Out of air at 36m... Team Deco defeat death!

[big_si]

Diving the Cuvier on Neptune out of Dover, The wreck lies upright in about 41m of water. Lots of treasure to be found in the form of crockery and glassware.

I’d been trying to get in the sea since December and had been blown out 4 or 5 times since my last sea dive in October. I’d been to Wraysbury only once during that time so was really looking forward to it. Not an ideal amount of practice to jump in for a 40m deco dive…. (Mistake 1)

I was buddying up with ScubaJay and DoverShark (Adrian) who was sporting his rather snazzy new Bare drysuit!

I was the line man (Dover is 'return to shot' dive) so we dropped to the centre of the wreck on deck level in about 35m, tied off and off we went!
We explored up and down the wreck with generally minimal fuss although I'd been feeling a bit task loaded at various points during the dive due to being out of practice. I’d checked my gauges a few times during the dive and the last time it was at 100 bar. To be honest I was probably a bit task focused at times and didn’t see that much of the wreck… and didn’t check my gauges as often as I should (Mistake 2) and hadn’t considered that during my 6 months of very little diving my SAC may have changed (Mistake 3) :-/

The plan was for 30 mins of bottom time with a 35 mins plan if we wanted to extend a little more. We got back to the shot at 32 mins and the decision was made to have a little dig around to use those last few minutes in the plan before ascending. were about 34 minutes into the dive, We were at 36m and Adrian had just dropped into the top of a hold and was passing out crockery to Jason who was loading it into a goodie bag. It was then that the reg started squeeking a bit and starting to feel tighter.... Terror shot through my mind as I knew exactly what was happening! I was about to run out of air at 36m under the English channel with 40 minutes of stops to perform before I could surface….. FCUK!!!

I flashed Scubajay who was a meter or so in front of meas we maintained a good distance between buddies(Good move 1). He looked at me and didn't do anything for what seemed forever (apparently his first thought was.... "What are you doing? We're not practicing that today!" before realising what was going on (and noticing my eyes were enormous and virtually filling my mask) I grabbed his reg at the same time as he spat it out.

I was pleased to be breathing sweet, sweet air again and was sucking on it like an enthusiastic hooker. I still wasn’t happy though. We were now just over the 35 minute plan. With the stress of it I wanted to get out there as fast as possible and get onto my stage…. Lack of experience diving in a three meant that we went to crap when the brown stuff hit the whirly stuff and as a result Adrian was left behind whilst Jason and I returned to the shot a few metres away and started our ascent. (Mistake 4) Adrian fired his blob and ascended solo safely.

We hit the shot and started an ascent. I was breathing heavily and my buoyancy was all over the place and we felt like we were rising fairly quickly. We needed to do something. Jason flared his fins to slow us. I still had a handful of line and my reel in one hand. I wasn’t able to reel in fast enough so it was a bundle of line. Jason had also spotted this and had made the call to cut the lin. I didn’t see this and decided to drop my reel as it felt like the reel could pull us deeper into the incident pit. 150m Kent Tooling Ratchet reel with yellow line gone... (Good move 2?) If found please return I then forced my stupid brain to calm down. I had gas to breath, I needed to sort out my buoyancy. A dump and a squirt from my suit inflation bottle and we were in control and ascending at a controlled rate.(Good move 3)

At 21m Jason switched to his 50% stage and left me on his twins. I had a stage of 80% so wouldn’t be switching until 9m which felt a scary distance off from 36m but was getting tantalizingly closer and closer… My plan was to have stops at 21m, 18m, 15m and 12m before my gas switch…. This wasn’t going to happen as whilst continuing our ascent Jason showed me his gauge…. It was on Zero and was starting to feel tight…. FCUK not again!!! I switched to my reg to breath off the last of the dregs whilst preparing my stage for when we got to 9m. It worked and all was smooth. (Good move 4) Apparently Jay had checked his gauge just before I went OOG and he was on 110 bar.... I must have sucked it empty in less than 8 mins! (my SAC est. = 100 L / min)

We were now at 9m, we both had plenty of gas to breathe and our buoyancy was sorted. Suddenly everything felt much better. So much so that although a few people passed us / were above us doing stops only Mr Chase noticed when I was on Jay’s long hose and stuck around with us incase his bailout was needed… Evidently we had good, controlled performance under pressure / stress if it wasn’t obvious that we had an issue. (Good move 3)

