Casino Point - Avalon, Diver Death 9/5/11

[lamont]

Do some use air more rapidly than others.. because of size and perhapes fitness levels as well as exertion???

quite a lot differently. breathing rates are typically measured in cubic feet of gas per minute (at the surface) and 120# females can hit 0.20-0.30 cu ft / min, while >= 200# guys are usually doing good to be in the 0.50 cu ft / min rate, and the first dive i ever measured my average rate of consumption it was 1.1 cu ft / min. so inexperience, lack of cardiac conditioning, and size of the diver is all going to matter. plus, as well, that as you go deeper you use more gas -- every 33 feet adds another factor to how fast you are using your gas -- so at 100 feet you go through it 4 times the speed you do on the surface (100 / 33 + 1 == 4)

 

[Ken Kurtis]

. . . 120# females can hit 0.20-0.30 cu ft / min, while >= 200# guys are usually doing good to be in the 0.50 cu ft / min rate, and the first dive i ever measured my average rate of consumption it was 1.1 cu ft / min . . .

I've done an informal study of the breathing rates of new divers and have generally found 0.75cfm (surface rate) to be a pretty reliable average rate. Occassionally you may see some very comfortable new divers around 0.50cfm. And you certainly see some nervous ones get it up to 1.5cfm.

As it might relate to this particular incident, breathing rates will go up when you're nervous or anxious, plus will be mutltplied by the fact you're at depth (Boyle's Law). In this particular case, add a little excitement or nervousness due to the fact it was an early dive after certification, first dive of the day, some anecdotal comments about gear fumbling on the stairs, and maybe you start close to a 1.0cfm. Now if you're not sure where you are in the Park (pure speculation on my part but given where they came up, maybe they were unaware of where they were) and if you know you're running low on air, in an absolute worst-case scenario, let's bump it up to 2.0cfm. If they're at a depth of 66 feet (3atm), that translates into an effective breathing rate of 6.0cfm.

If (speculation continuing) they're at 600psi, that's 1/5 of 3000psi which on an 80cf tank is 16cf of air. At 6.0cfm at depth, that'll last two two minutes and forty-five seconds. It's enough time to make the ascent but if you start lolly-gagging, or slow down to look at something, or just have troubles kicking up, there's not a lot of margin for error.

I was having a chat with a fellow dive professional last night and we were talking about the admonition of "end your dive at 500psi." What's usually meant by that - or not added - is "on the surface". But we both agree that most divers hear that as "end your dive by starting your ascent at 500psi." That frequently won't be enough.

I've always advised a depth times 10 rule: Take your depth, multiply by 10, and that's your minimum gas to start ascending. So at 100 feet, when you hit 1000psi, you start up. Arrive at your 15' safety stop with 750psi, hit the surface with 500psi, and you've given yourself some margin of error.

- Ken

 

[Leejnd]

I cannot emphasize strongly enough that an OW certification DOES NOT make a person a diver: an OW certification is analogous to a Learner's Permit for a driver's license... only after a person has successfully completed a Rescue course would I consider them to be a "Diver" - and then only a "New Diver" - before that they simply don't have the necessary training or dive experience to be of any help to another diver should a situation occur, ergo not a competent dive buddy, ergo NOT a competent diver.

This is truly a sad situation, one which could have been avoided.

I agree 100%, and this is exactly the point I was trying to make in an earlier post in this thread. It holds much more weight and credibility coming from an instructor, so thank you for saying it.

Here in SoCal, we have a rather unusual situation that makes us way more prone to new-diver errors and accidents than many other world-class diving destinations. So many of the divers I've met around the world got certified in a warm-water, tropical resort type area, where they got certified by a local dive op and then continued to do some DM-led dives with that op while on vacation. In places like that, most dives are done with a DM guide, so newly certified divers at least have an opportunity to do their first non-training dives led by an experienced diver.

But here in SoCal we don't work like that. The boats here don't send DMs in the water with the divers. We also have numerous shore-diving sites, and of course the dive park, where new divers can go in the water utterly unsupervised. Add to that the fact that our diving here is some of the most challenging in the world - cold water requiring thick wet-suits or dry-suits which limit mobility and flexibility; kelp; bad vis; heavy surf. I can't even imagine feeling competent enough to do an unsupervised dive around here right after OW.

But what can be done about this? It's useless to hold another agency-bashing episode - it's all been said. And the agencies aren't going to change their tune - it's how they make their living, telling people they can take a short class and BOOM you're a diver. The word needs to get out to NEW DIVERS, especially those around here: you are NOT a diver fresh out of OW.

And we experienced divers should be willing to take new divers out for dives occasionally. My husband and I have been asked by DMs on boats several times to take a newbie with us, and we have always said yes...even though I detest diving in teams of three. But I feel an obligation, if only as pay-back for all the experienced divers who took US out when we first started this sport several years ago.

Going forward, if I happen to notice new, unsupervised divers at the park (or on a boat), I will make a point of introducing myself and offering to accompany them on a dive. If we all do this a little more, perhaps we can save some lives.

 

[iztok]

Going forward, if I happen to notice new, unsupervised divers at the park (or on a boat), I will make a point of introducing myself and offering to accompany them on a dive. If we all do this a little more, perhaps we can save some lives.

What a wonderful thought!

I am just worried as a (new) DM if I do that would this be considered a liability of me offering (free) services and some sort of obligation (my insurance is through dive shop so if I do personal dive this would not be covered).

 

[cruiser]

What a wonderful thought!

I am just worried as a (new) DM if I do that would this be considered a liability of me offering (free) services and some sort of obligation (my insurance is through dive shop so if I do personal dive this would not be covered).

If you have a "duty of care" to your dive buddy, then you have liability. Anyway, that's the way it was explained to me.

 

[Leejnd]

What a wonderful thought!

I am just worried as a (new) DM if I do that would this be considered a liability of me offering (free) services and some sort of obligation (my insurance is through dive shop so if I do personal dive this would not be covered).

I have no idea if this is true - if so, it seems unfair and unreasonable, because why should someone be stuck with additional liability on a *fun* dive that does not involve any exchange of money nor any understanding of obligation? But this could be true - insurance rules never cease to amaze me. If that's the case, then I guess those of us who are experienced but have NOT moved on to become DMs or instructors have an even stronger imperative to take new divers out for fun dives whenever we can.

I remain eternally grateful to all the wonderful local divers who took me out when I was brand new. If it wasn't for them I probably wouldn't have continued to dive, because I definitely did NOT feel safe right after OW. Diving has now become my main activity that I do for fun.

 

[blue steal]

Going forward, if I happen to notice new, unsupervised divers at the park (or on a boat), I will make a point of introducing myself and offering to accompany them on a dive. If we all do this a little more, perhaps we can save some lives.

LeeAnne I like your style.
Think I'll start this Sunday at the park.

 

[DandyDon]

A nice idea and good of y'all, but I wonder if it'd be better for the newbies to get them to hire private DMs for those first ocean dives.

 

[Hatul]

The dive guide idea is used in many parts of the world, but not common in the US. Of course if you're going to be a dive guide you have to offer more than just safety, but things to see.

Adam

 

[babygirlbowtie]

What a wonderful thought!

I am just worried as a (new) DM if I do that would this be considered a liability of me offering (free) services and some sort of obligation (my insurance is through dive shop so if I do personal dive this would not be covered).

I work in the medical field, wouldn't you also be protected by the Good Samaritan Law?? My insurance doesnt cover outside of work either.. I would hate to think it would be different for divers being helpful..