Why can't scuba tanks be set up like a firefighter's scba?

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I have often asked myself the same question, but their are many drawbacks including those listed in the replys above. What you also have to consider is the ease of operation for a dive operator. Consider these daily routines.
1) Storing tanks on the boat before the divers set up their gear. Easiest is in rack standing upright.
2) Loading and off loading boat, easiest to just grab the valve and carry
3) Checking all the divers on the boat before they enter the water.
4) Setting up equipment on a rocky boat. Easiest to slip BCD over upright tank and attach reg to top.

Personal diver comfort. Except for Tech divers, how often does a diver need to reach his own valve, (Which is not really that difficult with scuba set up.) Then of course there is hose configuration for the inflator hose.

Basically you could set up your gear either way. But with the many different levels of experience, it is best to have a standardised system, and weighing the pros and cons, valves up wins. This is not to say that if you are diving privately and prefer firefighter system that you cannot set up that way. Just make sure your buddy is familiar with your system and that everything functions as it should. Most industry norms are not rules. As long as you have the correct equipment, set it up as you feel best. As long as its safe.

It can be interesting, but we manage. We dive home-built rebreathers that won't sit in tank stands We find the rewards out way the disadvantages. As for the DM checking my sh.., well, we tell them in advance DON'T TOUCH ANYTHING. You might kill us.

You will off course find the odd operator who will give you grief, but all in all mst will allow you to do it your way if you appear you know what you are doing.

Safe Diving,

Dale
 
AGA Divator had a very nice system like you describe in the mid 70's. Twin HP stl 40's (4400 psi) mounted upside down. Webbing was attached directly to the tank bands. Breathing performance was wonderfull. Hoses were of a somewhat STD length routed up your torso. It was the most comfortable rig I have ever used. Only drawback at the time was air fills (4400 PSI impossible to get in my area)

I dove them in the mid '70's and loved them. Doing penetration was a dream but had to move on to standard tanks as I started going deeper. I am now on a rebreather that is much like the Divators, with all the valving and hoses coming off the bottom.
 
I dove them in the mid '70's and loved them. Doing penetration was a dream but had to move on to standard tanks as I started going deeper. I am now on a rebreather that is much like the Divators, with all the valving and hoses coming off the bottom.

Thats the reason I sold mine in late 1975 & went back to twin 72's.
 
As a theoretical discussion, there is some merit in re-visiting the 'established' way of doing things for critique.

However, in practice for the average (non-specialist) single-tank recreational diver, seeking to invert the cylinder would just be a costly exercise that brought little or no value to their diving. Yes, it can be achieved - at the expense of purchasing regulator 'cages' and custom length hoses. With some ingenuity and tinkering, you could probably even achieve a decent hose configuration. But for what benefit?

As it stands, the valve is conveniently located where it is needed - near the divers' head. It allows the shortest and most efficient hose routings, is easy to assemble and doesn't cost a fortune. It also places the valve/1st stage behind the divers' head, where they will be immediately aware of any air leaks etc.

Technical/doubles/CCR divers may cite the benefit of easier manipulation of valves. Nigel Hewitt (well regarded UK diver) makes a good case for inverted doubles. It goes against the grain compared to what most technical agencies teach, but does provide a solution for those who have a genuine inability to reach/manipulate their valves in a standard (valve-up) configuration. However, a recreational diver - who has immediate access to the surface and no shut-downs required - simply doesn't need to prioritise valve manipulation as a key concern in establishing an equipment configuration.

Add to that the simple fact that the recreational scuba industry is entirely geared-up towards catering for divers using valve-upwards configurations. As others have mentioned, cylinder stands, fill stations, boat racks etc etc are mostly designed upon the basis that the divers' kit will stand upright, using the cylinder base for support. It allows a clean, orderly and space-efficient use of boat decks.

At this stage, I'd be very interested to hear a rationale of why firefighters use an inverted set-up. My assumption is that such a configuration would lend extra protection to the more delicate valve assembly - which may be vital when operating in low-visibility and confined spaces. Also, if smaller capacity cylinders were used, the shorter length of the cylinder (inverted) would be less cumbersome and restrictive - especially with regards to freedom-of-movement of the head/neck. However, I'm not sure if those benefits would realistically translate into scuba diving.

Wreck/Cave divers operate in low-viz and confined spaces... so valve protection is a nice benefit. That said, divers at this level have alternative strategies for protecting their valves - and these tend to be skill-dependant, rather than equipment dependant. Those divers would also be using much higher capacity cylinders (except CCR divers) than a firefighter needs. Inverting those (larger) cylinders wouldn't provide the same benefits as a firefighter obtained.
 
