1. How do I get started in Technical Diving ?
Without a doubt the safest and quickest safe way to start is via one of the specialised courses offered by the technical or air training agencies. This will be firstly via a basic Nitrox course leading on to deep air training and subsequently Trimix if you want to proceed that far.

2. How experienced do I need to be before undertaking technical diving training ?
Although the threshold of required experience has steadily been lowered over recent years , mainly for commercial reasons, you really have to have a sound knowledge of the basic principles of diving and a reasonable experience of diving under differing conditions which you are unlikely to have acquired with less than 100 open water dives to reasonable depths ( 30 mtrs.+).

3. What equipment will I need ?
Although most of the equipment owned by a sports diver can make the transition to technical diving , you will require to double up on essential items , masks , torches etc. In addition, because of the depth encountered, twin cylinders and a high capacity lift wing type of harness, to mount them on, will also be required. The capacity of the cylinders will depend on your ultimate goal, whether this be deep air or Trimix diving. In addition you will also require one or more side mounted cylinders for decompression gasses.

4. Will this equipment need to be especially prepared ?
Yes, all equipment that comes into contact with the air or gasses being used in technical diving needs to be cleaned to rid it of hydro carbons normally found in the compressed air . The equipment is then said to be in Oxygen Service and this will need to be repeated on an annual basis.

5. Should I manifold my cylinders or not ?
This is a hotly debated subject and there is no correct way. Both ways have their merits and pitfalls. By having a manifold linking the two cylinders together the diver has access to a large reservoir of air during his dive without the bother of having to swop over regulators halfway through the dive. As a precaution, an isolating tap can be incorporated into the manifold to isolate one cylinder from the other in case an o ring gives way so that only the air from the damaged cylinder is lost , leaving the other available to the diver.

By not fitting a manifold the diver has to gauge the air in each cylinder and will probably have to change cylinders during the dive, needing to swop regulators underwater. If you are comfortable with this technique , this is the safest option because, in effect, you are diving with two totally separate, complete systems which can be utilised in case of the failure of one . It is a matter of personal taste and judgement based on what your Instructor teaches you and what you are most comfortable with underwater .

6. What are side mounts or "slings"
These are cylinders which the diver will carried mounted onto his harness and carried on each side, in addition to his main set on his back. The purpose of which is to carry the gases used for decompression at the end of the dive. These are generally filled with oxygen rich mixtures to enable the diver not only to speed up the decompression but also to ensure the safe removal of traces of helium and and nitrogen from his body.

The sizes of these cylinders will vary according to the type of dive and the depth being reached . As a guideline , dives down to 60 / 65 mtrs. will require 7 Ltr. cylinders minimum and possibly 10 Ltrs. Depending on the duration of the dive at the deepest point. Beyond 65 mtrs. You should consider 10 Ltrs as the minimum requirement and 12 Ltrs a possibility , again depending on depth reached and the duration of the dive.

7. Where will I get the specialised gasses from and are there any special requirements ?
An increasing number of dive shops now stock Oxygen and Helium together with Argon , used for suit inflation. You will have to produce proof of training for the gas that you require . This will be the C card you obtain from your training agency when you qualify. In addition you will either be asked to analyse the mix yourself or witness the analysis of the gas by the operator and then sign the log to show that that you have the correct mix in your cylinder.

8. Are there any special requirements for handling the extended decompression times ?
Technical diving will impose lengthy deco. Stops so consideration must be given to the quality of the dry suit and undergarments. Choose 200 grams under suits if possible and for very long deco's you may well want to wear T shirts or other items underneath as well.

Also, there are the problems of getting rid of bodily fluids so some kind of "Pee valve" could well be built into the suit. Proper hydration before the dive is vital and this can lead to a very uncomfortable decompression period if due allowances are not made.

9. What decompression tables should I use ?
During your training course decompression should be covered in depth and the various hard and computer generated tables will be discussed. There are now several very good tables available that can be used through a PC so that the diver can "cut" his own tables to suit a particular dive and the conditions likely to be encountered. These tables will be very different from those familiar to the sport diver.

10. How can I gain suitable experience after completing my training courses ?
Without doubt , this is one of the most difficult aspects of technical diving , how to break into an established dive team where you can gain the experience you require. By their very nature these teams are there to dive and not to train, so this is often very difficult for the newly qualified technical diver. A good starting point is your Instructor and the other members of your training course. If you do not live too far apart you may consider diving together and slowly gaining experience. Otherwise your local boat skipper may be able to put you in touch with any groups that use his boat. Either way the key is to gain experience slowly and not dive beyond your capabilities.