Crossbar and isolator valve: do they help?

[Doby45]

I may replace mine with a Vindicator someday--I eyed up that option when I ordered the manifold from DGX. But I decided for my first set of doubles, while I'm still learning, I'd just force myself to check more often. I didn't bother asking, but I figured it's probably what the GUE guys would advise.

The Vindicator does not cause you to check less, if anything I seem to check it more. If I have someone else filling my doubles it is also easy to see from a distance if they have messed with the knob during the fill. I normally fill my own when I am in cave country but locally I had my doubles filled by one of the little school aged tank fillers at my local quarry. When I placed the tanks down the first thing she did was start cranking on the isolator knob, so I asked her why and she had no answer. I told her to open it back up and leave it open.

 

[stuartv]

That is the reason that the one valve I have a Vindicator on is my isolator.

I have tried to develop the habit (and mostly succeeded, I think), that if I touch one valve, I touch (check) them all. Period. Even when I finish a dive and close the posts, I still check (quarter turn closed, then back wide open) the isolator valve.

I'm also trying to solidy the habit of doing a flow check every dive, as soon as I get in the water. If it's a boat dive and there's current at the surface, I feel like it's easy to get distracted and forget. I also (try to remember to) check everything just before I get in (and generally do). But, DMs on the boat virtually always "check" everyone's valves before they splash - even when I have asked them not to touch my valves. I don't trust them, so check, splash, then check everything again just seems prudent. And the best way to not have to get in a scrap with the boat's DM (or captain - I will always lose).

I have a feeling that having a Vindicator might encourage me to not do the physical checks I need to do (substituting a visual check). Anyway, I'm too cheap to buy them anyway....

 

[tbone1004]

fun fact for anyone curious. The founder of the WKPP and namesake of the Hogarthian system, who is still an active cave explorer fwiw, doesn't use an isolator on his doubles... Straight bar

 

[Akimbo]

I always found it odd that doubles manifolds supporting two regulators were not made from a single forging like the single regulator manifold that the US Navy uses... with or without an isolation valve.

 

[gobuyastick]

fun fact for anyone curious. The founder of the WKPP and namesake of the Hogarthian system, who is still an active cave explorer fwiw, doesn't use an isolator on his doubles... Straight bar

Interview with Bill "Hogarth" Main | X-Ray Mag
heres a nice article about Bill himself and he explains why he does what he does

edit: i didnt realise someone already posted the same article

 

[Doby45]

I always found it odd that doubles manifolds supporting two regulators were not made from a single forging like the single regulator manifold that the US Navy uses... with or without an isolation valve.

It cause the Navy has $20,000 hammers.

 

[stuartv]

fun fact for anyone curious. The founder of the WKPP and namesake of the Hogarthian system, who is still an active cave explorer fwiw, doesn't use an isolator on his doubles... Straight bar

Yep. That was discussed in the Interview with Bill Main article that was linked in post 15 by @Patoux01 of this thread.

Fascinating, really. I have seen people post that they have seen or experienced burst disk failures and tank valve O-ring failures. I don't recall seeing anyone post that they had an isolator valve failure. Not that it couldn't happen. It just suggests that it is less common that burst disk or valve O-ring blowouts.

But, Bill Main has decided that the opposite is what he believes - a burst disk or valve O-ring blowout is so unlikely that he doesn't feel the need for an isolator valve to use in dealing with it if it does.

The article says:

He claims that isolators introduce another potential failure point, and he has never had or even seen a manifold failure in 45 years of diving.

He removes a lot of the risk from this bold decision by over-maintaining his own cylinders and manifold, regularly changing tank neck O-rings and servicing the manifold and valves, which he does himself, along with all his other equipment.

I wonder if the author really captured Bill Main's thoughts accurately. Obviously, a "manifold failure" is not the only reason to have an isolator valve. And I wonder how Bill Main would feel about it if he needed to use borrowed/rented/supplied tanks that had no isolator valve (and thus, he didn't do the maintenance on them himself).

 

[tbone1004]

I believe he uses burst disc plugs, but am not sure. I know the plugs are VERY prevalent in Florida, just not often talked about....

 

[stuartv]

I always found it odd that doubles manifolds supporting two regulators were not made from a single forging like the single regulator manifold that the US Navy uses... with or without an isolation valve.

I figured it was because with that the combo of cylinders and bands would have to position the tanks so the center to center measurement lined up perfectly with the ends of the manifold. With the modular approach we actually use, the manifold can be screwed in or out to get the ends lined up with the cylinder centers, even if the bands don't position them perfectly.

 

[Caveeagle]

I believe he uses burst disc plugs, but am not sure. I know the plugs are VERY prevalent in Florida, just not often talked about....

Are you talking about the use of thicker/stronger disk, or an actual plug that goes in place of the burst disk plug?