Accident & Incident Discussion - Northernone - aka Cameron Donaldson

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johnyc just so you know 130 was not arbitrary 130 is 3.8 ata of n2 at 4 ata absolute of nitrogen they (not sure who ) said that all diver are impaired to a degree (bill Hamilton told me that years ago and I belive him ) maybe sam miller can add to this im sure he knows

Oh I'm sure it wasn't arbitrary for the US Navy, but in terms of what agencies and clubs consider a delineating metric it's totally arbitrary. CMAS and BSAC are two examples of the 130 foot limit having no bearing on what they consider recreational vs technical.

There's good reason for 130ft/40m being an important marker, but the idea that if you breach that depth you are immediately making a technical dive is just silly. The implication that as soon as you pass 130ft you are making a technical dive is what I disagree with. The WRSTC may disagree with me, but plenty of things disagree with WRSTC as well.

Doesn't mean I don't agree that surpassing this depth is a demonstrably higher risk profile, but it's not a line in the sand.
 
We have no idea what Cameron's profile was after he left his mother.

May be @Sloeber can shine us some lights on Cameron’s dive plan that day, as I got the impression from his post, below, that this dive was not one of a kind & he had done it more than once before.

Cameron entered the water at 2:30pm yesterday with his mother directly in front of Puerto Abrigo harbor. Several minutes into the dive he parted ways with his mother, as planned. This was at 70ft. They normally separate for 5-10 minutes while Cameron drops down to 120-150ft, then he rejoins the mother. They never rejoined.

He was diving sidemount with 2- AL80's at 21% and 5mm of neoprene. He did not have a PLB.

The current is extremely strong, even by northside standards, estimated to 6 knots at times. The slower dive boats have reported having some trouble making headway into the current, so any underwater scooter is likely to not be to useful, either.

We have 2 private planes ready to launch within minutes. They may already but up in the air.

Mexican Search and Rescue has expanded their search area into Puerto Morelas, but as of now they have not launched any air support. The information we are being provided is they do not have any pilots. This is troubling and confusing, but I digress.

I'm positive Cameron made it to the surface. I fully believe he is waiting for us to find him. We need air support assistance. If you know anyone from Cancun, Playa, or Cozumel with private planes please ask for assistance. Even boats will help. You can call me directly in Mexico 987-111-9138 for the most up to date information. Happy to send along flight charts and navigational charts of the search area to any pilots.
 
www.dan.org shows...

Standard plan is limited to 130'/40m
Master and preferred have no depth limit.
Just as an FYI on this, different state and local governments have different rules regarding insurance coverage. If you are an American and try to set up a DAN policy on the website, it will ask you where you live, and the coverage available to you will vary according to your answer. I live in Colorado and do most of my diving in New Mexico, and I have the DAN Preferred plan. If I lived in New Mexico, that plan would not be available to me because of New Mexico insurance laws.
 
May be @Sloeber can shine us some lights on Cameron’s dive plan that day, as I got the impression from his post, below, that this dive was not one of a kind & he had done it more than once before.
That was the reason I ran the selected profile in my previous post. RMV Spinoff from Accident & Incident Discussion - Northernone - aka Cameron Donaldson With his low RMV, it is clear to me that Cameron would have plenty of gas to run this profile under normal circumstances. In reality, we have no idea of what he did after splitting from his mother at about 40 minutes on that day.
 
www.dan.org shows...

Standard plan is limited to 130'/40m
Master and preferred have no depth limit.

Just as an FYI on this, different state and local governments have different rules regarding insurance coverage. If you are an American and try to set up a DAN policy on the website, it will ask you where you live, and the coverage available to you will vary according to your answer. I live in Colorado and do most of my diving in New Mexico, and I have the DAN Preferred plan. If I lived in New Mexico, that plan would not be available to me because of New Mexico insurance laws.

The plans are also different for Canadians.

I just downloaded the Dan Canadian policy handbook and it clearly shows no limit for 'planned max depth covered' on all three plans.
 
That was the reason I ran the selected profile in my previous post. RMV Spinoff from Accident & Incident Discussion - Northernone - aka Cameron Donaldson With his low RMV, it is clear to me that Cameron would have plenty of gas to run this profile under normal circumstances. In reality, we have no idea of what he did after splitting from his mother at about 40 minutes on that day.
I’m confused:
  • Sloeber’s post said “Several minutes into the dive he parted ways with his mother, as planned”
  • Your post says he split from his mother at about 40 minutes.
Do we actually know which was it as there seems to not be any clear picture of the actual dive timeline/ profile that day - lot’s on conflicting info and assumptions on the entire dive?
 
I’m confused:
  • Sloeber’s post said “Several minutes into the dive he parted ways with his mother, as planned”
  • Your post says he split from his mother at about 40 minutes.
Do we actually know which was it as there seems to not be any clear picture of the actual dive timeline/ profile that day - lot’s on conflicting info and assumptions on the entire dive?
I believe I read, maybe here on SB, perhaps from the mother, that they split at about 40 minutes at near the NDL. I certainly could be wrong, perhaps someone else saw the same message.

Remains, we don't know what Cameron did after he parted from his mom.
 
johnyc just so you know 130 was not arbitrary 130 is 3.8 ata of n2 at 4 ata absolute of nitrogen they (not sure who ) said that all diver are impaired to a degree (bill Hamilton told me that years ago and I belive him ) maybe sam miller can add to this im sure he knows
That's rather liberal.

It's pretty well known these days that you're most probably impaired well before 4 ATA pPO2, and besides, gas density and CO2 ventilation starts to become an issue somewhere around 4.5 ATA total pressure.
 
It's pretty well known these days that you're most probably impaired well before 4 ATA pPO2, and besides, gas density and CO2 ventilation starts to become an issue somewhere around 4.5 ATA total pressure.

ITYM "pPN2".

According to e.g. this, 4 bar of O2 at 21% is a bit too much.

(You can also plug in common pPO2 numbers and see where the limits of 60 and 50 and 55 metres come from.)
 
https://www.shearwater.com/products/perdix-ai/

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