Have you ever noticed that when you travel from North America to Britain everyone drives on the wrong side of the road?

They must need specially built cars,
painting the lines must be awkward
and those must be custom made signs.
They probably also need to receive additional instruction...

I also notice that the French speak a weird language. How do they understand each other?
 
While I can imagine a time when I'd want to be able to turn my valve ON while underwater with a single tank, what that means, of course, is that I've screwed up big time. Solution -- make sure my valve is ON before entering the water and thus I don't need a solution. OTOH, I really can't imagine a time when I'd want to be able to turn my valve OFF while diving a single so, again, no need for the proposed solution. (Note -- IF I had a free flow, for example, I will want my tank turned off -- BUT ONLY AFTER I've gone onto my buddy's gas and then it is trivial for my buddy to turn my valve off.)

Sorry for the hijack, but I like being able to turn my air on and off on a single tank. I might consider switching to an upside-down tank configuration if a convenient and well-designed system were readily available (but it would have to be portable and able to be fitted to rental tanks).

I admit that the primary reason I like being able to reach my valve is to turn ON my air as part of my final pre-entry routine. It is the last thing I do before entering the water, and I do it after getting completely geared up. On boat dives, I usually do it while seated and equipment checks were all done earlier during tank setup. I know that my air is always off during the boat ride and while gearing up upon arrival at the dive site. When the boat crew offers to turn on my air, I just smile and do it myself.

But to specifically address your “not needed” comments, there has been one occasion when I deliberately shut OFF my air underwater and turned it back on. I had descended to approximately 23 meters when my wing inflator hose “popped” off when I started to add some air. Granted, this happened because the connection wasn’t fully seated in the first place, but at that point I had a choice to make: either return to the surface or fix it where I was. After establishing neutral buoyancy manually, I tried several times to reconnect the hose, but with the line pressurized, it just wouldn’t lock. I got my dive buddy’s attention and he tried; still wouldn’t work. So, with his octopus standing by in case I needed it, I took a full inhale, reached back and shut off my air, reconnected the hose, and turned my air back on; all while drifting along in a mild current. Twenty-five seconds without air, then the dive continued as planned. No doubt, those of you who only dive with buddies will say that this would be a risky maneuver to try solo, and I agree. Still, for me it was a confidence-building experiment; I now know that if I have to do something like that myself, I can. Maybe it’s not a common occurrence, but I personally know of two other people who have lost their inflator hose connection while under water, and both returned to the surface.
 
I was thinking back to my firefighting days and I was wondering why scuba tanks can't be set up like scba. Unlike diving, when I was firefighting, I never hit my head on the tank or tank valve and could easily look up. Plus the regulator was easy to reach should there be an air leak or other issue.

Skipping most all of the other post this may have already been answered. Most of the time when diving the tanks are set up for ease of suiting up and in water situations that may arise. Though there are some configurations that allow for tanks being upside down it just makes it easier to be able to sit back and let the tank fall into a tank holder on a boat and remove the gear and stand up and walk away. With upside down configurations (There are actually some set ups similiar to firefighters) you have to employ special protections from bumping the valve against the boat seat or from sliding out of a tank band and hitting the ground valve first. Again there are tanks and devices that are designed to protect the valve.

The other issue is the natural movement of water is you swim forward so all of the current typically will be flowing back wards. This causes a lost regulator to flow away from the diver and therefore you have to reach under you and attempt to follow the hose back to the reg should it get away from you.

Again its not an impossible set up its just not a very common setup.
 
Sorry for the hijack, but I like being able to turn my air on and off on a single tank. I might consider switching to an upside-down tank configuration if a convenient and well-designed system were readily available (but it would have to be portable and able to be fitted to rental tanks).

And that's the show-stopper. Convenience, design, portability, compatibility and cost are the limiting factors.

It is possible to manipulate the valves on a single tank, providing you don't have injury/mobility issues with your shoulder/s or neck. I learnt to do shut-downs in doubles then quickly discovered that the same principles apply to a single tank. If you can get to the isolator on a set of doubles, then you can get to the valve on singles.

I still don't see that the benefits are worth the cost or money however. There's plenty of skill-based solutions that provide the same end results.

I admit that the primary reason I like being able to reach my valve is to turn ON my air as part of my final pre-entry routine. It is the last thing I do before entering the water, and I do it after getting completely geared up. On boat dives, I usually do it while seated and equipment checks were all done earlier during tank setup. I know that my air is always off during the boat ride and while gearing up upon arrival at the dive site. When the boat crew offers to turn on my air, I just smile and do it myself.

