Quad-Manifolds. Doable?

[dfuller299]

Hi everyone,

Fairly new to the board and finally OW certified. I wanted to jump in though and propose a question - one with a little bit of backstory though to make things clear.

When doing my OW checkouts, it was common for me to be fitted with Steel 80s. While they would work fine and give me tons of air, they are also well, huge on me as I'm barely 5'. I had been reading more into equipment that I wanted to purchase myself to move beyond the basics I grabbed from friends when doing my course (an 80s era 3/2 suit and yellow Cressi fins). It was this thought that, in combination with learning and doing a lot more diving that the idea came to me.

I had seen quite a few dual-tank manifolds online and even a couple at the local scuba store. The idea was since that giant tanks are huge on me, why not take a few smaller ones and put them together? The same idea as a dual manifold but with 20s or something very portable and "easier" to handle. I know people don't dive "for looks" but I was just thinking there has to be a more compact way. I'm not saying to dive on pony bottles. Obviously that's not recommended as that's for emergency use. But unless I'm understanding volume wrongly, four small or one large tank should give you roughly the same amount of air, right?

Now with that being put out there I want to state a few things:

1. I'm still a newbie. This idea, while something I do want to actively pursue is a side project along with wanting to learn more diving and start taking some advanced classes such as for photography. I'll still probably pick up my stuff at the local shop, do a ton of various dives with DMs I've met and befriended and all that first. This is just an extra idea.

2. While I'd like to think I very thoroughly think things through in planning and construction with mechanics, I'm not an engineer. I'm not sure how the manifold would be built without overpressuring the central bar. I made a couple rudimentary shoops of the concept but I'm not sure how well it'd work in reality. Would something like this even be doable?


3. Other members I've talked to about the idea privately have suggested I first learn more about diving. I wholly intend to do this of course and this manifold thing is not something I'm just looking to do in a year, or two, or three, even if it's "easy" to build. I like taking my time with the things I do to do them correctly and not be rushed. Not trying to cause any offense but I think it is easier to look at a crazy idea and think of it as being insensible and not approached with a calm and collective "let's make this work" demeanor. At the moment I'm just not seeing anything out there designed for us smaller people and wanted to present a concept.

4. I've yet to work out my breathing rate but at the moment I'm certified for (40' so far), I suppose again it is a question of how much air and bottom time I'd like (like anyone, a lot), and how deep I want to learn how to go. The thread explaining that there is plenty even within 40' of depth to view when you're in the right places is intriguing.

For this concept I would envision diving no deeper than 40' anyway; perhaps even less if the water was ideal.

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Thanks again to anyone having insight to post replies. Like everyone else, we all start new and I know I still have plenty to learn.

 

[EastEndDiver]

What no J valve?

 

[syntaxerrorsix]

Wow.

Ok so where do you clip off the 4th second stage again?

Why not just try a steel 72 if the steel 80 is to big?

Heck I'll give you one if you promise to delete that horrid spare air monstrosity

 

[Brewone0to]

It seems as though you have searched and
likely found a suitable solution to a non existent problem.

If you find that standard tanks are too tall for you,
try to locate an aluminum 63 cu ft tank.
These are shorter which may solve your issue.

Being a shorter/smaller than average person you likely also have smaller lungs.
Therefore,10 cu ft less than the 74-77 cu ft actually in an AL80 should be ok for you.

 

[bl6394]

Well.

Not sure how many o-rings this contraption would have, but it seems like it would have an amazing number of failure modes... Not sure whether I like the isolator design with 4 indepenent regs - or if he's better off with a single reg on a manifold that can't isolated. I wonder what sort of bands will make this whole contraption a rigid unit - and how to attach it to a BP / W - or better yet a nice jacket BCD...

rofl.

Seriously - my son is under 5 feet - and does great on an AL 63. I think you'll like that solution a whole lot better.

 

[MaxBottomtime]

Aluminum 50 Tank discounts on sale Catalina

If you think a steel 80 was cumbersome, four tanks and regs will drive you mad. Try an aluminum 50, 63 or a steel 72.

 

[g1138]

Wait till you go on vacation and get an Al 80.

If a St 80 is too big on you, the only options I see that will be shorter are HP 100, Al 63, Al 50, and possibly an HP 80. The only problem is that HP's are pretty heavy, and the Al's are pretty low volume if you ever want to take on dives below 60ft.
You could do dives to 80ft with an Al 50, but it would be a touch and go dive if you wanted to keep a safe reserve for your ascent. I usually get 18mins of total dive time when I'm with deep dive classes and all we have for the TA's are Al 50's.

As for your contraption I don't see how it would work. How would you mount it on anything but a Bp/W? Even with a Bp/W there will be mounting problems. You'll also have a pretty wide profile with those tanks, and I'm pretty sure you won't be as stable, it'll feel like you're a teeter totter during your dive.

Three tanks on the other hand maybe. I remember seeing a three tank contraption in one of Jacques Cousteau's videos.

 

[herman]

Triple tanks were used in the early days when larger single tanks were not available like they are today. Unless you have a need for a lot more gas (and that will require larger tanks) doubling or tripling buys you little in weight reduction. Shorter HP 80s would be a better choice. Now there is a huge cool factor to triples but it comes at a big price. Not only are the tanks and mainifolds expensive but the yearly (and 5 yr) cost to keep the tanks inspected is considerable. That said, I just got a vintage set of double 38's, not a lot of gas but they are cool....can't wait to get them in the water....oh and if you really want a set of triple 30s shoot me a PM.. I have a set.

 

[Bob DBF]

If the weight is the problem, you will find when trying to manifold multiple tanks togather the rig will be weighing more than a single tank of the same volume. As an example 4 - 19 cuft tanks weigh about the same as an 80, now add in the weght of a yet undesigned manifold, bands, and hardware to mount it on a BP/W. I'm figuring it will also probably be around 10" wider than a set of doubles. This tank length would probably have the wing taco fore and aft. It isn't that I'm against doing it or would turn down a chance to dive it, I just don't see it being practical.

If the length is the problem look for a shorter tank.

If both, get a smaller tank. I'd take the deal from synaxerrorsix in a heartbeat.

For your tank research:
http://www.huronscuba.com/equipment/scubaCylinderSpecification.html


Bob
------------------------------------------------
I may be old, but I’m not dead yet.

 

[dfuller299]

Thanks for the replies everyone. The 50s sound neat and may be a good compromise between having enough air and being "big enough". I'll look over everything a few times though again for sure. Again like I said, the 4-tank idea was just a conceptual thing. I doubt it'd look like that anyway but I'm not sure how else to illustrate it. 3 tanks might work but again will have to think about it. Thanks.

Obviously points of failure are wanted to a minimum but I can figure that multiple tanks present an issue there.