I missed my stops (12 mins spread) between 21m and 9m so decided that my best approach would be to consider it a more Buhlmann style approach than bubble model and so thought it best to stay shallow for as long as possible and make them up on my 9m and 6m stops and bulk them out using as much gas as I considered safe and made sure I made an extra slow ascent up from there... On looking at the profile




It’s not toooo dissimilar and I guess another model or a different level of conservatism may make some difference to the plans. Obviously this is based on a regular inspiration rate and on gassing which may not have been the case at the critical issue stage at the bottom. All things feel alright… Ego is pretty bruised at the moment though and I’ve got my long suffering fiancée to check me out a couple of times with the 5 min neuro check to test…



I've gone through all sorts of emotions and states of mind between the OOG and now..... Crazy day.... Hating diving, loving diving, being scared of diving, wanting to give up, wanting to do it, being pleased to be alive, being thankful to Jay, being thankful for Mark Powell's training and having gone through that scenario a number of times in training so it wasn’t another thing to worry about…, and overall feeling very embarrassed at being so stupid...... a few things really...

Obviously there are some ridiculous mistakes there which should be learnt from:

-I should have done some build up dives instead of jumping in for a 40m deco dive as my first dive…
-I should have thought that my SAC might have changed after 6 months with only 1 dive and getting lardier...
-I should have asked the others to line off so I could just concentrate on the dive...
-We should have only dived in a three if all comfortable and experienced with it…


Lots of shouldhave's,,,,, Hindsight is a wonderful thing.... It’s even more wonderful on this occasion as I’m actually able to have it!


I’m not looking for judgment from all and sundry on what we should or shouldn’t have done in this situation, Until you’re in the situation I don’t know if you can be 100% sure how you would deal with it. I’m just pleased to have come out the other side of it and wanted to post it as a bit of a warning to others in the hope that it might make someone else think things through a bit more before doing the same.[font=Arial][size=3]






UPDATE

Well obviously this post kicked off a number of discussions around the errors which may or may not have been useful… But from messages I got in one form or another I know that some people have learnt something from it. I would also like to thank all those who sent messages of support or offers of help or someone to talk to, it is much appreciated.

I have been having my own retrospective thoughts identifying all errors whilst reading all of the posts. When I thought I had got over it and had sorted out the logical stuff around it I have today begun having nightmares and flashbacks remembering the feeling of that reg tightening and instantly realizing how deep the shit I was in was… These feelings and thoughts of potential consequences have kept me pretty shaken and I haven’t returned to work this week. This is the stuff that doesn’t factor into the plans when dealing with a situation. Beforehand if I was asked what I would do if I or a buddy went out of gas I’d have answered exactly the same text book answer as everyone else… In the real situation it can be different. The best advice is to do all you can to avoid getting in the situation in the first place as it’s truly not a fun place to be, believe me! I think I was pretty much as close to the edge as I could have possibly been and don’t intend to be there again!


In the various discussions a number of questions came up as I had forgotten to put some things into the original report. To summarize the extra info:

Back Gas - Twin 12’s, 28% nitrox, 210bar at start of dive, isolator open.

Deco Gas – 80% nitrox - Stage was filled early in the year for a shallower dive for which it was more appropriate... a number of dives were blown out between then and now so the cylinder was still full and so 80% was used for this dive. V-planner was used to produce plans for both 50% and 80%. This gave largely common stops between 21m and 9m so similar schedule to follow just with gas switches happening at different depths. Plan was to extend my 6m stop so we both came out at the same time so we decided to go ahead with it.

In hindsight I could have bled off to 100 bar and got an air top to about 50% so there was a common plan… I didn’t.

Tables cut with v-planner based on 41m max depth, and +5 conservatism, 9m/min ascent rate to 6m, 1m/min ascent rate 6 – 0m, SAC setting 18 L/Min.


There were a few failings before the dive even took place...
1. Due to repeated blow outs I ended up with an inappropriate / unmatched deco gas.
2. Also due to these blow outs / working different shifts that restricted mid week practice / other plans at weekends / reluctance to use the gas in a puddle... I wasn't dived up. No excuses.

Failings on the day...
1. Taking on the role of reel man when I wasn't well practiced made me task loaded and distracted.
2. Insufficient gas monitoring due to task loading / complacency
3. Not taking account of any potential changes in SAC over the little diving period when planning the dive.

