New Red Sea tragedy and everlasting stupid bargain of power

[Ayisha]

Being overweighted beyond the lift capacity of a BC could make things very challenging at any depth, but especially depths like those or virtually bottomless dives. You'd be freefalling. Ascending may require dropping weights. Your ears had better equalize really fast too.

Just to descend or break the barrier beyond the first 10 feet or so, we already have more weight than we need for any depth, assuming compression of exposure protection. The only reason we wear whatever amount of weight we wear is to start the descent and maintain the safety stop.

It makes no sense to me to overweight oneself to descend faster. It makes more sense to me and it is safer to be correctly weighted and use efficient breathing and streamlining to descend as fast as you want, even like a rock. For any depth, just exhale deeply and sloooooowly; inhale short and shallow, then repeat. Look down, point the fin tips down, be completely vertical, raise the deflator as high as possible and deflate completely or dump, raise both hands if wanted, be as streamlined as possible. That is, if you must be vertical.

 

[Hetland]

This is not directed at this specific incident, but at several similar incidents I've read over recently. They all have deep dives on air with single tanks in common:

What I see missing from many of these "John Doe dives to xxxfeet/meters on a single tank" threads is the mention of the possible long-term effects of bounce diving. Sure at 28yoa, some guy in the tropics can dive to 200ft on an AL80 every weekend and be fine, but what's going to happen when he's 50? will he have any joints left? I'm certain that regular bounce divers have not seriously considered the consequences, or they would have switched to tech, or shooting their fishies at 80ft instead of 180ft. Another, perhaps more important issue, is oxygen toxicity. While "sally" might be able to tolerate a po2 of 2.0, "joe" could go into a seizure at 1.7. There's no warning for a seizure at depth, and no practical way to determine what number you drop dead at. Add to all this that you are forced to make what are essentially life and death decisions while intoxicated on nitrogen, and I have to ask...

WHY? What's the point?

Just because you CAN do something doesn't mean that you SHOULD. Is there something at 200ft that's not at 100? If there is, is it worth seeing more than once?

Then do it right. Get the proper training, carry redundant gear, learn the risks, and then do the dive.

 

[Red Sea Shadow]

This is not directed at this specific incident, but at several similar incidents I've read over recently. They all have deep dives on air with single tanks in common:

What I see missing from many of these "John Doe dives to xxxfeet/meters on a single tank" threads is the mention of the possible long-term effects of bounce diving. Sure at 28yoa, some guy in the tropics can dive to 200ft on an AL80 every weekend and be fine, but what's going to happen when he's 50? will he have any joints left? I'm certain that regular bounce divers have not seriously considered the consequences, or they would have switched to tech, or shooting their fishies at 80ft instead of 180ft. Another, perhaps more important issue, is oxygen toxicity. While "sally" might be able to tolerate a po2 of 2.0, "joe" could go into a seizure at 1.7. There's no warning for a seizure at depth, and no practical way to determine what number you drop dead at. Add to all this that you are forced to make what are essentially life and death decisions while intoxicated on nitrogen, and I have to ask...

WHY? What's the point?

Just because you CAN do something doesn't mean that you SHOULD. Is there something at 200ft that's not at 100? If there is, is it worth seeing more than once?

Then do it right. Get the proper training, carry redundant gear, learn the risks, and then do the dive.

Could you make your post even more useful by posting some references to consequences of deep bounce diving?

 

[mislav]

Asser, my dear friend, thanks for this thread and condolences on the passing of Dr. Osama.

 

[redseadude]

Well said Hetland, I couldn't agree more. However. In this particular accident I think there were other factors to consider. It appears 2 of the divers were at 35m when they noticed the third diver was much deeper and in trouble. It is a very tough call to make - do you go down to assist and put your own safety at risk? If you don't, then you might regret not doing 'all you can' to save the other diver later. At what point do you stop and say "No, I'm not going to attempt to help this distressed diver".

We could all guess what we would do faced with this difficult decision but I don't think we would know until we were actually put in this situation. You might think you wouldn't put your own life at risk but when you saw the other diver panicking, fighting for his life, you might change your mind. May God bless their souls.

