Accident & Incident Discussion - Northernone - aka Cameron Donaldson

[lionfish-eater]

Yes there is a planned Meetup spot.
There is a large crack or split in the edge of the wall.
You can drop into the crack and avoid the current.
From that point they head to shore on an angle to the deco area and the exit

 

[mtngoat2674]

The question was asked earlier in this thread about what Cameron carried for cutting tools. I don't know the answer to that question on this dive but this response gives an idea on his thinking on the matter.

I also would have no way of knowing what he had on that particular dive, but I do know he generally carried a cutting tool. He picked up a little line cutter not long ago that he seemed quite fond of.

 

[mtngoat2674]

I didn't know Cameron personally, but like many others here, I felt as if I knew him through his many insightful posts. I hadn't been on the board in a week or so and was shocked when got back on and learned about his disappearance. Condolences to his friends and family.

The first thing I thought of when the A&I discussion got started was his recent post about his lost scooter...

I'm a relatively new diver and have nowhere near the experience level of Cameron or many others here... but just speaking for myself, If I'd recently experienced an expensive gear loss and found myself facing a similar loss, I might try a little too hard and for a little too long to prevent it from happening again.

RIP northernone

Knowing Cameron, my opinion is that jettisoning gear would not impact his decision-making in the way you describe.

It is something that I've seen influence other divers though, so the idea is sound.

 

[scubadada]

Yes there is a planned Meetup spot.
There is a large crack or split in the edge of the wall.
You can drop into the crack and avoid the current.
From that point they head to shore on an angle to the deco area and the exit

Thanks, would you be able to place that on their route, perhaps related to shore landmarks?

 

[Jiminy]

What is the likelihood of ox toxing on air if your scooter developed a serious leak and went significantly negative at 130 or 150 feet?

 

[Vicko]

What is the likelihood of ox toxing on air if your scooter developed a serious leak and went significantly negative at 130 or 150 feet?

He would sooner run out of gas then get oxtox on air at those, or double than those depths.

 

[scubadada]

What is the likelihood of ox toxing on air if your scooter developed a serious leak and went significantly negative at 130 or 150 feet?

MOD @ 1.4 is 187 ft, @1.6 it is 218 ft, does not seem particularly likely. Now, if he actually had nitrox, as brought up by @ReefHound, perhaps a little more likely

 

[boulderjohn]

Still not likely. You have to violate those depths by a fair amount by a fair amount of time. Example: in one case I know, a diver thought he was diving with air, but he was actually diving with 36%. He was diving in the 160 foot range for about 20 minutes before he toxed. I can give other examples.

Now, you can't count on that kind of buffer, but you don't just violate the limit and go right into convulsions.

 

[Jay]

What is the likelihood of ox toxing on air if your scooter developed a serious leak and went significantly negative at 130 or 150 feet?

Here's a semi-relevant thread, but depths deeper than 150ft weren't discussed .... OxTox (CNS) on Nitrox - what if you briefly exceed MOD significantly.

 

[Akimbo]

Have any of you heard of a OC diver oxtoxing on 1.6 ppo2? I use Ean32-30 on 40-45m dives without worrying to much.

and

Has anyone heard of anyone oxtoxing on air?

It is an issue of exposure time. I can say that the US Navy standard was 2.0 ATA most of my career and I never heard of a military or commercial confirmed OxTox event; certainly not a convulsion. There were many suspicious cases of lesser OxTox symptoms but they could have been caused by Nitrogen Narcosis... or too much libation the night before.

Thousands of First Class Navy Divers were certified to 285' on air -- in surface-supplied gear, not Scuba. Combat swimmers also observed the 2.0 ATA limit on pure Oxygen rebreathers. It is hard to judge what their OxTox occurrence was because so many of their operations are classified. I am NOT advocating that the recreational limit should be 2.0 ATA instead of 1.4. I am saying that the risk is low with relatively short durations.

This discussion might be enlightening: Oxygen Toxicity Limits & Symptoms