Diving to 130 ft ?

[fnfalman]

My recollection is also that there are unexplained 02 hits just as there are unexplained DCS hits. In other words, it is a bit like saying how am I going to get bent if I don't break the tables. The answer: it happens.

Exactly, sometimes it happens even if you were to do a 1.2 PPO and above 80-ft.

You plan for the worst and hope for the best. Or don't dive at all.

 

[StreetDoctor]

Upon further reflection tied to my thoughts offered above I agree with you on all accounts. Have you looked at O2 related deaths amoung DAN's accident reports? I would be interested with the statistics for this catagory and at what exposures divers ran into trouble...

To be honest with you I have looked at them before and don't recall off the top of my head. I'm not sure if they document a lot of O2 hits though, with their primary focus being recreational. I think you'd find the majority of O2 hits occur during technical dives.

 

[StreetDoctor]

Exactly, sometimes it happens even if you were to do a 1.2 PPO and above 80-ft.

You plan for the worst and hope for the best. Or don't dive at all.

There's a huge difference between an undeserved DCS hit and a freak O2 hit. I would also venture to say that freak O2 hit's are extremely rare, with most of them probably occuring due to a health condition (Lynne any comments?). Another huge difference is if you take an undeserved DCS hit there's a pretty good chance you aren't going to die. If you take an O2 hit and start seizing at 120' your outcome doesn't look very good unless you're diving a full face and have a good buddy that knows what he's doing.

 

[StreetDoctor]

Last I heard (and the thinking might well have changed since my training), Nitrox has no benefit in terms of reducing narcosis. So, 30 vs 32 is neither here nor there in that regard.

Take it a step further and look at oxygen prescribed in the medical field, it's given as an analgesic to help sooth and calm the patient, at least in the prehospital setting. You could argue elevated oxygen makes no difference or is worse in regards to narcosis.

 

[boulderjohn]

Upon further reflection tied to my thoughts offered above I agree with you on all accounts. Have you looked at O2 related deaths amoung DAN's accident reports? I would be interested with the statistics for this catagory and at what exposures divers ran into trouble...

In the most recent DAN report, there is only one fatality that is assumed to be due to CNS toxicity. It is a bizarre case. The diver was an experienced technical diver who was planning a decompression dive using EANx 80--80% O2. He would have, of course, planned to use that only during the shallowest portion of his decompression schedule. He somehow got separated (I am doing this from memory) and was later found dead. The assumption of CNS is due to the fact that his regular tanks were full and his 80% tank was well used. He apparently somehow had mistakenly used 80% while at depth.

There were no O2 toxicity cases in the previous report.

The only other case I know of for sure is even more bizarre. In this case the diver was luckily enough to realize he was about to tox while next to the instructor (George Georgitsis) in a training dive. He was safely brought to the surface despite a seizure, suffering no ill effects. The diver was responsible for doing all the mixes for the dive the day before, and in the confusion he had accidentally put O2 into his tanks when he was supposed to be adding helium, so he got roughly twice the percentage of O2 he was expecting. He compounded the error by not analyzing.

Thus, in the only 2 cases I know, the divers had ridiculously high PPO2's, and they were diving them for a while before they took the hit.

 

[Scott L]

In the most recent DAN report, there is only one fatality that is assumed to be due to CNS toxicity. It is a bizarre case. The diver was an experienced technical diver who was planning a decompression dive using EANx 80--80% O2. He would have, of course, planned to use that only during the shallowest portion of his decompression schedule. He somehow got separated (I am doing this from memory) and was later found dead. The assumption of CNS is due to the fact that his regular tanks were full and his 80% tank was well used. He apparently somehow had mistakenly used 80% while at depth.

There were no O2 toxicity cases in the previous report.

The only other case I know of for sure is even more bizarre. In this case the diver was luckily enough to realize he was about to tox while next to the instructor (George Georgitsis) in a training dive. He was safely brought to the surface despite a seizure, suffering no ill effects. The diver was responsible for doing all the mixes for the dive the day before, and in the confusion he had accidentally put O2 into his tanks when he was supposed to be adding helium, so he got roughly twice the percentage of O2 he was expecting. He compounded the error by not analyzing.

Thus, in the only 2 cases I know, the divers had ridiculously high PPO2's, and they were diving them for a while before they took the hit.

Good post. I beleive halemano's thoughts on the subject made earlier which is refrenced below is food for more thought...

From what I've read you have a greater chance of an "undeserved" DCS hit on a non-deco air dive than to 'Tox at 120-ish on 32%.

 

[offthewall1]

I don't mind flaming...

I think the video of this dive provided by the poster proves the points I made earlier...

I don't think I saw a single sign of life down there... except for the invisible Eagle Ray LOL

Oh I did see a couple of small reef fish in the lower left corner once - that looked like they were narc'ed

After traveling the world (and hundreds of dives in the 100 - 150ft range) with a very wide range of divers and types of divers... here are some thoughts...

