Opinions on Inline Regulator Shutoff Valves for SideMount Diving?

[SlugLife]

Get off here go do some diving Slugmug and some of your wearying theoreticals may be answered

Next time I think of doing something dangerous underwater, I'll report back. Well, maybe not me, but perhaps there will be an article about an "Austin Scubadiver" who....

"A scuba diver has died, happy as a bug,
"Some say, he had the mug of a slug.
"He died or he drowned, at least that's what speculations say
"In the Accidents and Incidents section of ScubaBoard today

"He violated safety protocols. At least one, two, or three.
"Or at least that's what it looks like, to you and to me.
"At least he died, doing what he loved
"So says the obituary, of the SlugMug

 

[Tom_Ivan]

... but shut off whatever I'm not using or in case of free-flow.

This is actually another point against them. If your 2nd stage was free flowing because of a 1st stage failure and high IP you'd probably blow a low pressure hose. Which is a lot less desirable under water than a free flowing reg.

 

[Wibble]

Closing the tank or feathering the valve is definitely an option as needed, and very easy with SM. The few times I get a free-flow, I can usually respond quickly flipping the reg and barely lose any air.

The right answer and the major benefit of sidemount.

It’s good to see these questions as we all learn from them.

Looking forwards to your move to CCR

 

[lexvil]

I have them on my lines, not side mount, never had one cause any problem but I do it with a total failure in mind like a blown experimental seat and they will come off soon since the experiment is over.

they have a use and a place but not much need.

 

[SlugLife]

Looking forwards to your move to CCR

I'm fairly sure I'm looking forward to CCR even more. I just need to save up several $1000.

I have them on my lines, not side mount, never had one cause any problem but I do it with a total failure in mind like a blown experimental seat and they will come off soon since the experiment is over.

they have a use and a place but not much need.

That makes sense. I do experiments from time-to-time as well. Although, I'm not really sure what I'd use one for yet.

 

[halocline]

Although, I'm not really sure what I'd use one for yet.

One theoretical use I could imagine for an inline shut off (I've never had one nor am I interested in one) would be with a dropped stage. If you leave the stage pressurized but valve off, it would prevent any water from migrating up the hose in the event someone bumped the purge. I haven't thought about it before so maybe someone else can come up with a reason that's its a bad idea.

 

[SlugLife]

One theoretical use I could imagine for an inline shut off (I've never had one nor am I interested in one) would be with a dropped stage. If you leave the stage pressurized but valve off, it would prevent any water from migrating up the hose in the event someone bumped the purge. I haven't thought about it before so maybe someone else can come up with a reason that's its a bad idea.

I found another thread on the topic, only skimmed the first 2 pages so far, but the only positive I saw mentioned was precisely that. Closing the switch when you also close the valve. It'll probably be a while before I'm diving with half-a-dozen stage bottles, where closing valves makes sense.

 

[Whitrzac]

Freshwater flowing back into a reg isn't an issue. Once the tank is turned on again all the moisture gets blown back out.

I may be a little more carefull about keeping things charged if it was saltwater, but its still going to take a lot of work to get water to flow back into the first stage.

 

[Wibble]

The one use case that comes to mind for normal stages is for decompression stages: Power up the regulator on the surface, breathe from it, then close the inline shutoff valve. That way the second stage can't empty the regulator hose nor first stage, i.e. no water ingress into the first stage.

When switching to a decompression stage, you've loads of time to work through the NoTox protocol and validate the stage is working before breathing it.

 

[GF99/99]

This is actually another point against them. If your 2nd stage was free flowing because of a 1st stage failure and high IP you'd probably blow a low pressure hose. Which is a lot less desirable under water than a free flowing reg.

The most valid point made here. Installing flow stops is very dangerous and should not be done unless you know the down stream effects or have a good reason for it.

Your second stage is essential an OPV so if you block it off and do not have an actual OPV installed on your first stage you have just created a potential hose bomb.