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NEW TECHNICAL DIVING COURSES
www.n-techdivertraining.co.uk
The TDI Intro to Tech course is the perfect course for divers who have heard about technical diving and want to find out more about this exciting branch of advanced recreational diving. This course walks students through the special techniques, planning procedures and skills that set technical diving apart from traditional sport diving. It will show them how to improve their dive planning methods, in-water skills and streamline their existing gear configuration, in a non-threatening and fun learning environment. The specific skills this course will highlight are:
- Advanced Buoyancy Control
- Gas Management
- Situational Awareness
- Trim
- Gear Configuration and Selection
- Many More!
TDI’s Intro to Tech course is a useful stand-alone course for the diver who wants to become a more skilled, more proficient diver regardless of if he intends to move on to technical diving. The course may also be used as an introduction to the TDI Advanced Nitrox course and the TDI Decompression Procedures course. And finally, it is also a good refresher for certified technical divers who may want to refresh their skills or have them re-evaluated by a TDI technical instructor.
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The TDI Advanced Nitrox Course qualifies divers to use enriched air nitrox from EAN 21 through EAN 100 to a depth of 40 metres/130 feet during dives hat do not require staged decompression. Often taught in conjunction with the TDI Decompression Procedures course, this can be considered the foundation of your technical diving career. Advanced Nitrox is also a great course for those wanting to extend their bottom times in shallower depths such as scientific diver, and a must for SCR or CCR divers. The course cover topics like
- Equipment requirements ive planning
- Oxygen tracking
Blending methods
You will use the TDI Advanced Nitrox Diving manual for your course, which explains in an
easy to understand practical manner the complex information that Advanced Nitrox divers need to know.
Decompression Procedures Diver
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As sport divers planned decompression is not something that we do or have been taught. The TDI Decompression Procedures course prepares you for planned staged decompression diving. With a maximum operating depth of 45m/150 feet, this course is your first step beyond the normal sport diving limits. Your TDI Instructor will provide you with valuable information and skills, among the topics covered are
- Kit set-up
- Equipment requirements
- Decompression techniques
- Decompression breathing gases
- Gas management
- Contingency planning
The TDI Decompressions Procedures course combined with the TDI Advanced Nitrox course form the foundation of all other technical courses. After these two courses and some additional experience, the stage has been set for you to move onto additional technical levels. Some of the materials you will be using include the TDI Divers Guide to Decompression Procedures, US Navy or Buhlmann Air Decompression Tables (made of vinyl for easy in-water use and storage)
A range of closed circuit/rebreather courses are also available.
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For further information about each course and prices please contact:
Neil Holden: 07817854199
neilholden2@sky.com
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Del Mar has a number of technical divers within the branch, both with the more traditional open circuit qualifications, but there is also a growing number of rebreather divers. We are one of the very few BSAC branches that actively take part in technical diving trips with a number of members qualified to Advanced trimix level (100m) in open circuit and closed circuit. Below gives you an idea of what technical diving is all about.
Technical diving is a form of scuba diving that exceeds the scope of recreational diving. Technical divers require advanced training, extensive experience, and specialised equipment and often breathe breathing gases other than air or standard nitrox. Technical diving may include all or some of the elements below :
DEPTH
Technical divers may be defined as being either dives to deeper than 40 metres or dives in an overhead environment with no direct access to the surface or natural light. Such environments may include fresh and saltwater caves and the interior of shipwrecks. In many cases, technical dives also include planned decompression carried out over a number of stages during a controlled ascent to the surface at the end of the dive.
The depth-based definition is derived from the fact that breathing regular air while experiencing pressures, causes a progressively increasing amount of impairment due to nitrogen narcosis that normally becomes serious at depths of 30 metres or more. Increasing pressure at depth also increases the risk of oxygen toxicity based on the partial pressure of oxygen in the breathing mixture. For this reason technical diving often includes the use of breathing mixtures other than air.
INABILITY TO ASCEND DIRECTLY
Technical dives may alternatively be defined as dives where the diver cannot safely ascend directly to the surface either due to a mandatory decompression stop or a physical ceiling. This form of diving implies a much larger reliance on redundant equipment and training since the diver must stay underwater until it is safe to ascend or the diver has left the overhead environment.
DECOMPRESSION STOPS
A diver at the end of a long or deep dive may need to do decompression stops to avoid decompression injury. Inert gases in the diver's beathing gas, such as nitrogen and helium, are absorbed into body tissues when breathed under high pressure during the dive. These dissolved gases must slowly be released from body tissues by pausing or 'doing stops' at various depths during the ascent to the surface. In recent years most technical divers have geatly increased the depth of the first stops, so as to reduce the risk of bubble formation before the (more traditional) long shallow stops. Most technical divers breathe enriched oxygen breathing gas mixtures such as nitrox during the beginning and ending portion of the dive. To avoid nitrogen narcosis while at maximum depth it is common to use trimix which adds a percentage of helium replacing nitrogen to the diver's breathing mixture. High nitrox mixes or pure oxygen is then used during shallow decompression stops to reduce the time needed by the diver to effectively rid themselves most of remaining excess inert gas in their body tissues and reducing the risk of an injury. Surface intervals are usually required to prevent the residual nitrogen from building up to dangerous levels on subsequent dives.
GAS MIXES
Technical dives may also be defined by the use of hypoxic breathing gas mixtures other than air such as, trimix, heliox and helair. This definition is derived from the fact that beathing a mixture with the same oxygen concentration as is found in air (roughly 21%) at depths greater than 55 metres results in a very rapidly increasing risk of severe symptons of oxygen toxicity. Increasing pressure due to depth also causes nitrogen to become narcotic, resulting ina 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 buildup 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 courses throughout the yearlimit of Nitrox is governed by the percentage of oxygen used, as there are multiple oxygen percentages availabl 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. Delmar runs a number of BSAC Nitrox courses throughout the year.
EQUIPMENT
Technical divers may also use various forms of less common diving equipment to accomplish their goals as the dives involve significantly longer durations than average recreational scuba divers. As decompression stops act as a virtual overhead, preventing a diver with problems from surfacing immediately, there is a need for redundant equipment. Technical divers therefore increase their supply of available breathing gas by either connecting multiple high capacity diving cylinders and/or by using a rebreather. The technical diver may also carry additional cylinders, known as stage bottles, to ensure adequate breathing gas supply for decompression with a reserve for bail-out in case of failure of their primary breathing gas.
WHAT IS NITROX ?
Air contains 21% oxygen and 79% nitrogen. Enriched Air Nitrox (EANx) is the result of increasing the oxygen content of the mixture, with a corresponding decrease in the content of nitrogen. The description EANx is followed by an indication of the oxygen percentage of the mixture, so air could be described as EANx 21. A mixture containing 32% oxygen is EANx 32, and the description EANx 36 would indicate that the oxygen content was 36%....simple.
Each gas mixture has a maximum safe depth limit determined by its partial pressure of oxygen.
Nitrox is NOT a deep diving gas.
There are many advantages of using nitrox, two of the main ones are …
Greater safety margin against the risk of decompression injury….
Or
If nitrox tables or a nitrox computer is used, then longer no-stop dive times can be planned…..
Disadvantages…?
Yes there are some, they include…..
Calculations and dive planning need to be more thorough
Oxygen toxicity
Gas mixing and analysing
Dedicated diving equipment
BUT the advantages certainly out weigh the disadvantages. But like everything, to use nitrox in a safe way you must undergo proper training with a recognised training agency…..Get in touch if you want more information on Nitrox courses.
