inverted manifolded twins

[fire_diver]

1- Cannot hear your valves. OK, give you that.
2- Cannot see your buddy while solving entanglement or gas issues. If your buddy is behind you, you can.
3- Cannot rent doubles setup for this configuration from most shops. cant rent double from most shops anyway
4- Additional unneeded cages for the valves. Unneeded can be said for ANY gear.
5- Whacky hose lengths. Can be said for 7 foot hoses in cave diving too.
6- Stage/Deco bottles block access to the valves. OK, thats 2
7- Cannot reach isolator. Do you know? have you ever tried it?
8- It looks silly. All diving gear looks silly.

Just playing devils advocate here... But I only see 2 valid points.

 

[elan]

The myriad of pretty big negatives are fairly well described...

The benefits of inverting:
smack the ceiling as hard as you want
reach the left and right posts quite easily (although this gets more complicated with multiple deco bottles on and suit inflation bottles)

You got more? I can't think of any?

btw UK cave/sump divers are not using inverted tanks. It seems that only UK wreck crowd still does. What about north sea ocean divers makes inverting "optimal"?

just add as a benefit: easier trim management. i.e. a tall person can used shorter tanks. The most heavy part of the system (manifolds with the regs) is closer to the most buoyant part: butt, upper legs, waist

But it potentially presents a problem with long tanks as the manifold can be quite far down

 

[elan]

You say ease of access except for multiple deco/stage/inflation bottles but what if the diver doesn't carry them. You can't assess every configuration as good or bad based solely on how you, in particular, might dive. Or I guess you can but your assessment would then have to be considered narrow in scope.

The beauty of the DIR/GUE/UTD configuration is the you can start to learn the configuration when you do not carry the bottles and then smoothly transition to advanced diving when you need to and your skills will not be invalidated. So if you get muscle memory working at the beginners level you can use them at the higher level

At the end it is for the diver to decide whether he wants to use the existing adapted system or "invent" something new , of you dive not well known configuration you run into the risk of other people not being familiar with it. Whether one wants to take the risk and whether it is worth it is one's own business. If I had two factors; 1st learning to reach the valves with upright config and 2nd switching to not so well known config with downwards tanks I would push myself a bit and learn the procedures of reaching the valves. Reaching the valves in upward config is very easy and one should really have great limitations in shoulder movements not to be able to do that. I would say if you can lift your arm parallel to the floor it's all you need to be able to reach the valves if done properly.

 

[rjack321]

just add as a benefit: easier trim management. i.e. a tall person can used shorter tanks. The most heavy part of the system (manifolds with the regs) is closer to the most buoyant part: butt, upper legs, waist

But it potentially presents a problem with long tanks as the manifold can be quite far down

Ok I'll give you that one. On anything but really tall hp120s it might actually suit some folks better.

 

[DaleC]

The beauty of the DIR/GUE/UTD configuration is the you can start to learn the configuration when you do not carry the bottles and then smoothly transition to advanced diving when you need to and your skills will not be invalidated. So if you get muscle memory working at the beginners level you can use them at the higher level

I also like that configuration and see many benefits to it (and use it for more serious diving myself sans isolating manifold) but I also see the problem with subscribing to it (the regime) dogmatically - you are not encouraged to explore other options (as can be noted in this and many similar threads). For me, recognising the validity of one system does not invalidate the other.
It should also be noted that not everybody is going to progress to carrying multiple stage/deco bottles or use argon for their DS. All roads do not lead to the WKPP. The skills one needs to learn are the ones that apply to ones situation. Learning a set of skills because someone else thinks they are optimal for "their" setting isn't always actually optimal. I know that is heresy in some peoples minds but its not in mine. Someone who learns and plans to dive inverted tanks will not have their skills invalidated if they dive that system. I also don't subscribe to the law of primacy or even muscle memory so much for that matter as I dive several very different rigs. My focus is mainly concentrated in adaptability.

At the end it is for the diver to decide whether he wants to use the existing adapted system or "invent" something new

That's the funny part-inverted tanks are not being "invented". In fact, upright, iso/manifolded tanks are the new kids on the block chronologically speaking.

of you dive not well known configuration you run into the risk of other people not being familiar with it. Whether one wants to take the risk and whether it is worth it is one's own business.

at one time the "DIR" approach was the not so well known system - I'll leave it up to others to decide if it was worth it or not. I also dive with an assortement of divers with many different rigs so again, the skill of adaptability is more important to me than relying on standardization. And yes, I know other divers will have different priorities

If I had two factors; 1st learning to reach the valves with upright config and 2nd switching to not so well known config with downwards tanks I would push myself a bit and learn the procedures of reaching the valves. Reaching the valves in upward config is very easy and one should really have great limitations in shoulder movements not to be able to do that. I would say if you can lift your arm parallel to the floor it's all you need to be able to reach the valves if done properly.

