Diver dies on 60m deep air dive

[Tortuga68]

The BC inflator was extremely slow, delivering only 30 litres/minute

Thanks for providing some additional information, I did wonder if there was a buoyancy issue when I read about “pulling up the line” on the way to the surface.

In conjunction with the coroners comments we might suppose that negative buoyancy plus work of breathing (gas density & perhaps using a recreational regulator?) along with anxiety/inexperience, and perhaps thermal exposure, contributed to whatever it was that caused her stop stop breathing during the ascent

 

[Tortuga68]

Just qualified - I , but as soon as I started seeing dive fatalities in my news feed ( thankyou padi cookies !) It flags up 'the first mistake' in yr head ( the kit used in this case maybe?)

Unfortunately in this case it seems the first mistake may have been taking along a diver without sufficient experience and training for the planned dive profile. The fact that she was diving single tank while the others were on twins suggests she wasn’t qualified for twinset, which if true would likely also mean no technical qualification (although there are other possible explanations)

 

[drbill]

Diving to 60m (~200’) on air?

I've done many dives to 200 fsw on air. One day I average 180 fsw on three dives (200, 180 and 160 fsw). I certainly don't recommend it to anyone else though.

 

[dmaziuk]

Diving to 60m (~200’) on air?

OxTox time is longer than NDL of ~5 minutes (by the tables that go that deep) and a bounce dive like that should be doable on an AL80, provided you're not hyperventilating from all the excitement. Gotta wonder what's down there to see in a couple of minutes, that was worth the risk, though.

 

[laikabear]

What is the max depth there? Unless they descended to the bottom and she had been unable to add gas to the wing / BCD on the descent and was very negative at the bottom, why would she need to add gas to get back to the surface? Normally you would be venting gas on the way up.

 

[Graeme Fraser]

I dive here regularly. It's a large quarry ranging from 6m to 85m, accessed by long pontoons. Most points of interest are designated by fixed shot lines.

I would guess they entered from the deep area drop off which is where most tech divers kit up and jump. From there you normally descend a 40m shot line alongside the wall which then meets a sloping bottom down to about 70m. This line also branches off to a 9m and 6m deco trapeze. You could surface swim out a bit and take a blue water line straight down, but that's not the norm.

From 35m+ viz is usually pretty good (8m ish). Surface temp fluctuates, but from 40m it stays pretty static at about 7°c.

 

[Griffo]

So.. what exactly is there to see in a quarry at 60m that wasn't at 30m ? (i've never dived in a quarry)

 

[Graeme Fraser]

So.. what exactly is there to see in a quarry at 60m that wasn't at 30m ? (i've never dived in a quarry)

Short answer... not a lot! Most of the POI's are in the 6m - 30m range; the usual helo, APC, plane, chamber, fishing boat, cars, etc. The deep is pretty empty apart from boulders. Off the 40m shot you hit a small boat at 50, a shopping trolley and a laptop computer (which is quite a good nark test).

 

[beester]

OxTox time is longer than NDL of ~5 minutes (by the tables that go that deep) and a bounce dive like that should be doable on an AL80, provided you're not hyperventilating from all the excitement. Gotta wonder what's down there to see in a couple of minutes, that was worth the risk, though.

I'm not worried about Oxtox at that depth diving air. There is some "evidence" that N² narcosis decreases the risk of a CNS hit.

I would be worried about breathing air that feels like breathing pudding at that depth (no matter the type or reg you are using), and hypercapnia. Specially in this scenario where there might have been a BCD malfunction, possible increased breathing rate, etc. In short not being able to ventilate the build up of CO², creating a dark narc, maybe panic. But this is all hypothesis.

What I do have experience with is the effects of gas density and hypercapnia on your narcosis level. Take a nice drift dive to 50m using air in the red sea and nothing will happen. Do that same dive but suddenly you need to fin as a madman against current (brothers isles for example) and suddenly the whole picture changes. Your lungs just can't overcome the effect of death space and gas density and cannot expel CO² sufficiently creating a vicious loopback where you are retaining more and more CO², feel more and more out of breath. But even before you feel out of breath your narcosis level will increase a lot. Same dive, different circumstances. This is fysiology and no experience or competence will change this.

 

[Khrissi]

A good read on the quoted article. Though you guys do many things admirable-the science speaks fr itself. Think I will stick to the 100 fsw n see how I go. K