1. Going that deep without a specific reason is pointless
2. There is little if any life represented in that depth range on walls (most of it needs more light and warmth.) There are exceptions, such as Black Coral and some shark species etc... that like to cruise the walls at depth.
3. There is a lot of life at this depth range on wrecks - in many places - but not on walls.
4. Best place to see tons of life in the 100 -150ft range is North Carolina, USA. There are more fish per SQF of water on the wrecks than anywhere else on earth.
5. 2nd Best place to see life in this range - Truk Lagoon, Micronesia
6. Not a good place to see life in this range - The Caribbean, Mexico & Central America7. Swimming through a tunnel (overhead environment) at 120ft without proper equipment and training is just plain dumb

As for all the discussion on fitness... if you can hump your own gear without having a heart-attack and climb back on the boat without need of a hoist, you're likely fit enough to dive. The generality of this is simple - we're all human beings... with a ticking time bomb (our heart) inside of us that can give out at any minute. World class athletes have dropped dead of heart-attacks while Uncle Joe who smokes 3 packs a day and has a beer belly bigger than Tiger Wood's Black Book has managed to dive for the past 25 years after gobblin down 2 steak sub sandwiches and a milkshake.

Just because someone is thin and looks fit doesn't mean they're a safe buddy. They're an unknown just like uncle Joe...

Dive safe... Be Happy... Have Fun

Cheers

 

[boulderjohn]

I don't mind flaming...

I think the video of this dive provided by the poster proves the points I made earlier...

I don't think I saw a single sign of life down there... except for the invisible Eagle Ray LOL

Oh I did see a couple of small reef fish in the lower left corner once - that looked like they were narc'ed

After traveling the world (and hundreds of dives in the 100 - 150ft range) with a very wide range of divers and types of divers... here are some thoughts...

1. Going that deep without a specific reason is pointless
2. There is little if any life represented in that depth range on walls (most of it needs more light and warmth.) There are exceptions, such as Black Coral and some shark species etc... that like to cruise the walls at depth.
3. There is a lot of life at this depth range on wrecks - in many places - but not on walls.
4. Best place to see tons of life in the 100 -150ft range is North Carolina, USA. There are more fish per SQF of water on the wrecks than anywhere else on earth.
5. 2nd Best place to see life in this range - Truk Lagoon, Micronesia
6. Not a good place to see life in this range - The Caribbean, Mexico & Central America7. Swimming through a tunnel (overhead environment) at 120ft without proper equipment and training is just plain dumb

As for all the discussion on fitness... if you can hump your own gear without having a heart-attack and climb back on the boat without need of a hoist, you're likely fit enough to dive. The generality of this is simple - we're all human beings... with a ticking time bomb (our heart) inside of us that can give out at any minute. World class athletes have dropped dead of heart-attacks while Uncle Joe who smokes 3 packs a day and has a beer belly bigger than Tiger Wood's Black Book has managed to dive for the past 25 years after gobblin down 2 steak sub sandwiches and a milkshake.

Just because someone is thin and looks fit doesn't mean they're a safe buddy. They're an unknown just like uncle Joe...

Dive safe... Be Happy... Have Fun

Cheers

No flaming, but a simple repeat of what I said before, but with perhaps more needed emphasis.

People go on dives for different reasons. Sometimes it is to see sea life. Sometimes it is not. In the case of this dive, the purpose is to observe and swim through the coral structures, specifically the tunnels.

Saying you should not dive the Devil's Throat because you will not see sea life is like saying you should not visit Paris because there are no good beaches.

 

[MXGratefulDiver]

2. There is little if any life represented in that depth range on walls (most of it needs more light and warmth.) There are exceptions, such as Black Coral and some shark species etc... that like to cruise the walls at depth.

I'm curious how much diving you've done on Vancouver Island. I've been to the walls at Port Hardy down to a depth of about 110 (was only diving singles), and with vis over 100 feet could see much farther down the walls than that. They're not just covered with life ... there's life growing on the life. And as far down as I went and as far down as I could see from there, there was no sign of any letup in the sheer volume of life growing there. I do plan to show up next time with doubles and trimix, just to go see what's down there.

There are deep walls in places like Nootka Sound and Sechelt Inlet where the red gorgonians don't even start to grow till you get well below recreational depths ... and they only get better as you go deeper.

Been to about 135 on Snake Island Wall ... and it's covered in plumose anemones and all the invertebrates that such shelter attracts.

There's way more to see down there than just fish ... some of it way more interesting than fish ... and much of it, like cloud sponges, prefers deep walls ...

... Bob (Grateful Diver)

 

[Rainer]

In this case the diver was luckily enough to realize he was about to tox while next to the instructor (George Georgitsis) in a training dive.

A freak love child of GI3 and AG? Shudder.