Rebreather World - View Single Post - Article from COMEX Scientific Director on rebreathers, decompression and Penny Glover

SFM · 24th May 2006, 09:33

PMR: Are these incidents related to the mixes per se?
BG: It’s hard to express an opinion for all the accidents, but in Penny Glover and her student’s case, neither the nature of the trimix nor the control are questioned. On the other hand, three sources can be at the origin of their fate.
A gear problem obviously, but it’s unlikely since the divers reached the 6m decompression stop. Even if the Navy is reluctant to adopt electronic rebreathers despite their advantages, we can dismiss this hypothesis.
The second cause could be a training issue. There’s a reason why at the National Professional Diving Institute, the training sessions are done by Navy instructors. Some training centers for amateurs are serious, some not so much. I think that to be on top in this domain, one has to get out of his amateur diver “bubble”. One needs to be confronted to other realities than leisure/hobby diving, like Anglo-Saxons use to say, because with a trimix rebreather we’re very far away from it… Penny Glover was considered a very accomplished diver. I’m still astonished by the parameters of her ultimate dive. 40 minutes at 80m constitutes a major error for such a competent individual, especially with a student. Those values have to be confirmed, but if they are then the initial reason for their demise has likely been established.

PMR: Meaning?
BG: This leads me naturally to the third possible cause of accidents, no doubt the most probable in the majority of the cases: the decompression procedure and profile. In theory and because it delivers a mix with variable PPO2, the electronic trimix rebreather optimizes the dive perfectly. Viewed like that this type of gear is the ultimate weapon. Paradoxically the problem resides in the amazing performances of these devices. Their autonomy is such that divers need decompression procedures that are not always mastered.

PMR: Do divers disrespect decompression procedures?
BG: In general no, except for incidents. At this level, one should consider that divers are technically capable of managing their ascent, speed and stops. The main problems stems from the tables that are used… As long as one stays within durations not exceeding 15 minutes at 80m there isn’t any problem. The MN-78 tables are perfectly adapted and they’re available in “Diving physiology and medicine” by B. Broussole published by Ellipses. Beyond those 15 minutes, it’s an entirely different matter….

24th May 2006, 09:33	#4 (permalink)
SFM New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: May 2006 Location: West Coast Posts: 11	Re: Article from COMEX Scientific Director on rebreathers, decompression and Penny Gl PMR: Are these incidents related to the mixes per se? BG: It’s hard to express an opinion for all the accidents, but in Penny Glover and her student’s case, neither the nature of the trimix nor the control are questioned. On the other hand, three sources can be at the origin of their fate. A gear problem obviously, but it’s unlikely since the divers reached the 6m decompression stop. Even if the Navy is reluctant to adopt electronic rebreathers despite their advantages, we can dismiss this hypothesis. The second cause could be a training issue. There’s a reason why at the National Professional Diving Institute, the training sessions are done by Navy instructors. Some training centers for amateurs are serious, some not so much. I think that to be on top in this domain, one has to get out of his amateur diver “bubble”. One needs to be confronted to other realities than leisure/hobby diving, like Anglo-Saxons use to say, because with a trimix rebreather we’re very far away from it… Penny Glover was considered a very accomplished diver. I’m still astonished by the parameters of her ultimate dive. 40 minutes at 80m constitutes a major error for such a competent individual, especially with a student. Those values have to be confirmed, but if they are then the initial reason for their demise has likely been established. PMR: Meaning? BG: This leads me naturally to the third possible cause of accidents, no doubt the most probable in the majority of the cases: the decompression procedure and profile. In theory and because it delivers a mix with variable PPO2, the electronic trimix rebreather optimizes the dive perfectly. Viewed like that this type of gear is the ultimate weapon. Paradoxically the problem resides in the amazing performances of these devices. Their autonomy is such that divers need decompression procedures that are not always mastered. PMR: Do divers disrespect decompression procedures? BG: In general no, except for incidents. At this level, one should consider that divers are technically capable of managing their ascent, speed and stops. The main problems stems from the tables that are used… As long as one stays within durations not exceeding 15 minutes at 80m there isn’t any problem. The MN-78 tables are perfectly adapted and they’re available in “Diving physiology and medicine” by B. Broussole published by Ellipses. Beyond those 15 minutes, it’s an entirely different matter….
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