Multiple deaths diving off NC coast May 10, 2020?

[Barnaby'sDad]

What size tank?

I'm not exactly great on gas consumption and have always used a dive computer with a very liberal algorithm. When I have dived there, in that depth range (100 - 115'), I have always stayed down right up to my NDL and then surfaced (with a proper safety stop) with at least 500 psi in a HP100.

Do you normally stay much shallower than the bottom? Use a small tank? I don't understand how any reasonably experienced diver (implying somewhat halfway decent SAC rate) can run out gas before NDL - if you're using a 100 or larger. I guess if you're swimming moderately hard and a lot - as I guess you might when spearfishing.

HP120. A combination of being toward the high end of the gas consumption scale and spending a lot of time motoring about (teeth hunting).

Shallower than the bottom? Depth wise...I’m talking on the deck rooting around from the moment I hit the sea floor until the moment I head back up the line.

If I remember correctly, I made the turn to head up the line for each dive at something like 2-3 minutes before I hit my NDL.

As a result of my consumption rate, I plan for it and head up the line with gas to spare (not counting my pony bottle). I doubt very much that I’m the only one that would be doing that unless every other diver is content with finishing a 105’ dive with 500psi in their tank (I was shooting to have 800 psi when I surfaced).

 

[Bob DBF]

Regarding the primary donate: I understand that this technique was developed and found to be optimal for a very specific user case: diving in caves,

With the advent of the Air 2, and its clones, I would say there are far more recreational divers today using primary donate than there are tech divers. Now whether or not they and their buddy are practiced and proficient is another story.

 

[Angelo Farina]

With the advent of the Air 2, and its clones, I would say there are far more recreational divers today using primary donate than there are tech divers. Now whether or not they and their buddy are practiced and proficient is another story.

In the resorts where I was working customers equipped with just a primary and Air2 were given (for free) an additional Cressi reg to be mounted on the left post and routed on the left shoulder, ready to be donated.
The Air2 was accepted, but not considered as a valid AAS, which was mandatory.
I have read similar policies being enforced now due to Covid-compliant procedures.

 

[Colliam7]

Where do you see that happening? I have primarily dived with Olympus (Morehead City) and Discovery (Beaufort) and it seems like everyone that I see with rental tanks has steel 100s (or larger).

I am specifically talking about Olympus and Discovery. I see it in Wilmington as well, where some of the more popular dives are a bit shallower. Sure, I see divers with 100s, with 119s, with 120s. But, I still see a majority with 80s. I have worked in a Durham shop for a while, and at one time we prided ourselves on having the largest collection of steel cylinders available for rent in the state. (OK, a possible slight exaggeration, but not far from accurate). But, we did have them, not because we invested in a bunch of steels that we put into rental service, but because people retiring from diving would not infrequently bring them by and give them to the shop. The shop's 'Phoenix fire' of several years ago - from the ashes of which we rose again - essentially destroyed our inventory of steels, and now we have 80s to rent - to people going to the coast to dive. Walk into the fill station cage at Olympus - you will see quite a few 80s. Look at the fills sitting in the shop at Discovery in the morning, waiting for divers to pick them up, and you will see a fair share of 80s. I am not saying that they are 90% of the cylinders. But, there aren't that many HP steels available for rental. At the shop where I teach in VA, we don't have ANY (although we have a nice collection of wonderful steel 72s ). And we have a shop trip going to Morehead this weekend. Guess what divers who don't own their own cylinders, will be using? The acquisition cost of steels is simply much higher, and shops / charter operations are not altogether wild about the investment. In fact, most divers buy AL80s as their first cylinder purchase (I did, several decades ago). There isn't anything wrong with that, it is just reality. But, you raise a good point, so when I am there this weekend, I will do a tally, of what is on the boat, and what I see in the fill area.

When I have dived there, in that depth range (100 - 115'), I have always stayed down right up to my NDL and then surfaced (with a proper safety stop) with at least 500 psi in a HP100.

Stuart, you are simply not an 'average' diver. Having followed your evolution, through your posts, over the years I can say that as a very definite compliment. And, it has nothing to do with experience - i.e. # of dives. You have been a serious 'student' of diving since you started. Many divers are not, despite having 100s and 100s (and 100s) of dives. That doesn't mean they are bad people, or bad divers. It just means that their focus - on monitoring NDL, monitoring gas, thinking about what size cylinder they need, what kind of dive planning they should do before a dive, thinking about the need for carrying a redundant air supply - may not be (aka is probably not) the same as yours. Where you may stay down right to your NDL (I usually do the same) - and, I am willing to bet, monitor your gas supply just as assiduously as you monitor your NDL - others may not pay as much attention to their NDL, or to their gas for that matter. Again, this is NOT criticism, of the divers reported in this thread, or others - it is one Instructor's recognition of the harsh reality of recreational diving.

