OOA at 75'

[Van Isle]

Hi gang! I was a participant in an incident at a local wall the other day and I am struggling to find lessons learned.

Location: A deep wall, night dive, temps 46F. Visibility was quite good >40'. The bottom is 160+ and planned depth was 100'.

The divers: a group of 3 AOW level divers. I'm new to diving, ~150 cold water dives. A has several hundred cold water dives but is new (~20 dives) to his drysuit. B is newer to diving having just over 50 dives.

The Dive: I was buddy checked by another diver. A & B say they checked each other prior to the dive. We discussed our intended profiles. I was diving 33%EAN, the other two were on air. I was not explicit in saying that I had a pretty hard (1.4PPO2) bottom of 103', but we did agree that we would not go past 100'. All divers were diving alu 80's with 3000psi fills.

The vis was uncharacteristically good, and we were all together a big group of local divers heading out. It was quite a show, but we three were definitely a dive team, separate from the other 3 teams. The dive progressed and we three hugged the 100' limit, staring waaaay down in to the inky darkness.

Diver A strayed below our 100' limit, down to about 110'. He's a really experienced diver, so although I was worried about his NDL, I was more concerned with staying closer to my PPO2 limit and the least experienced buddy.

We started slowly ascending, still swimming away from the entry. At about minute 20, Diver A showed me "half tank" and we turned our dive. We all continued to slowly ascend, with the air divers basically staying 5 minutes or so above their NDL.

All of a sudden...

Diver A tugs my fin, shows me his SPG which read around 200psi. At 75' on a deep wall on a night dive. I gave him my long hose from my mouth and untucked the extra length. I switched to my secondary.

I signal to diver A "end dive" and we start a very slow mid water ascent. I signalled diver B "end dive." Everything (thankfully) was happening in a really controlled manner. We started our 3 minute safety stop. I showed him my SPG; we had over 1200psi. Diver A handed me my long hose back and switched back to his tank. With about a minute left in the stop we all seemed to lose our buoyancy and ascended to the surface from 12 feet.

Surface checks: everyone was ok. I had over 1000psi remaining.

 

[Van Isle]

Some thoughts:

buddy checks - are for buddies. I neglected to do a buddy check with MY buddies. This could have caused confusion with a panicking diver unfamiliar with long hoses. Although Diver B claims they did a "quick" buddy check and SPGs read 3000psi I question this. A more thorough buddy check would have been explicit in revealing my nitrox mix and MOD of 103'.

complacency - although a 100' cold water night dive is not "routine," it is not something I stress about. I should have been more inquisitive with this experienced diver in a new drysuit. I let my familiarity with the person stand in for familiarity with his skills as a diver which I, in retrospect, didn't really have.

complacency - we had a dive plan and my buddy was blowing it hard. The onus was on me to correct that. He of course was burning through MY air reserve and I was not cognizant of that.

long hose - despite the lack of pre-dive brief on usage, the use of a 7' primary hose and bungied backup was facile and made easy a potentially stressful situation. I can "real-life" recommend it's usage.

lack of procedures - at the safety stop I became task loaded with managing depth, time, navigation to the exit point (desirable to avoid nearby overhead docks/boats), my light, 2 buddies, and then my given-back-to-me long hose. I lost my buoyancy and blew a minute of my safety stop. Not a huge deal for me, but probably a bigger deal for diver A who was deeper for longer, on air, and 20 years older. Practice of skills would enhance the ability to multi-task, and a pre-dive brief of procedures to follow in an OOA beyond the usual "take my long hose, we ascend" to include delegation of tasks such as navigation, depth, time.

Yeah. So. Thoughts?

VI

 

[Peter_C]

The lesson? Your friend needs to learn about rock bottom! Nice write up.

Glad everyone was safe.

 

[SkimFisher]

Some thoughts:

buddy checks - are for buddies. I neglected to do a buddy check with MY buddies. This could have caused confusion with a panicking diver unfamiliar with long hoses. Although Diver B claims they did a "quick" buddy check and SPGs read 3000psi I question this. A more thorough buddy check would have been explicit in revealing my nitrox mix and MOD of 103'.

