Blackout. Currents. Rebreather

[northernone]

Do experienced CCR divers regularly switch between CCR and OC for technical dives? Or do CCR divers naturally resist switching back to OC except for rec dives?

The conditions of this dive would seem to have favored the OC diver or CCR diver with scooter. In hindsight, of course.

When a CCR dive goes bad we bail out and become OC divers to sort out the issues.

I still regularly dive OC for shortdives

Scooter absolutely. Caught unprepared I'm not sure I'd have been better off OC I would have needed (rough estimate) six al80s to return to shore along the bottom as I did and the most I've brought along is 5 for these warmwater dives. Being willing to became lost at sea and wait to be picked up would have avoided the issue entirely.

 

[northernone]

Is your BOB a homebuild too? If you're married to the idea of a BOB I would recommend going with an already engineered independent solution, as it seems your current BOb may not possess the necessary flood tolerance required. Something like a KISS Sidekick or SF2 using spheres or small 1L steels make a great, fully self-contained BOB that is pretty flood tolerant, seemingly one of the major contributors to your incident. Worth a look anyway.

You might also consider changing to a "PSCR" style of configuration where you run linked twins as bailout, with another smaller O2 bottle plumbed into the rebreather. Because it's already being plumbed from an external source, provided your loop isn't compromised, you have other available options for gas addition. Since you're solo diving your level of conservatism and redundancy needs to be greater than even an individual bailout plan with a buddy. Put a BOV on the loop if your primary rebreather so you've got time to sort yourself before jumping to the BOB.

Glad you're still around!

Sorry, didn't see your reply.

Absolutely! When I'm ready for a BOB I'll be taking a hard look at well tested unit.

As a result of scaring myself on that dive seeing how close I came I've added a lot more conservatism to my bailout planning. Would have thought an al80 from 150f wouldn't have left me low on gas, even without my BOB. Cave diving gas planning combined with ocean environmental hazards isn't a good mix.

All further use this situation can be, feel free to comment.

Regards,
Cameron

 

[PfcAJ]

I hate to sound cliche but this is an example of overcomplicating a dive and introducing variables that just dont need to exist.

 

[northernone]

I hate to sound cliche but this is an example of overcomplicating a dive and introducing variables that just dont need to exist.

Unnecessary BOB, delayed bailout, not calling the dive? What else stands out to you?

...sure wish I had a couple extra QDs though ; )

 

[PfcAJ]

Unnecessary BOB, delayed bailout, not calling the dive? What else stands out to you?

...sure wish I had a couple extra QDs though ; )

All of those things including the RB itself. Were you using air as dil? I admittedly didnt read every post in the thread, and I can get down with the RB if you had trimix diluent.

A deco rebreather really has no purpose, but as you discovered its something that can divert your mental bandwidth away from real issues. An oxygen bottle is less nonsense and accomplishes the same goal.

QDs on your bottles are fine, they serve a purpose.

 

[northernone]

All of those things including the RB itself. Were you using air as dil? I admittedly didnt read every post in the thread, and I can get down with the RB if you had trimix diluent.

A deco rebreather really has no purpose, but as you discovered its something that can divert your mental bandwidth away from real issues. An oxygen bottle is less nonsense and accomplishes the same goal.

QDs on your bottles are fine, they serve a purpose.

Makes sense from a task loading perspective and with sufficient gas along as an OC dive I would have been safer (similar mix etc).

Bit of a sidetrack: I'd diverge regarding the useful need of a rebreather because I am a photographer. The shallowest I've absolutely needed a rebreather is 2ft deep. Deeper than a snorkel I've found no other way to interact with water critters for more than a breath at a time. Tried bubble defusers and double hose regs but seems the rebreather is the best tool for my mission.

 

[PfcAJ]

Makes sense from a task loading perspective and with sufficient gas along as an OC dive I would have been safer (similar mix etc).

Bit of a sidetrack: I'd diverge regarding the useful need of a rebreather because I am a photographer. The shallowest I've absolutely needed a rebreather is 2ft deep. Deeper than a snorkel I've found no other way to interact with water critters for more than a breath at a time. Tried bubble defusers and double hose regs but seems the rebreather is the best tool for my mission.

And it might be a valid tool for what you want to do, but my suggestion is not to complicate things more that needed. Also, start your dives with full tanks

 

[northernone]

And it might be a valid tool for what you want to do, but my suggestion is not to complicate things more that needed. Also, start your dives with full tanks

That's helpful. Thank you. (Particularly I won't be diving with BOB any time soon, some buddies are worse than nothing!)

And yes, full tanks would have been exceedingly useful.

Thanks!
Cameron

 

[PfcAJ]

That's helpful. Thank you.

And yes, full tanks would have been exceedingly useful.

Thanks!
Cameron

Fwiw, I almost drowned on a dive where I didn't start with full tanks and needed the gas. It sounds so silly but its a real thing.

 

[northernone]

Fwiw, I almost drowned on a dive where I didn't start with full tanks and needed the gas. It sounds so silly but its a real thing.

Can't like that but glad you came through it ok as well.

A few extra relaxed hours waiting for the current to calm would have easily avoided my situation as well.

Hard not to try to get an extra dive out of a fill when fills are hard to come by. But pretty clear it's important. Even though it sounds silly.

Thanks,
Cameron