My first screw up on Boris

Drmike

I have a feeling we are going to need it

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Cave diving is a sport
Wreck diving is a sport
Diving in general is a sport

'Rebreather diving' is not a sport
its the delusional obsession with a highly dangerous and often inappropriate piece of equipment

MikeH

Mike,

What kind of FFM are you using in those pics? Find something that works better than the KM48?

BTW, your PM inbox is full....it won't allow anybody to send you any more PM's.

Mike

JonnyB

That is the Dräger NOVA FFM he is using.

So Mike, tell us, now that youhave used this one for a while... which is the best one m48 or NOVA.

/Jonny

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A quote from Crazyduck - In remembering our own Rob Davies.
"Outbound flight 777 heavy you are cleared for flight
Due west into that warm red Texas sunset
You have angels on your wings and divers memories on your six."

Rest In Peace

http://www.divetekcyprus.com
http://www.diveccr.com

Pete

Yes, Tell us. I'm VERY interested in that answer.
Regards,
Pete

AM

Mike - I am seriously glad you made it out to share the tale!

It's frighteningly easy for a sequence of events to turn into a living nightmare.

Having had a few epics myself on the surface,trying to get back on boats, the last one in a force 6 where I also got pulled under the boat, I have learned a few lessons:

I always keep a surface/shallow breathable dil inboard and keep the hypoxic dil mix offboard with dual plug ins and the inboard gas connected to the mouthpiece OC/DSV. (A switching block on manual rebreathers is an essential item in my view so that offboard gases can be plugged to the loop OR the OC/DSV, 3l onboard diluent doesn't last forever!). Even taking a breath from the OC/DSV and blowing it back into the loop will keep the PPO2 sustainable for a period of time.

This configuration means in any event you can breathe both onboard and offboard gases fully open or closed circuit. As an interesting aside, many rebreather manufacturers recommend in their manuals to avoid using hypoxic diluent inboard.

I had a surface epic in Malta (which I never got around to posting yet as it's really long and I hardly get on the web much) and ended up switching off the loop onto inboard dil (connected via OC/DSV) and it's only in the real instance of needing to abandon the loop that you see the real, lifesaving value of always having surface breathable dil available for immediate deployment via an OC/DSV.

One other recommendation, that has assisted me in the past, is have a one-handed ditchable weight system, with tested deployment - establishing easier bouyancy in treacherous sea conditions does reduce the breathing workload. In the published incident reports, failure to ditch weights was listed as a primary factor in some serious incidents/deaths.

Also, it is useful to have the gases on cross connections so the onboard and offboard oxygen (as well as every other bottle) can be plugged straight into the loop (with both having manual injection method).

It's situations like this where I really don't like the use of HUDs - the surface or shallows to me is the most dangerous part of the dive. The multiple error modes of the HUD in a situation like this leave little room for "motor control/understanding" of several different issues going on. In such a task loaded situation how does one "isolate" which error (in multiple failure modes) to deal with first! Without a HUD, possibly during the dive there would be more assessment of gauges/gas levels and an earlier understanding of gas running out.

There is a strong psychological component in the use of HUDs, to me. I still think the HUD is a great concept IF it is coupled with the normal in-water checks, unfortunately from anecdotal evidence, the HUD does seem to introduce an element of complacency. I still check my gauges of both onboard and offboard O2 in water, just in case of leaks. So the moment there is an issue with ANY source of O2, I'm aware of it, not waiting for the HUD. The HUD just cannot mitigate issues caused by slack pre-dive checks, in this case, the air in the O2 offboard and the failure to recognise the issue with the valve not fully open. This demonstrates that it IS possible for a HUD to be indicating to the diver that all is ok when in fact it is not!

Anyway I am seriously glad you made it out. This is a striking example of just one tiny error nearly costing your life. The smallest things on the surface do tend to turn into the biggest disasters underwater!

Thanks for sharing. Seriously, there are some extremely valuable lessons in there.

Regards

AnneMarie

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Deepthought_reloaded

Heck I felt nausious just reading about it

Thanks for sharing and glad you got away with it


What struck me was how the HUD was causing a sense of false security

Now it's probably a stupid question - I only have a basic understanding of whats going on in your unit but as I understand it you were getting an indicator that the solenoid was firing even though no gas there...

Thinking about failure modes, I can see why a solenoid firing indicator is required, but...

Would there be merit in a pressure transducer somewhere around the solenoid and another indicator on the HUD to show gas pressure was present while solenoid fired...

Stewart McMickan

Many thanks for the story and great you are still here to tell the tail. It was a very worth while read.