There were also obviously a number of failings not being able to work in a 3 effectively but I don’t want to drill into them as it would currently just exacerbate the threads which are ongoing at the moment.


During the ascent all went fairly well considering the resources we had remaining. By the time we saw anyone else we were just about ready for me to switch to my deco gas so little extra assistance could be given at that stage. Mark Chase stayed on alert should we need help for the final stage of ascent which was great and I thank him dearly for.



The thing that does surprise me is how radically different my SAC would have to be to have run out of gas. By my calcs it would mean a SAC of about 30 or more. I would have previously completed dives of this kind with a healthy reserve remaining (SAC approx 20)...

It's this incorrect expectation and my complacency with gauge monitoring and was major cause for running out of gas. Obviously even if my SAC has raised that high I'd have seen it coming with better gas monitoring so only have myself to blame and will be correcting this immediately.




My first step towards recovery has been to get back on the horse and dive Wraysbury this morning with Sixsquid. It was a very good, completely uneventful, unexciting dive which was just what I wanted! I nervously and slowly descended down a buoy line to a container and spent 5 or 10 minutes trying to get comfortable. I was just finning up and down the container with helicopter turn at the end. Buoyancy was still ok which made me feel a bit more comfortable. On each length of the container I was practicing unclipping, looking at gauge, reclipping… The D-ring was uncomfortably far back and difficult to access so I’ve now moved it forward so it’s more on my hip and easier to get to.

Second half of the dive was finning randomly around Wraysbury. Didn’t see a lot but I was happy. 25 minutes of (fairly) relaxed diving… Thank fcuk!!

Whilst having a post dive hot chocolate we did some sums and on that dive my SAC worked out to be 32… Some is probably the anxiety, the rest…. I really have no idea why it is now so high…


Next steps are working on fitness when my new bike arrives and getting the practice dives in again and build up the depths again... And of course being more regimented in my planning and gas monitoring.



Update 28MAY08 - Done a couple of dives since this now. All at Wrasybury. On the last couple I noticed that I had a leak where the hose attaches to my bungied 2nd stage... This is tucked quite high under my chin and so wouldn't have really been noticable with the stream of exhaled bubbles. I had it checked out last week and it turns out that the O-ring had been deformed (in a way that the servicing guy had never seen before) and had created a little loop in the O-ring that let gas past it... I checked it out today at Wraybury... No bubbling to be heard and after dive calcs showed a drop of SAC from 30-32 on the last few dives.... to 19 on this one.

I'm glad to have identified the cause of the excessive, unexpected consumption. Obviously it wouldn't have been a factor if checking gauges regularly enough though.

[Johnny Boy]

your alive, thats the main thing. i'm sure my arse would have wobbled too!

[Sixsquid]

Good report and you know what I think

Well done guys Glad to have you all safe and well

[Paul Oliver]

Great post Si, and glad it all worked out well

I will have a look for your reel on the 16th when we go back to her, i know pretty much where it is and as long as we have fair viz should find it

[Captain Deco]

Can you rescue my goodie bag as well. I ditched it during the drama and Brian says he saw it on the deck.

Cheers mate!!

[Paul Oliver]

Originally Posted by scubajay

Can you rescue my goodie bag as well. I ditched it during the drama and Brian says he saw it on the deck.

Cheers mate!!

No you got drool all over my Porthole



OK then

I assume you would like me to put some quality spidge in that for you as well

[Captain Deco]

Originally Posted by Paul Oliver

I assume you would like me to put some quality spidge in that for you as well

Nope. you nicked my porthole!!!

Just the bag will be fine!!! You can help me get some quality spidge though....

[Dave Crampton]

I'm glad to have read YOU'RE report. You are still here & you are uninjured, thats the main thing! Forget the Hindsite guilt thing for this dive, but do use it for your following dives. Learn from your experience (knotice I didn't use the Mis***** word!) Then plan and put into practice you're new conclustions and practices.

Good on you for sharing this, and ignore any snide views of those on here who want to pour scorn on you.

Hope to meet you soon, We will be over at Conor's again soon.

Dave C

[Simon TW]

Gland that it was a happy ending. The fact that you can post about it means that getting back in the water will be no problem.

A bloody big thumbs up to Jay for keeping cool and Chasey for his awareness and for sticking around.

[neilh]

You made it back, that's what counts - and sounds as though you're thinking through what happened so you'll learn from it.

I would Green Chasey for his spot on awareness but I need to spread it around - but good on you mate.