I don't understand how any reasonably experienced diver (implying somewhat halfway decent SAC rate) can run out gas before NDL - if you're using a 100 or larger. I guess if you're swimming moderately hard and a lot - as I guess you might when spearfishing.

Has there been an accurate statement of what size cylinders the two divers were using? I don't know what they had. Anthony in NC may know, since he knew them personally. But, even assuming they were using 100s, with 30%: the computer is basing NDL on dive time, NOT on gas consumption. If their RMV/SAC rate was like mine (0.7 cfm, which according to a poll underway here on SB right now, is well above the 'reported' average), and they were exerting themselves a bit, I think it is quite conceivable. I like to think I am a 'reasonably experienced diver'. My RMV/SAC hasn't change in 15 years. It is what it is. Perhaps, that was true for the two divers as well. But, as I said in an earlier post, the same diver who is not monitoring their gas (which simply has to have been the case in order for them - both - to run out of gas) is probably not monitoring their NDL either. Good people can still make bad mistakes.

One more comment. I have said this before in the thread, and I will re-iterate it, since there seems to be some desire to emphasize equipment rather than human factors. Two divers died, from drowning. They died because BOTH of them RAN OUT OF AIR, on a dive to 100+ feet. Yes, one ran out shortly before the other - one while at depth, the other during the attempted ascent. But, they both ran out of air. And, that was what caused their deaths. According to an informed description posted in this thread, the video showed a less than optimal attempt to share air with an alternate air source. And, so there has been discussion of regulator configurations, etc. - probably far more than warranted, because THAT was not the proximal cause of their deaths. They ran out of air. And, that was a human factors issue - you are unlikely to run out of air if you are monitoring your air supply. They weren't entangled, they weren't prevented from beginning an ascent earlier, they just didn't go up when their air supply indicated that they should. THAT is the lesson to be learned from this event. OK, maybe the outcome would have been different if they had been using larger cylinders, although there is no reason to believe that would have changed their monitoring of gas supply - they would have just stayed down longer before running out. OK, maybe the timing of the end (not the ultimate outcome, rather just the timing) would have been different if the air share had been smoother. But, in all likelihood, they would have still run out of air on a 100 + ft air-sharing ascent. The equipment factors that might have made a difference: a) if they (both) had a redundant air supply, to which they switched when they got the wake-up call - '@#$%, I am out of air!" - and begun an ascent right then; b) if they had both ditched their weights at the bottom, or on the ascent when the donor's air supply was exhausted, and made an emergency buoyant ascent. The risks and consequences of doing so are obvious, but as is often said, 'better bent than drowned'.

The proximal cause of the their death was not their regulator configuration, or which second stage was donated, or whether it was upside down or right side up, or how long the hose was, or even whether their air-sharing skills were proficient or not. If you focus on those things, you completely miss the point. When you run out of air at 100 feet under the surface, and you panic, even with you buddy nearby (who is very low on air), your chances of survival are quite limited. So, 1) actively plan your dive - time depth, GAS, TURN-AROUND POINTS; 2) carry the equipment you need - e.g. gas supply - to complete it as planned; 3) plan for the worst case scenario when you are diving deep (and there is little / no margin for error); 4) follow the plan, AND monitor your progress throughout the dive.

By all reports, these were good people. They were competent divers. This should not have happened. Do not let it happen to you.

 

[stuartv]

