Dangerous lies?

[KevinNM]

While I certainly do not advocate violating MODs, the contingency MOD pp of 1.6 is still considered to be safe, and you were well short of that. Moreover, there is a lot of room for safety built into the standards, and there is no hard line that you cross and have a toxic reaction immediately. In the cases of toxicity I know of, the violations were significant, both in terms of the PP and the time. I would not expect you to have any issues going to 1.5 to get a picture. I'm jealous--I've never seen a mola mola.

Even then, it takes time. Typically many minutes unless you totally blow it (like dive 100% to deeper than 60 feet). You don't need to be crazy paranoid about MOD, but also don't ignore the MOD or trust anyone else to test your tanks for you. Oxygen toxcicity is a real thing and is really hard to survive if it happens underwater.

 

[BertStevens]

Even then, it takes time. Typically many minutes unless you totally blow it (like dive 100% to deeper than 60 feet). You don't need to be crazy paranoid about MOD, but also don't ignore the MOD or trust anyone else to test your tanks for you. Oxygen toxcicity is a real thing and is really hard to survive if it happens underwater.

Glad hear someone say this. Took a chamber ride for minor hand tingling 15+ years ago. 100% O2 at 60 feet for 30 minutes. That's a PP of 3! Then 15 minute air breaks. Granted, it's in a dry chamber with no chance of drowning if I convulsed. But everyone acts like going over 1.6 is instant death.

 

[boulderjohn]

Glad hear someone say this. Took a chamber ride for minor hand tingling 15+ years ago. 100% O2 at 60 feet for 30 minutes. That's a PP of 3! Then 15 minute air breaks. Granted, it's in a dry chamber with no chance of drowning if I convulsed. But everyone acts like going over 1.6 is instant death.

For reasons that no one understands, there is a huge difference between the time and depth it takes to get O2 toxicity (much more) in a chamber and the time and depth it takes to get O2 toxicity under water (much less).

 

[northernone]

Glad hear someone say this. Took a chamber ride for minor hand tingling 15+ years ago. 100% O2 at 60 feet for 30 minutes. That's a PP of 3! Then 15 minute air breaks. Granted, it's in a dry chamber with no chance of drowning if I convulsed. But everyone acts like going over 1.6 is instant death.

Excellent observation.

Chamber tender/operator here.

Observation and chatting with the old staff it seems oxygen toxcicity episodes are a few per hundred chamber rides. In a chamber it's no big deal, air break and cushion against injury.

Underwater, we generally drop the reg and drown. (Gag straps on the French o2 rebreathers have been very successful)

That said I'm personally comfortable with ppo2 2.0 for a while and will dip to 2.6 if I want to see something. Provided I'm calm and relaxed.

Perhaps worth noting these are my own personal tolerances and I would not advocate following them.

All that to say, if you exceed MOD, please don't panic and calmly return to a more conservative depth.

 

[dberry]

"Buying and diving with used equipment will kill you"

 

[chillyinCanada]

this was from a DM that upon discovering that we only went to 50 feet on our first dive recommended we immediately do a quick bounce dive to 70 feet so that we would be safe to do the afternoon dive to 60 feet.

OMG!!

 

[thbcthomas]

Having seen any number of panicked divers, I can tell you that the first thing they do is get rid of the mask (by shoving it up on their forehead) and regulator.

Anyone who says that a mask on forehead ISN'T a sign of panic is lying.

In my recent refresher course in a pool, there were 3 others in class and all 3 put their mask on their forehead. They did this on multiple occasions even though they were told not to and we were standing in 5 foot of water. I am pretty sure they were not in distress. In my sons pool sessions which had more people, they all put their mask on their forehead. It seems to me that is a natural thing, much like sunglasses. Most people put them on their head not around their neck.

 

[Edward3c]

When I dove in Crystal Bay, Nusa Penida, Bali, my Balinese DM told me that we might see the Mola Mola deeper than 130', so he blended me EAN27. We saw one being cleaned by Emperor Anglefish around 160', I went down as closed to it as I could (144') to take a good picture of it (see my avatar) & ascended to MOD (137'), where the DM was watching me. That was the deepest dive I made. The only feeling I got was everything was so calm & peaceful.

I'm not surprised you felt "... calm & peacful" you were will into the Narcosis range. People forget the narcotic effect of N2 is still present with a Nitrox fill.

 

[KeithG]

OMG!!

It did not end up being dangerous since we declined to do the bounce dive...

 

[chillyinCanada]

It did not end up being dangerous since we declined to do the bounce dive...

It never occurred to me that you would have.

I'm merely horrified at the guy's ignorance. What else does he think he "knows"?