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Ken: >>I've always wondered this; What exactly is an "Extended Range Diver"? I'm a bit surprised by your question Ken ;) Guy wrote: >TDI offer a training course with deep air to 60m (200ft), decompression diving and the use of high oxygen deco gasses. Whilst the usefullness of training courses depends on the instructor as well as the material, I would have to say that this was the most solid training course I have done. It is also a simpler 'route' through the maize of qualifications than many other agencies. This is a good answer. In fact, TDI used to call this course 'Technical Diver'. They soon decided to change the name to 'Extended Range Diver'. The best name could probably be 'Technical Deep Air', but another agency was using it. Extended Range should not mean only 'going deep on air'. It also means performing longer dives, under targetted conditions. For example, I consider to be an extended range exposure, a dive requiring 2h30 of decompression in 40F waters. It does not matter if the dive was done at 100 feet or 200 feet. Anyway, with a good instructor, the student should learn to perform decompression dives using deco mixes, and he should also be introduced to more complex dive scenarios. Ken: >> Why should I be impressed? Guy: >This depends on a number of factors. I suggest it would be safer for you to not be impressed. I guess the diver concerned was pleased at the achievement and thought he/she should share this joy. Why deny someone a little joy. I don't think anyone has to be impressed. Unless we have to be impressed when we see a 'full cave' diver or a 'dive master', or anything else. It simply demonstrate that if the person had a good instructor, he learned something about what we call 'technical diving'. Ken: >>I've seen people like Hal Watts offering courses in "Extended Range >>Diving", but always just assumed it was a clever ploy to seperate >>divers from their money in exchange for another badge, but could >>never prove that. Is this indeed the case? You're probrably right about what Hal Watts is doing. To me, it is a big non-sense to bring people from 100 feet to 240 feet in a week (extracting money at each 20 or 30 feet). It took me years to do that and I believe that this is the way to go. Another point, PSA training at Forthy Fattom Grotto, to my knowledge involves only what we call 'bounce dives' where people can say, 'I went down and I came back up'. This is more a kind of a dive tour than a dive exploration. However, I must admit that Hal knows quite a bit about deep air diving. Guy: >For me TDI made it simpler and cheaper to get the deep air/O2 deco certification than IANTD or ANDI. I prefer more content and less number of training courses. But I was doing deep air diving prior to doing the ERD course. It became necessary to get a card for it so my dive operator didn't have to worry about being sued if I gacked one day, and if we want people to buy dive boats and give us unprofitable gas fills we have to look after them too. >If you have a tri-mix certification then you are, of course, above all this and I suggest you save your $$ to buy your gas. Helium seems to be pretty cheap in the US. I know I pay more, but on many dives, this is beneficial. I find funny all the discussions around 'deep air'. I'm not even sure about 'how deep is deep'. To some people, it seems that 130 feet is deep while to others, that's 240 or 300. I remember that usefulness of gases used to be defined as follows: . Nitrox: 40 to 150 feet . Air: 0 to 40 feet and 130 to 220 feet . Trimix: 160 to many many feet I still believe that these ranges are very appropriate. Very often, people say that trimix is the only good choice. But let's not forget that nothing is perfect. When trimix is involved, that means: . a more strict dive schedule . more gas switch . more gas blends to be carried . increased task loading . reduced deco safety margin (compared to an air diver using nitrox and O2 as air during deco) . increased risk of error . dependance on experimental tables (which are more and more reliable BTW) In the range of 160 to 220 feet, I think that trimix and air compete against each other. Each dive team (or individual) may end up with different risk/cost/benefit analysis results. I believe that all of them may be right. Just to finish. I want to reaffirm that I am not supporting deep air diving. I believe it's Benneth who said 'beyond 180 feet on air, someone is useless' (or something like that). This could be true if an emergency occurs. As well, it is well known that people do not all handle narcosis the same way. I know a person who get consistently narked at 80 feet (and badly at 100-120 feet). Have a nice day! Michel Therrien
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