I am specifically talking about Olympus and Discovery. I see it in Wilmington as well, where some of the more popular dives are a bit shallower. Sure, I see divers with 100s, with 119s, with 120s. But, I still see a majority with 80s. I have worked in a Durham shop for a while, and at one time we prided ourselves on having the largest collection of steel cylinders available for rent in the state. (OK, a possible slight exaggeration, but not far from accurate). But, we did have them, not because we invested in a bunch of steels that we put into rental service, but because people retiring from diving would not infrequently bring them by and give them to the shop. The shop's 'Phoenix fire' of several years ago - from the ashes of which we rose again - essentially destroyed our inventory of steels, and now we have 80s to rent - to people going to the coast to dive. Walk into the fill station cage at Olympus - you will see quite a few 80s. Look at the fills sitting in the shop at Discovery in the morning, waiting for divers to pick them up, and you will see a fair share of 80s. I am not saying that they are 90% of the cylinders. But, there aren't that many HP steels available for rental. At the shop where I teach in VA, we don't have ANY (although we have a nice collection of wonderful steel 72s ). And we have a shop trip going to Morehead this weekend. Guess what divers who don't own their own cylinders, will be using? The acquisition cost of steels is simply much higher, and shops / charter operations are not altogether wild about the investment. In fact, most divers buy AL80s as their first cylinder purchase (I did, several decades ago). There isn't anything wrong with that, it is just reality. But, you raise a good point, so when I am there this weekend, I will do a tally, of what is on the boat, and what I see in the fill area. Stuart, you are simply not an 'average' diver. Having followed your evolution, through your posts, over the years I can say that as a very definite compliment. And, it has nothing to do with experience - i.e. # of dives. You have been a serious 'student' of diving since you started. Many divers are not, despite having 100s and 100s (and 100s) of dives. That doesn't mean they are bad people, or bad divers. It just means that their focus - on monitoring NDL, monitoring gas, thinking about what size cylinder they need, what kind of dive planning they should do before a dive, thinking about the need for carrying a redundant air supply - may not be (aka is probably not) the same as yours. Where you may stay down right to your NDL (I usually do the same) - and, I am willing to bet, monitor your gas supply just as assiduously as you monitor your NDL - others may not pay as much attention to their NDL, or to their gas for that matter. Again, this is NOT criticism, of the divers reported in this thread, or others - it is one Instructor's recognition of the harsh reality of recreational diving. Has there been an accurate statement of what size cylinders the two divers were using. Anthony in NC may know, since he knew them personally. But, even assuming they were using 100s, with 30%: the computer is basing NDL on dive time, NOT on gas consumption. If their RMV/SAC rate was like mine (0.7 cfm, which according to a poll underway here on SB right now, is well above the 'reported' average), and they were exerting themselves a bit, I think it is quite conceivable. I like to think I am a 'reasonably experienced diver'. My RMV/SAC hasn't change in 15 years. It is what it is. Perhaps, that was true for the two divers as well. But, as I said in an earlier post, the same diver who is not monitoring their gas (which simply has to have been the case in order for them - both - to run out of gas) is probably not monitoring their NDL either. Good people can still make bad mistakes.

One more comment. I have said this before in the thread, and I will re-iterate it, since there seems to be a desire to emphasize equipment rather than human factors. Two divers died, from drowning. They died because BOTH of them RAN OUT OF AIR, on a dive to 100+ feet. Yes, one ran out before of the other - one while at depth, the other during the ascent. But, they both ran out of air. According to informed descriptions, the video showed a less than optimal attempt to share air with an alternate air source.

Thank you!

Good luck this weekend! I was down there 2 days ago with Olympus. We got out Saturday. I was supposed to be diving with them yesterday and today, too, but we were blown out.

 

[johndiver999]

.....

If you focus on those things, you completely miss the point. When you run out of air at 100 feet under the surface, and you panic, even with you buddy nearby (who is very low on air), your chances of survival are quite limited.

By all reports, these were good people. They were competent divers. This should not have happened. Do not let it happen to you.

So the take away is: Don't run out of air at 100 feet and if you do, don't panic?

My "take away" is even simpler: 100 feet is deep, people screw up and I want a viable Plan B.

My feeling is that, assuming they were reasonably adept at switching second stages and they had adequate redundant systems (e.g., pony bottles), the wife would have switched over without incident and she would have done this at the first realization that she was low on air and BEFORE she began to have difficulty or panic.

She would have easily switched the moment it got a little hard to breathe. There would have been no upside down second stages and even if there were, it would have probably been recoverable. She would have had sufficient air in her primary tank to inflate her BC, even if she was (at the moment) in a negatively buoyant condition.

Larger tanks or dropping lead would not have necessarily prevented nor resolved this situation once it progressed.

Having redundant air (and a little competency in the use of it) would have stopped the accident chain immediately and panic would never have arisen.

Alternatively, you can work from the premise that you (and whatever buddy you have at the moment) will be immune from making errors AND all your gear (and your buddy's) will always work as planned.

 

[Colliam7]

So the take away is: Don't run out of air at 100 feet and if you do, don't panic?

My "take away" is even simpler: 100 feet is deep, people screw up and I want a viable Plan B.

Nothing wrong with that take-away.

Hindsight is, of course, a wonderful thing. And, I can easily get carried away with a lot of couldas, shouldas, and wouldas. So, I think you captured my take-away reasonably well. Don't run out of air at 100 feet. Which means, do all the things you should do, BEFORE you run out of air at 100 feet, to PREVENT running out of air at 100 feet.

I have run out of air in open water, once. At 27 feet. It occurred because I didn't monitor my gas supply. I didn't monitor my supply because I was distracted doing other things (teaching, then collecting equipment). In that case, my buddy was 100 feet away - by intent - reeling in a 100 ft tape, while I was also reeling another in, but from the opposite direction. I survived because the advantage - of shallow depth, and skill experience. I teach people how to do CESAs, regularly. So, when I took a breath, and about 3/4 of the way through it suddenly got harder to breathe, I knew what was probably coming. When I attempted to take another breath and found myself sucking on a vacuum, I knew what I had to do. A CESA. I readily admit, a CESA from 27 feet is quite easy. I don't think I could do one from 72 feet, much less 100.

