Accident & Incident Discussion - Northernone - aka Cameron Donaldson

[ReefHound]

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.

Amount of work is also a contributing factor. Maybe work like fighting a strong current. I know you don't instantly spaz the moment you exceed MOD. The reason I brought it up is because, if one's tanks accidentally contained 36% instead of 21%, you wouldn't know it. You don't typically analyze "air" tanks. You would be diving your planned time at your planned depth.

As I said, maybe those closer to Cam know that this was an impossibility. Maybe he filled his own tanks and only had an air compressor. But if he dropped off tanks to be filled by others and picked them up later, it could be a mistake by the fill operator. To that point, maybe it would be worth analyzing Bonnie's tanks for both O2 pct and CO.

 

[Jiminy]

and


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

Perhaps just a silly idea on my part...

The thought was the scooter going significantly negative 40lbs or so due to a flood and getting pulled down to 240ish feet in a rapid descent.

 

[lv2dive]

I’ve heard of an OC diver ox tox’ing on 1.3 PPO2.

I sincerely doubt that is what happened in this situation, however, given the depth, time, and previous exposures without incident.

First of all I apologise to the mods who are going to be cleaning this up.

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.

 

[Dan]

Perhaps just a silly idea on my part...

The thought was the scooter going significantly negative 40lbs or so due to a flood and getting pulled down to 240ish feet in a rapid descent.

and crashing on to barrel sponge along the way, then tumbling down the slope, unable to free himself from the scooter...

 

[ReefHound]

I just spoke to Bonnie, Cameron's mother. She confirms that they separated about 10 minutes into the dive as per usual which is the typical time it took them to swim out to the reef from shore in that area. That is what Henry had shared. I'm not sure where the 40 minute number came from but it never sounded right to me. She also shared that they had a new scooter to replace the one that was lost. She said it was very strong and much stronger than the old one. It had 6-8 hours on it. It was purchased from Kristoff in Playa del Carmen.

Was this a brand new scooter and the 6-8 hours were by Cam? Or he bought a used scooter with 6-8 hours on it? Had Cam ever had this scooter deeper than 100' before?

I keep coming back to the scooter. It's what stood out to me from the initial account and this makes it feel even odder. A sudden catastrophic flood and you have a 40-70 pound anchor pulling you down. Just imaging it scares me. Not sure one could even orient themselves and reach down, like getting dragged by a horse.

 

[Dan]

Was this a brand new scooter and the 6-8 hours were by Cam? Or he bought a used scooter with 6-8 hours on it? Had Cam ever had this scooter deeper than 100' before?

I keep coming back to the scooter. It's what stood out to me from the initial account and this makes it feel even odder. A sudden catastrophic flood and you have a 40-70 pound anchor pulling you down. Just imaging it scares me. Not sure one could even orient themselves and reach down, like getting dragged by a horse.

May be about a week old, judging from the date when he posted this: Lost dive scooter: flotsam

 

[ReefHound]

May be about a week old, judging from the date when he posted this: Lost dive scooter: flotsam

I knew that, what I'm trying to establish is whether Cam had ever had this new scooter to that depth before. But now I recall a post that said he and his mom had done that dive the day before and she went to 140' with him.

 

[ReefHound]

You may be aware of this but for those who are unfamiliar with scooters/dpvs.... although dpvs may weigh 40-80 lbs on the surface, in the water they are neutrally buoyant or they would not be usable.

So in order for this theory to hold water, the scooter:
A) would have to have flooded suddenly in the middle of a dive (not impossible, but unlikely)
B) would have to have ingressed enough water weight to become an “anchor” so quickly that Cameron didn’t have time to deploy his cutting devices to cut the leash.

I’ve done support on project dives where SS scooters have been taken to depths past 300 feet so I personally doubt that it flooded due to depth changes when it was working fine for the first part of the dive.

And I'm trying to establish if Cam had previously used this scooter or if maybe he had bought one with a structural deficiency that caused it to implode. I know that they normally are close to neutral and should be fine at that depth. Or a stiff current drove him (the scooter) into rock.

 

[Colliam7]

So in order for this theory to hold water, the scooter:
A) would have to have flooded suddenly in the middle of a dive (not impossible, but unlikely)
B) would have to have ingressed enough water weight to become an “anchor” so quickly that Cameron didn’t have time to deploy his cutting devices to cut the leash.

I will not speculate on what MAY have happened - I simply don't have enough data.

However, in looking at probabilities that might contribute to a disaster scenario involving a scooter, I fully agree with Kate on the improbability of 'A'. As for 'B', I am having trouble imagining a scenario where I could not unhook from my scooter. (I do not have any information on how Cameron may have rigged his scooter.) For me, at least, unhooking from my scooters (Oceanic Mako, or Halcyon T16), even when either is operating at full forward thrust, is not particularly difficult, and doesn't require a cutting device - the point of attachment is a bolt snap, on a D-ring on my crotch strap. So, I see 'B" as equally improbable.

 

[lv2dive]

@RayfromTX can confirm this but it is my understanding that Cameron previously utilized the scooter in question, not just to 70’ but to 150’

The trigger on one of my former scooters got stuck one time and I acknowledge events like that can be disconcerting; in my case I defaulted to my training and basically intentionally ran it into a rock until I could manually disengage my prop. Cameron likely had much more experience than I did when I had my experience so I would expect he could smoothly handle most scooter failures without incident.

And I'm trying to establish if Cam had previously used this scooter or if maybe he had bought one with a structural deficiency that caused it to implode. I know that they normally are close to neutral and should be fine at that depth. Or a stiff current drove him (the scooter) into rock.