I turn the gas on before kitting, but I do also complete a last-minute check once geared up (never let it be said that human error can't occur - especially when responsible for/supervising trainees). I don't need an inverted tank to accomplish this - I doubt the average diver would either, if correct body mechanics are employed.

But to specifically address your “not needed” comments, there has been one occasion when I deliberately shut OFF my air underwater and turned it back on. I had descended to approximately 23 meters when my wing inflator hose “popped” off when I started to add some air...

I'd still say that inverted tank/s aren't needed.

1) You have a buddy, who can provide assistance.
2) Disconnected LPI isn't a critical failure - you can oral inflate.
3) You can practise and master 'reach back' manipulation of your valve/s.
4) In the worst case, you could remove and replace kit to achieve the same result.

All of which are skill-based alternatives, that don't cost time, money or convenience.

Inverting a single-cylinder is an equipment-based solution that addresses problems that are either (1) rare and/or (2) easily rectifiable through more simple methods.

Granted, this happened because the connection wasn’t fully seated in the first place, but at that point I had a choice to make: either return to the surface or fix it where I was. After establishing neutral buoyancy manually, I tried several times to reconnect the hose, but with the line pressurized, it just wouldn’t lock

LPI disconnect/connect is an open-water course skill (when pressurised). If you couldn't reconnect the LPI then there's a bigger issue to be addressed; either a training deficiency and/or an equipment problem. I assume you rectified that problem following the incident and it hasn't repeated?

It's certainly not a problem that should repeat. Therefore, not a problem that needs addressing through expensive and inefficient modifications to the scuba configuration.

I got my dive buddy’s attention and he tried; still wouldn’t work. So, with his octopus standing by in case I needed it, I took a full inhale, reached back and shut off my air, reconnected the hose, and turned my air back on; all while drifting along in a mild current.

Off-topic, but I don't understand the reticence to utilise your buddies AAS as a first resort. I see a lot of divers exhibit this tendency. Is there some sort of stigma attached to using an AAS, even if temporarily? There shouldn't be....

In scuba training, we have students perform various drills without resort to using their buddies AAS (reg recovery etc). This is to ensure that they do have he 'bottom-line' capability of tolerating air depletion for a small timescale. It also provides further reinforcement for them to not hold their breath (blowing little bubbles). It's 'worst case scenario' training/preparation - but it doesn't mean that they should immediately resort to that worst case contingency in the future.

Twenty-five seconds without air, then the dive continued as planned.

I can think of more efficient and safe resolutions to that problem, but the end result was satisfactory. That said, I still cannot fathom why you would be unable to reconnect an LPI just because it was pressurised. I've seen a few LPI that were badly maintained...and had become sticky. However, that's a mechanical issue that isn't really effected by the pressurisation - they're a bitch to manipulate even on dry-land and without the air on.

If shutting off the air is the only thing that allowed you to reconnect, then the issue is beyond a 'sticky' connector.

No doubt, those of you who only dive with buddies will say that this would be a risky maneuver to try solo, and I agree. Still, for me it was a confidence-building experiment; I now know that if I have to do something like that myself, I can.

With respect to solo diving, then the diver concerned should have a redundant air source and the capability to problem solve and effect solution/s for any foreseeable contingencies. Shutting down gas is an option, because a redundant gas supply is accessible. In that respect, it is identical to buddy diving - where a redundant gas supply is accessible (buddies' AAS). A difference just exists in the fact that the solo diver would have to manipulate the valves themselves (reach back or kit removal) whereas a buddy team brings that immediate support - the buddy can do that for you.

Maybe it’s not a common occurrence, but I personally know of two other people who have lost their inflator hose connection while under water, and both returned to the surface.

Forgive my bluntness, but those individuals shouldn't have graduated from Open Water training. LPI disconnect/connect is a core skill that they should have 'mastered' in order to achieve their qualification.
 
That said, I still cannot fathom why you would be unable to reconnect an LPI just because it was pressurised. I've seen a few LPI that were badly maintained...and had become sticky. However, that's a mechanical issue that isn't really effected by the pressurisation - they're a bitch to manipulate even on dry-land and without the air on.

I find it harder in thick neoprene gloves, but without the gloves I might agree with you. With it unpressurized, I can first push it onto the stem, then hold the collar back as I push it all the way down. With it pressurized, I find it difficult to push it on far enough that I can hold the collar back without the hose popping back off. Again, this is in 5mm gloves with fingers that are cold; I don't have a problem with it in warmer water without gloves. I've always considered the disconnect the critical skill; you can take your time with the reconnect, or abort the dive.
 
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