Wreck diver killed by leaking computer - UK

[sea_ledford]

For the eccr people how much time did you spend running it manual during training? I did my mod1 on a manual revo. I have a hybrid now mostly run the solenoid at depth but almost always run the low setpoint and manual when ascending or run it manual on reef drifts for practice.

All of it aside from one dive to see how it worked. Or at least left on low set point and manually controlled up to high set point. I was a good 30 hours on my SF2 (after class) before I even set it at high setpoint.

I had a solenoid battery die on one of my training dives, and stayed on the loop the whole way out as well. Manually controlling shouldn't need to be a bail out situation as long as you have a way to monitor PO2.

 

[rjack321]

I respect your posts, you have a lot of experience. But I have to agree to disagree.

It's not "d*cking around" to use a backup PO2 display. Of course, if his can was flooded, that's a different story. But I stand by my statement if the only problem was loss of a controller.

Seriously, I know that in MOD 1, bailout is the answer to everything. But you know very well that lots of CCR training is EXACTLY about how to stay on the loop in a variety of situations. Bailing out has its own set of risks, including incurring more decompression obligation, possible flooding, and managing buoyancy on ascent.

Thumb the dive? Of course. But not sure why you think that a functional CCR with a functional PO2 monitoring system requires bailout.

And from the accident analysis point of view, the question is why PO2 wasn't maintained. Saying that it was because the controller failed doesn't even begin to answer that question.

Just no. 1) Bailing from more than about 65m actually has less deco than a CCR ascent. 2) If your buoyancy is worse on BO than CCR something is seriously messed up - what are you doing in deco at all? 3) I don't even know how you are more at risk of flooding when not on the loop. I guess from venting it. If you aren't prepared to bail start over at MOD1 and do it again.

Dive however you want, but there is more and more an online culture that talks ad nauseum about all the ways to stay on the loop. CCR divers keyboard warriors are proud of all the ways they can dream up to try and diagnose a problem and/or stay on the loop - we are especially good at rationalizing staying on the loop to OC divers. This is totally wrong headed, you aren't as good as you think you are, what you did in training is easy, having a low setpoint and manually injecting O2 you aren't playing for keeps. Your MOD1 was super advanced and added all sorts of helpful tips on how to SCR or fly manually or whatever. Yes sometimes those might be required hail mary techniques to get home. But from a 70m dive with no unplanned excessive stays at depth? Just no.

Thus, here we are AGAIN with a surprisingly uncomplicated failure early in a not especially extreme 70m dive. The deceased had pretty much the maximum amount of BO possible for the amount of required deco. A moment of separation shallow, maybe he was distracted looking for the now missing buddy, or took longer to shoot an extra SMB, it doesn't matter. He passed out and died. It's even more of a tragedy because there was zero reason for him to stay on the loop at all.

Hypoxia doesn't give warnings. You get drowsier and drowsier until you can't even think to bail. It can happen to you too. Your spouse and children will thank you for saying "screw this damn CCR" and bailing.

 

[rjack321]

I had a solenoid battery die on one of my training dives, nd stayed on the loop the whole way out as well. Manually controlling shouldn't need to be a bail out situation as long as you have a way to monitor PO2.

A cave diving exit with an intact primary monitor is a lot easier than a 70m ascent from a wreck with current, one hand on a line, SMB, etc using only a HUD (at most) to read ppO2 in the ocean.

 

[BlueTrin]

Just no. 1) Bailing from more than about 65m actually has less deco than a CCR ascent.

Please can you explain this to a newbie like me.

I thought a CCR would give you the perfect mix for your deco PPO2 wise. How can the bailing out have less deco ? Is that because the ascent is faster ?

 

[davehicks]

Please can you explain this to a newbie like me.

I thought a CCR would give you the perfect mix for your deco PPO2 wise. How can the bailing out have less deco ? Is that because the ascent is faster ?

I don't understand that either. First off, the CCR is not going to do anything perfectly if the computer is dead. Bailing out at 65M would be to a 21% mix or less, maybe switch to a richer mix as you approached 6m assuming it was available.

It's tragic and sad this happened to a diver who had adequate bailout and chose to stay on loop with a broken eCCR. Yet another reason for mCCR in my book.

 

[broncobowsher]

A broken eCCR should be able to be flown just like a mCCR. As I mentioned before, I am not a JJ expert. But I don't see the JJ as all that different from any other CCR.