I don't quite understand this statement. Why is that dependent upon a buddy check? I always make sure to communicate a MOD regardless of a buddy check.

 

[Rainer]

Your friend needs to learn about rock bottom!

Sounds like they all do. It should be discussed in the team before the dive. Can someone post Bob and Lamont's guides? A team plan about when to ascend would have likely solved this entire issue (assuming everyone had the situational awareness to heed any limits). Sounds like the entire team neglected various pre-dive checks.

I really don't get switching the OOG diver off the longhose, though. You say you had 1200psi when this happened and he had 200psi. You ended up with 1000psi, so I'm going to assume your buddy was basically OOG at this point (again, totally, etc). Best just to leave him on your hose and finish the ascent. Let him keep that little bit of remaining gas in his cylinder for anything unexpected that might still occur.

Moving forward, make sure you all talk about what happened and what you can do to avoid similar problems in the future. Don't be confrontational or judgmental, but do be firm. Ultimately, you handled this quite well after the OOG occurred. Now take the time to try avoiding having to deal with the same scenario again.

 

[njedrn]

Sounds like they all do. It should be discussed in the team before the dive. Can someone post Bob and Lamont's guides? A team plan about when to ascend would have likely solved this entire issue (assuming everyone had the situational awareness to heed any limits). Sounds like the entire team neglected various pre-dive checks.

I really don't get switching the OOG diver off the longhose, though. You say you had 1200psi when this happened and he had 200psi. You ended up with 1000psi, so I'm going to assume your buddy was basically OOG at this point (again, totally, etc). Best just to leave him on your hose and finish the ascent. Let him keep that little bit of remaining gas in his cylinder for anything unexpected that might still occur.

Moving forward, make sure you all talk about what happened and what you can do to avoid similar problems in the future. Don't be confrontational or judgmental, but do be firm. Ultimately, you handled this quite well after the OOG occurred. Now take the time to try avoiding having to deal with the same scenario again.

agreed

 

[USCScubaboy]

There was another issue brought up in a different thread regarding diving as a group of three. One important piece of advice given was for the group to designate one person as the leader for the dive. From your report, it doesn't sound like this was done.

 

[gcbryan]

I wouldn't have gone to 100 fsw on a night dive with a newer diver. Maybe 50 dives isn't exactly new and it could be different if I had plenty of prior dive experience with him but 50 dives and new to me I don't think I would be doing that dive.

Only because what happened regarding the OOA is almost guaranteed to happen if they aren't used to diving at 100 fsw and doing it at night only adds to the problem.

 

[Ayisha]

There were several safety issues that have already been identified and all of you will hopefully work on.

Regarding all three of you losing your buoyancy during the safety stop, you don't explicitly say what depth it was at other than losing control from 12 feet to the surface. Surface conditions can be much rougher in the top 15 feet than below that and can be vertically challenging closer to the surface. I'm not sure at what depth you were doing the bulk of your safety stop, but hovering at 20 feet is much easier and safer than the typical 15 feet.

BTW, doing the first stop at 15 feet is already too little too late according to research on deep stops, which you can find on the DAN website. A graduated ascent is considered best of all, with a 2 and a half minute stop at around half-depth, and graduated stops along the ascent including an extended safety stop at 20 feet. The deep stop, according to the research, "beats" the bubble rather than "treating" the bubble after the fact. Something to also consider for future dives...

 

[DandyDon]

I can the implications. Since A had several hundred dives, B just over 50 dives, and the OP with 150 - A&B did buddy checks so it's like A is the implied leader, B is the implied subordinate, OP tags along - kind difficult to say much.

Did A give an excuse for his screw-up? Did I miss that?

I don't quite understand this statement. Why is that dependent upon a buddy check? I always make sure to communicate a MOD regardless of a buddy check.

A better discussion would have been good. So often I try to avoid imposing tho; I try to ask questions but even that can be uncomfortable to some. I've had quiet boat pick buddies who couldn't even tell me what they wanted for a Mod on Nx.