Dive with isolator mostly closed?

[DAJ]

Is there any reason not to dive with it open but close to closed for faster shutdown? I'm not worried about it being closed unintentionally since I check my SPG frequently and would notice if it wasn't dropping.

Depends on how close to closed it might be.

Tank Valves and Out-of-Air Emergencies

An improperly opened tank valve is often the reason of an out-of-air emergency. DAN experts weigh in on tank valves. Read more.

dan.org

 

[lostsheep]

There is some concern that by having it partly open / closed you might turn it the wrong way in an emergency because you are not up against a hard stop.

IMO, that likelihood is highly dependent on your familiarity with valves and/or threads.

 

[Smache]

There is some concern that by having it partly open / closed you might turn it the wrong way in an emergency because you are not up against a hard stop.

IMO, that likelihood is highly dependent on your familiarity with valves and/or threads.

Makes sense, I'll keep that in mind when practicing

 

[stiebs]

There is some concern that by having it partly open / closed you might turn it the wrong way in an emergency because you are not up against a hard stop.

IMO, that likelihood is highly dependent on your familiarity with valves and/or threads.

It is not unusual for people to turn a thread (valve, tap, nut, bolt) the wrong way when trying to do it from an unfamiliar angle. Such as twisted your arm in a weird way to get to a hard-to-get-to nut, or reaching behind your head to open (err.. close.. err.. hang on..) your isolater.

FWIW I have mine fully open.

 

[Bigbella]

You do realize that's old school thinking for ancient valves, which is not a concern with any equipment from this century?

I was taught much the same; and my most recent tanks -- some Genesis 100s -- are celebrating thirty years, in 2023 . . .

 

[MidOH]

If the loss of my back gas = death. I'd run no manifold and an extra spg. Or sling another tank.

My baby doubles rig is setup like that. But I'm just a rec diver.

 

[KevinNM]

If the loss of my back gas = death. I'd run no manifold and an extra spg. Or sling another tank.

My baby doubles rig is setup like that. But I'm just a rec diver.

People have also managed to die with a full tank that they apparently forgot they had. Massive stress from a dive going totally pear shaped plus being ooa isn’t conducive to clear thinking and competent decision making. Not saying it isn’t a viable choice but it has potential issues too that you have to train to deal with.

 

[MidOH]

I can rec dive my baby rig, hopefully it can help me with further training.

But a valve drill is a major pita. Need to loosen my belt a bit, to do it without pain. Doesn't seem like a good game plan in an actual emergency. If I can just leave my isolator on a shelf at home, and never do that drill again, I'm all for it.

 

[BlueTrin]

Out of curiosity, if you want to do this, wouldn’t it be actually safer to fully close it and open it to equalise every X bars before to close it again, and breathe from the SPG post?

 

[SlugLife]

I can rec dive my baby rig, hopefully it can help me with further training.

But a valve drill is a major pita. Need to loosen my belt a bit, to do it without pain. Doesn't seem like a good game plan in an actual emergency. If I can just leave my isolator on a shelf at home, and never do that drill again, I'm all for it.

I dive sidemount, so maybe it is or is not a fair comparison. However, if something is a pain, I consider that to be a sign that something needs to improve or change. If it's a pain to manipulate normally, it'll be worse in an emergency.

For example, if I go to practice regulator switching, and can't find my other regulator "instantly" I'll consider moving where my regulator is clipped (or more practice). Or, if I'm having difficulty a clip on a piece of gear, I might swap out that clip for another one. If I don't have enough mobility on a reg, I might need a slightly longer hose.

Like I said, I don't dive manifolded doubles, but perhaps the fact that it's a PITA means there's something which can be done to make it less annoying like repositioning the tanks.