My feeling is that, assuming they were reasonably adept at switching second stages and they had adequate redundant systems (e.g., pony bottles), the wife would have switched over without incident and she would have done this at the first realization that she was low on air and BEFORE she began to have difficulty or panic. . . . Having redundant air (and a little competency in the use of it) would have stopped the accident chain immediately and panic would never have arisen.

YES. A very cogent description. I particularly like the way you phrased it - 'stopped the accident chain immediately'.

As I said, the the primary 'equipment factor' that might have made a difference would have been redundant air. So, I very much agree with you on that.

Now, a two-part caveat:

a. There is an unfortunately beguiling tendency among some divers to use their pony bottle as part of their primary gas supply, in which case it is no longer 'redundant'; for me that is a big no-no.
b. There is also an unfortunately beguiling tendency among some divers to become complacent when they know they have that back-up; so carrying it means - to me - that I need to be all the more situationally aware. .

MY endorsement of having a redundant air supply is really part of #3 at the end - the 'plan for the worst' part.

Yes, I have done - in the past - dives to depth on a single cylinder, for better or worse because I knew that I monitor my gas, depth and time. The problem is, as you very appropriately point out. 'people screw up', and 'people' could very well include me. And, I have to avoid thinking that I don't need that pony bottle, just because I have 'gotten away with it' in the past.

 

[TrimixToo]

The reg fills of water when removed from the mouth, not when reversed. When you place it back in your mouth, it must be evacuated. This can be accomplished in two ways:
1) expiring
2) pressing the purge button

First, my condolences to friends and family. One of the most terrible things about accidents like this one is that there seems nothing new to be learned from it. This is too often the case. :-(

But the reason I am posting is that there is a *third* way to clear a regulator, and I think it's important for people to know what it is:

3) Using your mouth only (airway closed!), work water in and out. The water will exit the exhaust valve. Air will displace it as you work more water into your mouth. After 3-5 cycles, you will have just air in the reg, and can start to breathe. Think of the working water in part like sipping through a straw. You don't inhale, but you bring the liquid (e.g., a carbonated beverage) into your mouth. Now think about pushing it out through that same straw. Now, just substitute the regulator for the straw. This takes nearly no time--a few seconds. Try it (with a lungful of air in case it takes more than one try!). You'll be surprised at how easy and fast it is, almost as fast as using the purge button.

Just another 2 PSI.

 

[rjack321]

Dives like this are frequently executed, both successfully and safely, using an AL80. For me, this dive, using 30%, would be NDL limited, only 20 something minutes, depending on exact depth.

Please be aware of your own limitations and please, please monitor your gas and NDL

The rule of thumb around here which seems to work out pretty well is that your tank capacity in CF is your max depth for that tank (in feet)
al80s = 75ft dive tanks
hp100s = 100ft dive tanks

So the dive in question at 105 or 107ft would be paired with a lp108, hp119 or larger. This maintains larger reserve volumes consistent with how much gas it takes to get an OOA diver and a buddy to the surface with a safety stop (or at least slowish).

I won't flail the "rock bottom" talk, but an al80 at 105ft is a pretty slim reserve which led to 2 fatalities here. Its not that hard to bring a bigger tank and surface with 900psi as an unused contingency instead of 400psi or less.

 

[scubadada]

The discussion about planning your dive around your gas use and NDL is very important. Say you are going to do a square dive to 100 feet on 32% nitrox, for which the MOD is 111 feet. My Oceanic VT3, running DSAT, would give me an NDL of 30 min. My Teric, running a GF high of 95 would give me a little less time. For illustration, I will use a 2 min descent and 28 min at 100 ft.

My average RMV over the last 1500+ dives is 0.36 cu ft/min. The average in the RMV poll that @Colliam7 referenced is about 0.55 cu ft/min. He states his RMV is about 0.7 cu ft/min.

At an RMV of 0.36, the dive takes 47 cu ft of gas. With an AL80 (77.4) that would leave 30.4 cu ft of gas and a surfacing psi of about 1180. For an RMV of 0.55, the dive takes 71.9 cu ft of gas. That would leave 28.1 cu ft of gas left in a HP steel 100, about 970 psi. At a RMV of 0.7, the dive takes 91.5 cu ft of gas. That would leave 28.5 cu ft of gas in a HP steel 120, about 820 psi.

So, on a dive like this, I would use an AL80. A diver with the average poll RMV would use a HP100. Colliam would probably use a HP120. Each of us would safely complete the dive with a very good buffer supply of gas for contingencies.

If you don't already do so, I would suggest getting an idea of your average gas use. It is a very powerful tool for your safe dive planning.