Equalizing tank pressure at depth

[rstofer]

Get another buddy. There is absolutely NO EXCUSE for running out of air.

Ordinary primary or octo donation will work as will buddy breathing even though it is no longer taught.

Richard

 

[Web Monkey]

have been keeping track of your air consumption and find you have alot of air left in your tank. Keeping your buddy calm you whip out a hose that is hooked up to your 1st stage and connect it to a device that is hooked up to thier 1st stage. You having the higher tank pressure, are now able to donate your air to your buddies tank, equalizing both tanks. You now have more dive time, or at least more time to avert an out of air emergency.
In the typical out of air scenario, you remain attached to your buddy for the most part via an octo. This device would eliminate that.
...
I am not sure if this is really a good idea or not. I am just looking for some input.

Bad idea.

An OOA/LOA diver="dive over". You're not a fill station.

In any event, the best you would get with two same-sized tanks is for both to have 1/2 the pressure of the full tank. For example, you have 1000PSI and your buddy has 0. If you connect the tanks, the best you'll get is 500PSI each, which isn't enough to continue the dive for either of you.

Also, on a personal note, I never give anybody more than one chance to kill themselves on any given dive. If someone needs to share air, I'm happy to assist, but we're going up. No screwing around. No swimming around on my alternate. Just me and OOA going to the surface.

Terry

 

[vladimir]

Imagine this scenario for a second. You and your buddy are at 40' having a wonderful dive seeing the little fishies swim around. Your buddy has lost situational awareness and stopped checking thier SPG.

Why is it that any poster that uses the term "situational awareness" must describe fish as "little fishies"? They're called "fish," or "fishes."

When your buddy does finally check it, the diver realizes that the fish are not so important anymore because they are critically low on air.

It's usually not a critical situation when the fish are low on air. Divers, maybe.

 

[Web Monkey]

All that comes to mind is, how are you going to make a dry connection between the 2 hoses. You could force high pressure water into the reg with the lower pressure.

Also, you would be needing to have 2 high pressure ports on your regs, and some regs only have 1.

Jim Breslin

Also, the HP port in my regs have a hole that I don't think you could get a hair through. A fill just isn't an option.

Terry

 

[Fishpie]

If I was a DM or Instructor working as a dive guide for certified divers dragging 8 or 10 cruise ship passengers around the Rhone (for example) I would love this device. Do the air check after coming out by the mast and the big fella thats on 1000psi while everybody else has 2000 gets an equalizing shot from my tank. No need to cut the dive short for whole group, we even get to see the boilers and mid section....everybody's happy and I have the tips to prove it.

 

[Web Monkey]

If I was a DM or Instructor working as a dive guide for certified divers dragging 8 or 10 cruise ship passengers around the Rhone (for example) I would love this device. Do the air check after coming out by the mast and the big fella thats on 1000psi while everybody else has 2000 gets an equalizing shot from my tank. No need to cut the dive short for whole group, we even get to see the boilers and mid section....everybody's happy and I have the tips to prove it.

I can hardly even begin to describe the ways this is bad.

• You're tied to the hoover for 5 minutes while filling his tank. If anybody in the rest of the group has a problem, too bad for them.
• If he rockets to the surface, so do you. If he drops down to 150, so do you.
• The "big fella" will not give you a big tip, he'll complain how his tank "didn't have enough air"
• The other people won't give you a big tip because "you spent all your time with some big guy"
• I dive with cruise ship passengers every year, and except for the small girls, 2000PSI is about 5 minutes into the dive for a lot of them, although nobody will tell you until they hit 200PSI.
• You're now LOA, so if anybody runs out and comes to you, you're both scre***.

Terry

 

[Reg Braithwaite]

... Besides, the moron has already went OOA once, do you really want to give them a second chance on the same dive. ...

Although phrased as a jibe, there's something there that piques my interest. Something caused an OOG problem. It seems like it's the diver not watching their gauge. If so, they may make the same mistake again, only the next time the OP will have less gas to donate. Bad news!

But what if it's something else, like a leak you haven't noticed? Also bad news!!

Or what if the reason the OOG diver wasn't watching their gauge is because they are narc'd or had a bad fill or have been panting and are now woozy with carbon dioxide buildup?

I really don't have enough experience to say what might be going on, but there's a super-conservative part of me that says when something goes wrong, you don't want to fix it up and carry on unless you are very, very sure you know exactly what the problem is. Otherwise, you may be patching up a symptom but be ignoring the real issue.

Ok, back to finishing my morning

 

[diversteve]

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[Garrobo]

I think it's feasible. Seems to me that you could have high presure quick disconnect fittings on both first stages with a small gate valve on each of them. Have a hose connected to the smarter guy's valve at all times. I doubt that much, if any, water would enter the low-air guy's first stage since they are both under pressure. Beats having your buddy drown wouldn't you agree?

 

[Reg Braithwaite]

Beats having your buddy drown wouldn't you agree?

I agree that given the choice between attempting an underwater transfill and having my buddy drown, I'll try the transfill. But of course, those are not the only two options for dealing with an OOG diver, so I think you may have inadvertently proposed a false dichotomy.