There is some major pieces of information missing. Lot of blaming the equipment. From my CCR classes, this should have been little more than an annoying reason to end the dive early. There is something missing from the limited information we have on what actually happened. Additional failures, improper emergency procedures, something else went wrong. Probably several things all together.

 

[doctormike]

A broken eCCR should be able to be flown just like a mCCR. As I mentioned before, I am not a JJ expert. But I don't see the JJ as all that different from any other CCR.

There is a difference. mCCR typically has a CMF orifice, while a non-hybrid eCCR does not. So with an eCCR and a dead controller, you are 100% responsible for maintaining your PO2 by pushing the MAV, wheras the PO2 on an mCCR will decay much more slowly (you still have to watch your PO2, especially if you are working hard).

So to support the point that @rjack321 was making about my comment, if you are flying a JJ with a dead controller, you now have to frequently hit the MAV, especially on ascent, since you have lost the automatic O2 injection. While on an mCCR you would have more of a buffer.

 

[rjack321]

Please can you explain this to a newbie like me.

I thought a CCR would give you the perfect mix for your deco PPO2 wise. How can the bailing out have less deco ? Is that because the ascent is faster ?

Below about 60-65m you actually have more deco than you would on OC for the same bottom time. Plug in some numbers into multideco and you'll see the trend. At 100m you have waaaay more deco on CCR than you would on OC for the same bottom time. The "less deco" for constant ppO2 only really applies to multilevel dives less than about 60m. Below that depth you end up with a lot more deco on CCR and bailing to OC reduces your time to surface.

The reason is the lack of gas switches. You can do diluent switches but they are only so-so popular, can be complicated, and you never know exactly what you are breathing because your new dil is mixing inerts with your offgassed inerts. They are a bit of a mathematical artifact and for a 70m dive highly unlikely you would try doing dil switches even if you didnt have another failure going on.

Here's 70m example with a 17/46 backgas/dil (It's a bit hot, was just trying as an example and I dont know what is in common use in the UK) and constant ppO2 of 1.2 vs bailing to 17/46 and EAN50 as a deco gas. After a 30min bottom time the bailout plan is actually 10mins faster to the surface. Don't be afraid of bailing.

DIVE PLAN
Surface interval = 5 day 0 hr 0 min.
Elevation = 0ft
Conservatism = GF 50/75

Dec to 230ft (3) Diluent 17/46 0.70 SetPoint, 60ft/min descent.
Level 230ft 26:10 (30) Diluent 17/46 1.20 (1.32), 92ft ead, 106ft end
Asc to 120ft (34) Diluent 17/46 1.20 SetPoint, -24ft/min ascent.
Stop at 120ft 0:25 (35) Diluent 17/46 1.20 SetPoint, 30ft ead, 57ft end
Stop at 110ft 1:00 (36) Diluent 17/46 1.20 SetPoint, 24ft ead, 53ft end
Stop at 100ft 2:00 (38) Diluent 17/46 1.20 SetPoint, 19ft ead, 48ft end
Stop at 90ft 2:00 (40) Diluent 17/46 1.20 SetPoint, 13ft ead, 44ft end
Stop at 80ft 3:00 (43) Diluent 17/46 1.20 SetPoint, 7ft ead, 39ft end
Stop at 70ft 4:00 (47) Diluent 17/46 1.20 SetPoint, 2ft ead, 35ft end
Stop at 60ft 5:00 (52) Diluent 17/46 1.20 SetPoint, 0ft ead, 31ft end
Stop at 50ft 7:00 (59) Diluent 17/46 1.20 SetPoint, 0ft ead, 26ft end
Stop at 40ft 8:00 (67) Diluent 17/46 1.20 SetPoint, 0ft ead, 22ft end
Stop at 30ft 12:00 (79) Diluent 17/46 1.20 SetPoint, 0ft ead, 17ft end
Stop at 20ft 8:00 (87) Diluent 17/46 1.20 SetPoint, 0ft ead, 13ft end
Stop at 15ft 41:00 (128) Diluent 17/46 1.20 SetPoint, 0ft ead, 10ft end
Surface (128) Diluent 17/46 -20ft/min ascent.

