Pick apart my rescue: air-share ascent from 110'

[Schwob]

I think you did very well overall and certainly did right giving him your known good air source first.

That I am also saying that, because it is not described whether you saw him check and test breathe his pony during or before final buddy check. And with the benefit of armchair quaterbacking that I am wondering about. Did you know his pony tank was good and full with a working reg? Being the buddy, he also was your "safety" mechanism so to speak. Did you know (before splashing - did you ask? verify?) if he was diving his pony with the valve open for faster access or with the valve closed for a more assured air supply on case...?

About going deeper than planned. Well if you had a contingency for it and Identified at what pressure you need to depart that depth for a normal safe ascend with enough gas in your tank for you and your buddy for the entire ascend (for in case something ovcurred right at the lowest point, just prior to ascend, then it's all good. If not, then heed what a prior poster wrote. Not critiquing really, more thinking that I need to get that thinking more engrained into myself. It's just so easy to go look first... and then think... (and I am not saying that's what you did).

Did you do the right thing ascending to SS first and then checking his pony (by having him use it or did you check (blow some bubbles out of reg) first?) ? I think you did right by minimizing time at depth to conserve gas and by checking how much gas is being used and how that looks in the big picture of getting to the surface.

Hypothetically, assume you had checked (you may have) his pony's SPG tight down there as the incident occurred. Assume it was empty. Assume all that was left was your own remaining gas supply. Would you have changed anything prior to the SS?
You may have had to cut the SS short, but I am wondering what you or others might have chosen to do under that assumption (purely a what if assumption, should never happen, but, what if...). Would any of you change anything prior to the SS? Maybe speed up the ascend in the low half of the column (e.g. to double speed, which makes it the same proportional pressure change per time unit as ascending regular speed in the upper half of the column) to further minimize gas use and maximise time available to slow down where it matters most?

I am curious about general opinions on the latter, but I am also asking because (unless you were sure there was a full pony there, but hey, that reg could fail), if you think you would have changed something, well that would be good for thought.

The whole description and discussion is great food for thought. Certainly glad it went so well. Thanks to @dewdropsonrosa you really. Somebody ows you beer or some other poison of choice for life (or less if you're generous...) I sure hope that person choses to not be defensive in his coping mechanism and mulls this over hard and learns !

 

[MaxBottomtime]

There are many solutions to a free flow problem. If there is still plenty of air in the tank you could simply inhale while holding the second stage below your mouth. You can also feather the flow by opening and closing the valve or bending the hose to crimp it.

 

[dewdropsonrosa]

Something I forgot to ask... did you have any issues getting to his valve to shut it off?

A very small amount. I think he was confused about what I was trying to accomplish rather than being uncooperative/obstructive.

 

[dewdropsonrosa]

Did you verify that the pony had air in it?

I didn't look at the gauge before the dive, but I did see him turning it on while gearing up. On future dives, I'm going to be more diligent about checking the gauges for alternate air sources.

 

[dewdropsonrosa]

One thing to consider is that with the depth you were diving to your gas plan was not conservative enough. However brief your descent to 41m [~132'] was it was still your deepest depth...at 40meters [~130ft] with an average consumption rate of 25L/min [0.9-1.0 cu. ft./min.] for each diver the pressure you planned to begin ascending should have been more around 165bar [~2300 psi] for 12L tank (AL80) or 140bar for a 15L tank. Those gauge readings include arriving at the surface with 50bar [~700 psi] left in the tank that both divers are breathing off of in an emergency, with an ascent time based on 9m/min [~30fpm] with a 2.5min stop at half the max depth and a 1min stop at 5 meters.

One other thing about your depth...your post reads as if you saw something in the sand and dropped down to check it out....it does not read as if you originally planned to dive to 41 meters [~132']. I can't stress enough that one should "Plan your dive and dive your plan"...you should normally only stray from your plan if there is an emergency...dropping down to check out something in the sand was not an emergency.

Recommend reading up on Rock Bottom.

Good job getting to yourself on your buddy to the surface safely. Luckily things did not go further south than they did.

-Z

I appreciate the recommendation to look further into formal gas planning, e.g. Rock Bottom calculations! This is the next thing on my list.

 

[doctormike]

Strong work!

I think that (1) stopping the free flow, and (2) getting the victim on his alternate air source at some point if his back gas was unusable or became empty are important goals.

