Woman critical after West Van scuba diving accident - Canada

[Adobo]

bold added

I am quite sure that rec divers do not need ditchable weight. Rec divers should be weighted correctly as they do not have extraneous gear. Rec divers should be able to swim up their rig if they are weighted correctly to be neutrally buoyant at the end of the dive if their tank were to be nearly empty.

Being able to ditch weight to float a few inches higher at the surface (for someone who is correctly weighted) is very different from the tech concept of ditchable weight, which could be any type of ballast, like a can light, camera equipment, etc.

I agree with you here. The question around ditchable weight, while interesting, is not nearly as important as the question on why the diver would need to ditch weight to stay on the surface at the end of the dive with an empty tank.

 

[DandyDon]

I agree with you here. The question around ditchable weight, while interesting, is not nearly as important as the question on why the diver would need to ditch weight to stay on the surface at the end of the dive with an empty tank.

Some do. A few experiences...

As I said earlier, I prefer slightly negative at the end so I can sink quickly if desired to dodge an approaching craft.

When my home bud was new, on a trip to Coz, he had to overweight a bit to sink as he would not relax and exhale - a common problem with newbies. On the surface, his rental BC barely floated him and I recall him gasping for air once, me repeatedly telling him to put his reg back in his mouth. One more time and I was going for his weights.

Then he borrowed a bigger BC from the group Inst who'd flaked out. Once in the water, we noticed that there was a loose connection. We're both better at checking gear now but getting him down and keeping him down in shallows is still a challenge at times.

And if you read a hundred death threads on this A&I forum, you'll find too many cases where the divers made it to the surface, then sunk, body found later with weights attached.

 

[Adobo]

Some do. A few experiences...

As I said earlier, I prefer slightly negative at the end so I can sink quickly if desired to dodge an approaching craft.

When my home bud was new, on a trip to Coz, he had to overweight a bit to sink as he would not relax and exhale - a common problem with newbies. On the surface, his rental BC barely floated him and I recall him gasping for air once, me repeatedly telling him to put his reg back in his mouth. One more time and I was going for his weights.

Then he borrowed a bigger BC from the group Inst who'd flaked out. Once in the water, we noticed that there was a loose connection. We're both better at checking gear now but getting him down and keeping him down in shallows is still a challenge at times.

And if you read a hundred death threads on this A&I forum, you'll find too many cases where the divers made it to the surface, then sunk, body found later with weights attached.

When I say overweighted, I am not referring to being 1-3lbs overweighted at the end of the dive. That's easy to overcome with a half a lungful of air. And it's certainly easy enough to overcome if you are kicking furiously with fins on (which I would imagine to be the case if the diver was in a panic).

This diver, with an empty tank at the surface (wet suit expanded) presumably moving like crazy was unable to remain at the surface. I don't think we are talking about 1-3lbs overweighted here.

While it is valid to talk about ditching weight and so on, for me, the best way to get ahead of being unable to stay at the surface is to not start out so overweighted in the first place.

 

[Roko]

It's nice to be close to neutral at the end of a dive with an empty tank, but what happens if something goes wrong half way through a dive? At the start of a dive?

My HP100's will swing 7.5lbs from full to empty.

Even if you can still keep your head above the surface in an emergency, if "stuff" is going sideways, do you want to be struggling against that?

I fully agree about proper weighting regardless of ditchable or non-ditchable weight.

 

[Crush]

This diver, with an empty tank at the surface (wet suit expanded) presumably moving like crazy was unable to remain at the surface. I don't think we are talking about 1-3lbs overweighted here.

If she was wearing neoprene, the neoprene compresses slowly (slower than the air in your wing, at any rate) during descent and expands much more slowly upon ascent. It is not uncommon to be more negative at the end of a dive with less air in the tank than you were at the beginning of the dive, especially if the suit is old (e.g., a rental) and the water is very cold. While she may have been "moving like crazy" her motions were not necessarily effective. I would not blame her drowning on being overweighted - we have no way of ascertaining this. What we can see directly contributed to her death was an inability to fill her lift bladder with air and/or she needed to ditch weights. DandyDon is right.

 

[Adobo]

It's nice to be close to neutral at the end of a dive with an empty tank, but what happens if something goes wrong half way through a dive? At the start of a dive?

My HP100's will swing 7.5lbs from full to empty.

Even if you can still keep your head above the surface in an emergency, if "stuff" is going sideways, do you want to be struggling against that?

I fully agree about proper weighting regardless of ditchable or non-ditchable weight.

Agreed. It could happen that at the beginning of the dive and at depth, your wing has a catastrophic failure. It is at this time that you will be most negative - your tank is full of gas, your wing is not holding gas and whatever buoyancy your suit was providing at the surface is all but gone due to compression. Anyway, this scenario only reinforces the idea that a divers should be properly weighted to start out with.

The scenario for this unfortunate diver was completely different though. Her tank was empty so that al80 she was presumably using had swung 6 or so lbs in buoyancy. She is at the surface so the suit is partially recovered from compression and whatever gas she had in her wing at depth has now expanded.

If she is vertical with any leg movement then her fins are generating upward thrust. If with all that she cannot keep her head above water well, I'll put it like this, doing a weight check at the end of a dive with 300psi of gas in my tanks, I got dump every ounce of gas out of my wing and empty out my lungs to re-descend from the surface. That's with 300psi.

 

[Adobo]

If she was wearing neoprene, the neoprene compresses slowly (slower than the air in your wing, at any rate) during descent and expands much more slowly upon ascent. It is not uncommon to be more negative at the end of a dive with less air in the tank than you were at the beginning of the dive, especially if the suit is old (e.g., a rental) and the water is very cold. While she may have been "moving like crazy" her motions were not necessarily effective. I would not blame her drowning on being overweighted - we have no way of ascertaining this. What we can see directly contributed to her death was an inability to fill her lift bladder with air and/or she needed to ditch weights. DandyDon is right.

DandyDon is right about a good many things.

As for the rest of this post, well, I dunno about that.