And you thought the HUB was a bad idea!

[Robert Phillips]

With a 3.8 cubic tank, that's a third of what most single tank divers use (well at least those that I dive with reguarly), and it would be difficult to find dive buddies who want to dive that way. But seriously, they say that it's a shallow water unit and not meant to go beyond 30 ft or so. That being said, even if I was doing 10 ft dives I wouldn't let anyone I know use it.

It's actually a 3.8 litre tank. There is an huge diffrence between litre's and cubic Ft. Some one correct me if I'm wrong, but I think 3.8 litres equals about 30 or so cubic Ft. although still not the equivalent of an aluminum 80 but enough gas to get you in trouble.

 

[Hoppy]

3.8 litres equals 0.134 cubic feet.

 

[miketsp]

Hoppy,
you and I both know that 3.8 litres = 0.134 cu ft but the gentleman above appears to be American and they like to think in other terms. You and I realistically think of the cylinder capacity empty but Americans are optimists and like to think of their cylinders full so what for us is an 11.1 litre Aluminium cylinder miraculously turns into 11.1 litres x 207 bar x 0.0353 = 81cu ft or an AL80 to round it off.
In the same way a 3.8 litre cylinder specified in the ad becomes 27.8cu ft, nearly the 30cu ft mentioned.
Humour them..

 

[The Kraken]

Yep, we like to think of cylinders being full because we, unlike the British, have yet to learn to breathe from an empty tank. Talking about gas management !!!!
Just kidding, guys!
Love the British sense of humor.

 

[Boogie711]

Actually Mike, an AL80 holds 77 cu ft, not 81. They get filled to 3000 psi, which is around 204 bar.

 

[rjchandler]

77 cu. ft of air and 11 litres of beer. Ain't life good?

 

[miketsp]

Actually Mike, an AL80 holds 77 cu ft, not 81. They get filled to 3000 psi, which is around 204 bar.

I agree this is what is in the table but the math does not agree. Lets run the figures both ways as a check:

Published -> Converted
Specs Specs
207bar wkg 3042.9psi
3000psi 204.0816bar
77.4cu ft 2192.014litres
2200.2litres 77.69068cu ft
11.11litres 0.392302cu ft
678cu in 11.11242litres
678cu in 0.392361cu ft

Now however we do the calc by Boyles Law either multiplying 0.392361 x 204.0816 or doing it in metric we never get less than 80.04cu ft.

So does Boyle's law no longer apply?
Are we entering the range of non-compressibility of air.
I remember something about this when I studied supersonic flight some 30 years ago but I no longer have access to those texts to jog my memory.
Anybody care to answer?

 

[geraldp]

Hoppy,
you and I both know that 3.8 litres = 0.134 cu ft but the gentleman above appears to be American and they like to think in other terms. You and I realistically think of the cylinder capacity empty but Americans are optimists and like to think of their cylinders full so what for us is an 11.1 litre Aluminium cylinder miraculously turns into 11.1 litres x 207 bar x 0.0353 = 81cu ft or an AL80 to round it off.
In the same way a 3.8 litre cylinder specified in the ad becomes 27.8cu ft, nearly the 30cu ft mentioned.
Humour them..

Excuse me? What's this "Aluminium" you're talking about?

Besides... it was the brits that brought us cu. ft. in the first place and then they go and switch to liters (or is that litres?).

 

[miketsp]

Excuse me? What's this "Aluminium" you're talking about?

Besides... it was the brits that brought us cu. ft. in the first place and then they go and switch to liters (or is that litres?).

Useless piece of information (according to Google)
There are 8.920.000 web pages containing "aluminum" and 5.470.000 web pages containing "aluminium".
There are 1.570.000 pages with "litre" and 4.050.000 with "liter".

 

[bcsean]

Damn, there are just some things that don't really need to be simplified.

Maybe next they'll invent a suit with integrated mask and fins?