have to swim horizontally. The underwater navigation
through the cave system may be difficult and exit routes may be at considerable distance, requiring the diver to
have sufficient breathing gas to make the journey. The dive may also be deep, resulting in potential deep diving
risks.
Visibility can be low, or non-existent. While a less-intensive kind of diving called cavern diving does not take
divers beyond the outermost part of the cave reached by natural light, true cave diving can involve penetrations
of many hundreds of metres, well beyond the reach of sunlight. The level of darkness experienced creates an
environment impossible to see in without an artificial form of light. Caves often contain sand, mud, clay, silt, or
other sediment that can further reduce underwater visibility in seconds when stirred up.
Caves can carry strong water currents. Most caves emerge on the surface as either springs or siphons. Springs have out flowing currents, where water is coming up out of the Earth and flowing out across the land's surface. Siphons have in-flowing currents where, for example, an above-ground river is going underground. Some caves are complex and have some tunnels with out-flowing currents, and other tunnels with in-flowing currents. If currents are not properly managed, they can cause serious problems for the diver.
Cave diving is perceived as one of the more dangerous sports in the world. This perception is arguable because the vast majority of divers who have lost their lives in caves have either not undergone specialized training or have had inadequate equipment for the environment. Many cave divers have suggested that cave diving is in fact statistically much safer than recreational diving due to the much larger barriers imposed by experience, training, and equipment cost.
Cave diver training
Cave diving training includes equipment selection and configuration, guideline protocols and techniques, gas management protocols, communication techniques, propulsion techniques, emergency management protocols, and psychological education. As cave diver training stresses the importance of safety it does point out cave conservation ethics as well. Most training programs contain various stages of certification and education.
Cavern training explains the basic skills needed to enter into the overhead environment. Training will generally consist of gas planning, propulsion techniques needed to deal with the silty environments in many caves, reel and handling, and communication.
Where do I start?
CDAA Deep Cavern Course
CDAA Deep Cavern Course