Just to be clear, I'm not encouraging anyone to use any system just discussing it for its own sake; but you are doing that thing again: starting off on the premise that one system is established (standard) and the other is unknown. That only applies really in N.A. In some parts of Europe inverted tanks are not uncommon. To make your case more accurately you would have to base your decision about the valves on what was actually easier. Unless you've tried both ways you can't really say which is which.

 

[rjack321]

That's the funny part-inverted tanks are not being "invented". In fact, upright, iso/manifolded tanks are the new kids on the block chronologically speaking.
.

Umm yeah, since the Benjamin manifold was invented in the 1960s, that's 50yrs ago. Yeah some of the earliest maniolds were single outlet, but those were still right side up (with J valve no less). Then the dual outlet came along and it was still valve up. Then the isolation manifold came along - still valves up. Finally late in the evolution of manifolds some folks decided to turn the tanks upside down - something which has since fallen out of favor just about everywhere except the North Sea and even there its more and more unusual.

So Dale are you going to come up with some pluses for inverted doubles or not?

So far those of us not diving them have a whopping 3 pluses:

• tanks bottoms don't care about ceilings
• easy to reach left and right post if you are only wearing the doubles
• possibly better trim for some folks if the tanks aren't too long

The negatives are scattered below this is about their benefits.

You seem compelled to defend a configuration which has extremely limited utility and lots of contortions IMHO. I'm not diving them because they don't make sense to me. If they make sense to you, tell us under what circumstances and why please.

 

[DaleC]

I'm not defending, I'm analyzing; there is a difference. And at least I have the good graces to say that, because I haven't dived the configuration personally, I don't have all the answers to some of the issues posed. That's why I analyze - because I like to understand. Some issues I can see as valid, some are questionable because I don't have all the info and some I can see are non sequitirs. I don't just hold things in contempt before I investigate. I also don't minimalize the experiences of military and European divers just because I don't dive their way (or they mine).

I'm comfortable saying I don't know.

As for the early forms of inverted doubles (and triples and quadruples). Often the regulator valve was upright because they were using doublehose regs but the valve(s) that they intended to manipulate during the dive were valve down. Here are a couple of pics from prior to late in the evolutionary process:

I have a lot of early photos in old books that show single tank inverted diving from the 1950's as well that I can scan too - but not tonight. I have to go watch a movie.

 

[Slamfire]

If rjack was at the Tacoma Dive Show he probably saw these first hand. It looks like those tanks have a helicoidal welded seam as well as an end cap welded seam. That would mean they're not drawn from a slug, but rolled and welded from sheet metal. Do you know the pressure rating on these?

 

[PfcAJ]

Originally Posted by ucfdiver
1- Cannot hear your valves. OK, give you that.
2- Cannot see your buddy while solving entanglement or gas issues. If your buddy is behind you, you can.
3- Cannot rent doubles setup for this configuration from most shops. cant rent double from most shops anyway
4- Additional unneeded cages for the valves. Unneeded can be said for ANY gear.
5- Whacky hose lengths. Can be said for 7 foot hoses in cave diving too.
6- Stage/Deco bottles block access to the valves. OK, thats 2
7- Cannot reach isolator. Do you know? have you ever tried it?
8- It looks silly. All diving gear looks silly.

Just playing devils advocate here... But I only see 2 valid points.

Point number two. Think this through for a minute, Fire Diver. If my valve/reg is leaking, I can face my buddy while we work out the problems if the tanks are valve up. If they are valve down, that can't happen...

Point 5- 7ft hose in cave diving is the norm because its all you need, and nothing you don't. They are easy to source in shops and online. Why should a diver have to be ALL custom length hoses when the proper lengths are easy to find?

 

[fire_diver]

I can still face my buddy while I reach behind my back to turn a valve. I do it every day in my job. It's also very easy to reach back to turn a valve.

How "common" were 7 foot hoses when HOG configs were new? Everything "new" is custom at some point. Then at some point those custom items become common. Look at how long it took for backplates (real ones, not those cheap-ass plastic ones form the 70s) to become mainstream.