However, the FIRST thing with any OOG rescue is to get the victim plugged into a working regulator immediately, which you did. It sounds like the you are doing secondary donate. Not my choice, but certainly plenty of divers use that method. I prefer primary donate, which means giving him your primary and switching to your backup, so you 100% know that an OOG and potentially panicked diver will have have air to breathe immediately from a known working reg. But either way, the victim needs gas NOW.

Ideally, it would be good to sort out everything else out at depth, so you don't have to deal with these things while also managing an ascent. Of course, that depends on how close you are to your NDLs, and whether you have enough time for that. Sorting things out in this case would be (1) trying to stop the free flow by plugging the reg or turning the valve on and off, (2) confirming a full pony and getting the victim on that gas supply. If you couldn't stop the free flow, I would just shut off the victim's back gas - you never know if it will become usable later in the dive. Getting to warmer shallow water may allow the reg to start working again, or you could even feather the valve if for some reason you also were low on gas. No reason to throw gas away at any point in a rescue.

Once the victim is breathing off the pony, you both ascend in a controlled fashion at a safe rate with the rescuer keeping in touch contact with the victim, followed by your normal safety stop (an AL40 should be plenty for that). I would prefer him to be on the pony rather than on your backup second stage since he will still have gas even if for some reason you get separated by current, surge, etc...

Maybe the "kissing distance" thing will get you to rethink the utility of a long hose primary donate configuration. Not that that is the only way to do it, but it might have been helpful in this situation. Don't necessarily need the full 7 feet for an inline cave exit, but 5 feet isn't a bad option. I have a 7 foot hose on my single tank OC reg, works fine.

 

[Marie13]

I went to a long hose primary - 5ft - about a year ago. I never realized how much “nicer” it is doing long hose until my recent SM class. Doing air share via long hose while swimming along was quite the difference than the short hose air share.

A lot of people, not necessarily new divers, don’t seem to like switching regs. I used to be one of those divers, but now because of SM, it’s not been a problem for months.

 

[dewdropsonrosa]

A lot of people, not necessarily new divers, don’t seem to like switching regs. I used to be one of those divers, but now because of SM, it’s not been a problem for months.

I think this connects to your previous point (which may be on the other thread) that panicked divers may be reluctant or delayed in accepting an alternate air source. I think that it happens because they narrow their focus to Problem! Regulator is free-flowing!, not Problem! I do not have a reliable air source right now!

I get it, though - taking a regulator out of your mouth can feel like a risk. @Marie13 and I were doing a sidemount training dive on Saturday. My long-hose second stage free-flowed during a routine switch at about 35 feet. I switched back to the working reg, shut down the free-flowing tank, and re-opened the valve once I had things under control. Did I really want to make my next regulator switch after that? No, but I did.

Having my own free-flow the day before was probably a significant help during this rescue. I was primed to switch to good air and then deal with bad air trouble!

 

[ScubaBunga]

I really have nothing to pick apart on the rescue aspect - not checking their gauge for NDL (to me) is not near as important as getting them up up to safety stop and out with air enough for you. Good rescue execution! I do have some questions about the pre-dive.
You said: "I didn’t uncover this during the pre-dive briefing. Tactical error! All of my instabuddies going forward will have to sit through a much more thorough discussion and preparation."

I've dove the wisconsin several times (with steel 72's so air use was watched closely) - and although I hear the water is clearer than it was a decade ago, it's still a deep, cold water, wreck dive and I would "assume" any captain/dive master taking folks out would know or asked about experience level and mentioned it with regards to insta-buddies. I guess because I offer it, I would assume the new diver would have mentioned it as well. 25 dives is not a lot for that dive considering probably 10 of those were OW and AOW training dives. Lesson learned to always know your buddies experience level, recent dive history, if they've done this type of dive before, general air consumption, gear check, etc. should always be done. It may not have changed the dive one bit, but may have made you more aware and less likely to leave your buddy (to checkout something on the bottom), or maybe reminded him (or you) about the pony and his knowledge of it.

Fun fact - My Dad dove that wreck in the early '60s using steel 72's with jvalves (no depth or air gauge) and finding the wreck by line of sight reckoning! I have no idea how as the shore detail is difficult 5 miles out, but he did. I still have the newspaper articles about it.

 

[caruso]

We ascended almost within kissing distance

Ewwww