 

[Hetland]

Could you make your post even more useful by posting some references to consequences of deep bounce diving?

It will (or at least should) be mentioned in most dive training texts that:

There is wide inter-individual variability in susceptibility to decompression illness.

Oxygen toxicity
Oxygen is toxic under hyperbaric conditions. As a result, it is unsuitable as a pure breathing gas for all but very shallow dives and a carrier gas must be used with it. The risk of oxygen toxicity is dose dependent (depth, inspired oxygen fraction and duration) although there is considerable inter-individual and intra-individual variability in susceptibility. Long term hyperoxic exposure must generally be limited to around 0.4–0.5 bar in order to avoid pulmonary oxygen toxicity, as applies in clinical practice. Short term oxygen exposure can be much higher but exposure to partial pressures greater than 1.6 atmospheres (atm) (>70 msw breathing air; 6 msw breathing 100% oxygen) may cause acute central nervous system (CNS) toxicity. The manifestations of this are legion and non-specific, but loss of consciousness is common and, in many cases, grand mal seizures occur without prodromal symptoms Seizures spontaneously terminate upon cessation of oxygen inhalation but for unconscious divers who are not immediately rescued, drowning is almost inevitable..

Nitrogen narcosis
Nitrogen is narcotic when breathed under hyperbaric conditions.7 Nitrogen narcosis is characterised by euphoria, intoxication and progressive depression of central nervous system function. The onset is insidious and can result in irrational behaviour, impaired judgement and a false sense of security. Although there is considerable variation in individual susceptibility, performance is impaired in all individuals and short term adaptation to the narcotic effects does not occur. Many divers believe that they can develop resistance to nitrogen narcosis with practice but it has been shown that while habituation reduces subjective symptoms, performance remains impaired. Narcosis induced over confidence and impaired performance represents an important, and probably underestimated, threat to diver safety. In the Australasian diving fatality database, Project Stickybeak, it was estimated that nitrogen narcosis contributed to death in 9% of cases.

Bubble trouble: a review of diving physiology and disease -- Levett and Millar 84 (997): 571 -- Postgraduate Medical Journal

Reason enough not to push limits. Just because you don't get the "bends" does not mean that you are not damaging tissues. This damage might not ever have a bearing on your health, or it could destroy your hearing, joints, and apparently memory, decades down the road. By diving within established protocols, you stack the deck in your favor (though it is no guarantee that you won't get bent). Equipment issues aside, deep bounce diving pushes limits that don't have to be pushed.

 

[Hetland]

Well said Hetland, I couldn't agree more. However. In this particular accident I think there were other factors to consider. It appears 2 of the divers were at 35m when they noticed the third diver was much deeper and in trouble. It is a very tough call to make - do you go down to assist and put your own safety at risk? If you don't, then you might regret not doing 'all you can' to save the other diver later. At what point do you stop and say "No, I'm not going to attempt to help this distressed diver".

We could all guess what we would do faced with this difficult decision but I don't think we would know until we were actually put in this situation. You might think you wouldn't put your own life at risk but when you saw the other diver panicking, fighting for his life, you might change your mind. May God bless their souls.

I understand and agree with your comments. That's why I typed my little disclaimer. I have read several threads recently that involved deep diving, usually without proper training and gear. This particular case differs (in some ways significantly) from many of those other posts, but the subject matter and discussions are similar, and this was the most recent post. My comments are not meant to be disrespectful or to place the divers in this particular incident in a bad light.

 

[Razmataz78]

The one surviving diver - Ales Laharnar - apparantly made a detailed account of the accident on this website:

Taucher.Net - Schwerer TU am 26.12. vor Marsa Shargra

His screen name is Aljo. The site is in German, but the divers account is in English

- Apparently the divers had agreed on a max depth of 50 meters, but Ales Laharnar suspects that the two other divers secretly planned to go deeper!

 

[Red Sea Shadow]

Thanks Hetland.

What I was asking for is specific articles relating bounce dives in particular with the known diving problems (DCS, O2 toxicity, and N2 narcosis).

 

[skipperharis]

Hi
After reading the thread my only comments is don't push the limit if you are not ready and well train and with all the needed assistance is on standby.