OTU's this dive: 167
CNS Total: 59.4%
Gas density: 5.6g/l



DIVE PLAN - BailOut
Surface interval = 5 day 0 hr 0 min.
Elevation = 0ft
Conservatism = GF 50/75

Dec to 230ft (3) Diluent 17/46 0.70 SetPoint, 60ft/min descent.
Level 230ft 20:10 (24) Diluent 17/46 1.20 (1.32), 92ft ead, 106ft end
Level 230ft 2:00 (26) Trimix 17/46 1.32 ppO2, 90ft ead, 109ft end
Asc to 120ft (30) Trimix 17/46 -24ft/min ascent.
Stop at 120ft 0:25 (31) Trimix 17/46 0.77 ppO2, 38ft ead, 49ft end
Stop at 110ft 1:00 (32) Trimix 17/46 0.72 ppO2, 33ft ead, 44ft end
Stop at 100ft 1:00 (33) Trimix 17/46 0.67 ppO2, 29ft ead, 38ft end
Stop at 90ft 3:00 (36) Trimix 17/46 0.62 ppO2, 24ft ead, 33ft end
Stop at 80ft 3:00 (39) Trimix 17/46 0.57 ppO2, 19ft ead, 28ft end
Stop at 70ft 3:00 (42) Nitrox 50 1.53 ppO2, 32ft ead
Stop at 60ft 3:00 (45) Nitrox 50 1.38 ppO2, 26ft ead
Stop at 50ft 4:00 (49) Nitrox 50 1.24 ppO2, 19ft ead
Stop at 40ft 7:00 (56) Nitrox 50 1.09 ppO2, 13ft ead
Stop at 30ft 10:00 (66) Nitrox 50 0.94 ppO2, 7ft ead
Stop at 20ft 6:00 (72) Nitrox 50 0.79 ppO2, 0ft ead
Stop at 15ft 46:00 (118) Nitrox 50 0.72 ppO2, 0ft ead
Surface (118) Nitrox 50 -20ft/min ascent.

OTU's this dive: 99
CNS Total: 36.4%
Gas density: 5.6g/l

I don't understand that either. First off, the CCR is not going to do anything perfectly if the computer is dead. Bailing out at 65M would be to a 21% mix or less, maybe switch to a richer mix as you approached 6m assuming it was available.

It's tragic and sad this happened to a diver who had adequate bailout and chose to stay on loop with a broken eCCR. Yet another reason for mCCR in my book.

It would be bailing to 16/45ish. Then 50%. You would never do a 70m dive without deco gas on your person.

Orifices can clog and you are then running full manual like this diver. You'll go hypoxic on ascent without LOTS of o2 addition too.

 

[jfe]

If............. My unit is a Hollis Prism 2 with the CANBus electronics ....................

I also dive the Prism2 but the DiveCan unit, which in case of primary failure or leak will not allow water to get into the head where it could affect the controller and you still have the function of the HUD to verify setpoint. I chose the DiveCan unit because of that, didn't like the idea of having electronics hard wired in.
I fly my unit mostly manual but in the event of a primary failure not sure I'll trust in myself completely to ascent on the HUD only. Should I had the Nerd as primary and my handset as secondary, absolutely but not on the HUD. To me personally any failure is bailout time.
Something that came to mind is it's reported he sank 70m at the end, what was the max depth of the dive, any dive deeper than 45m on CCR require Mod 2 training and you'll need a trimix DIL if I'm not mistaken therefore he couldn't rely on the PPO2 of the DIL at 6m which should have been enough to sustain him even in the event of O2 loss. My training tought me to have an optimal bailout mix for my deepest depth as well as suplimentry O2 deco cylinder in case of deco under bailout conditions.

 

[rjack321]

Something that came to mind is it's reported he sank 70m at the end, what was the max depth of the dive, any dive deeper than 45m on CCR require Mod 2 training and you'll need a trimix DIL if I'm not mistaken therefore he couldn't rely on the PPO2 of the DIL at 6m which should have been enough to sustain him even in the event of O2 loss. My training tought me to have an optimal bailout mix for my deepest depth as well as suplimentry O2 deco cylinder in case of deco under bailout conditions.

Relying on the O2 in your diluent for your metabolism is called "semi-closed". Basically flushing the loop every X breaths to replenish the fO2 in there. How many breaths depends on the diluent, the depth, and your workload. But no matter what the dil was, at 6m with no O2 injected or regular loop flushes, the loop will go hypoxic and you will gradually fall asleep, drown, and die.