Double tanks.

[mwhities]

I could do a full valve drill with ether hand in my 3mm. I know a guy who can do it in his drysuit, but mine doesn't fit quite that well. So, yes, it is possible.

Thanks. I just need to find someone that will allow me to test their doubles to see if I could reach. I'll be in a 3mm shortie or long suit or no suit at all. Shouldn't be to much of a problem then.

Michael

 

[PerroneFord]

Lets look at this realistically.

A set of common manifolded doubles. Left post begins to freeflow. Typical solution is to shut down the left post. If this is not an option such as if the knob is broken off, then we isolate and go home. Effectively, this is exactly what we'd do if that post was deemed "always on". Until it fails, we effectively have all our gas. When it fails, we now have 2/3 of a single tank, or what would have been 1/3 of a double tank. This is exactly why we dive on rule of thirds.

If this is a percieved problem, then carrying a bailout bottle is likely a good idea as is including rockbottom into your gas calculations.

"Saving yourself" is a matter of understanding risk, managing risk, and then executing solutions at the required time. I fail to see how this is any different than a scooter dying mid-dive, a primary light failing mid-dive, etc.

 

[mwhities]

Being that I'm new to this world and totally ignorant about this new world, I rely on you (SB members) to help point me in the right direction to learn, gain knowledge and eventually master it. I don't have all of the experience or knowledge and know I won't for a very long time, if ever, of such happenings. I don't know the risks completely yet as I have to be trained for them still. (I know I can't be trained for every one but, you get my point.)

Hopefully soon I will find a mentor in my area or close enough so that we can meet up and I can get better training than sitting here at the computer asking questions I may never know until I dive them.

Thanks,

Michael

 

[rhlee]

Lets look at this realistically.

A set of common manifolded doubles. Left post begins to freeflow. Typical solution is to shut down the left post. If this is not an option such as if the knob is broken off, then we isolate and go home. Effectively, this is exactly what we'd do if that post was deemed "always on". Until it fails, we effectively have all our gas. When it fails, we now have 2/3 of a single tank, or what would have been 1/3 of a double tank. This is exactly why we dive on rule of thirds.

If this is a percieved problem, then carrying a bailout bottle is likely a good idea as is including rockbottom into your gas calculations.

"Saving yourself" is a matter of understanding risk, managing risk, and then executing solutions at the required time. I fail to see how this is any different than a scooter dying mid-dive, a primary light failing mid-dive, etc.

well, in all fairness, by having an "always on" left post, you are essentially turning any failure having to do with the left post into a double failure (the original failure plus the artificial failure of not being able to shutdown the left post). I would see it as adding an additional risk by way of compounding the inherent risk of whatever would normally cause you to shutdown left.

 

[PerroneFord]

What risk do we lose by not having any knobs, o-rings, or associated failure points over on that side? I am not saying this completely mitigates the risk, but I think it balances the equation some. By essentially doing a straight bar from the left tank to the isolator, we have reduced the available failures on the left side to "tank o-ring" only. That's a pretty small risk.

Under ordinarly circumstances, I would say this configuration is not "optimal", but under the contraints of the original poster, I would say that not having the knob on that side in fact IS the optimal configuration.

well, in all fairness, by having an "always on" left post, you are essentially turning any failure having to do with the left post into a double failure (the original failure plus the artificial failure of not being able to shutdown the left post). I would see it as adding an additional risk by way of compounding the inherent risk of whatever would normally cause you to shutdown left.

 

[rjack321]

Ok I know this is the DIR forum...
First choice would be reaching the left post with the right arm. I know I can do it, slowly though. I cannot do the right side with the left arm, just the way I'm built and old injuries too.

Alternatively, what about a slob knob off the left knob to the left chest D-ring - just inside and above the inflator? In this circumstance I don't see this as a negative, rather a "reasonable accomodation" (ducking and running for cover)

 

[PerroneFord]

rjack,

I tend to agree with you. And that was my first thought. I just didn't know if it could be attached to the left side of the manifold. If so, that's the ideal solution provided the diver cannot reach the left post with the right hand under duress. I know I shure couldn't do it. My lats would laugh at me!

 

[ianr33]

Another possibility (although not DIR) would be to use sidemounts

 

[mwhities]

Side mounts. That'd be fun. No, not really. If I couldn't get doubles to work, I'd just stay with a single and go BIG. As big as I could. Maybe sling a couple 80's on my d-rings.

Thanks to all that have posted and suggested.

Michael

 

[HybridDiver]

Thats smart, Why not just stick with a single and sling two 80. That would make your life little more easy?
Chris