Change in buoyancy from 12l to 15l cylinder

[Storker]

I probably could make do with a 15L but I have heard they are uncomfortable and unstable.

But seriously, I'm a little curious as to what type of tank you're using. Volume (water volume or surface cubic feet, but since you guys use the latter I'd prefer the latter as that would reduce the risk of something being lost in translation) and pressure rating. Reason is, I have an impression that some American tanks are somewhat larger and perhaps a little over-engineered compared to what we see here on the right side of the pond. So any data point would help in determining whether I'm right or not.

Over here, I don't think you'll be able to buy a single tank larger than 15L unless you look really carefully, and younprobably have to special order. I've seen double 18s, but that's just insane. A double 12 is more than heavy enough IMO.

 

[Diving Dubai]

I already posted 1.96m, 118kg. That coupled with being a newish diver (under 100 dive) I use a lot of air. I probably could make do with a 15L but I have heard they are uncomfortable and unstable.

I'm 1.83m and 95kg, my cylinder of choice is a 15L Steel @232 bar. They are neither unstable (I can throw them on my BCD or my Wing) nor are they significantly heavier (3kg) than a steel 12 x 232

I originally used 15's because on my elevated gas consumption when I was a newer diver. However that's no longer the case. I still keep with my 15's (I have 10 of them) because our local diving is remote and somewhat challenging. On a normal 1hr dive I'll surface with 100,bar, but it's not unusual for mother nature to kick us in the slats and we're abandoning dives being on the surface after only 40 mins with 30bar. I prefer having contingency. Thats in addition to the Al 40 or 30's we all carry as "bailouts/ponies".

 

[ljpm]

But seriously, I'm a little curious as to what type of tank you're using. Volume (water volume or surface cubic feet, but since you guys use the latter I'd prefer the latter as that would reduce the risk of something being lost in translation) and pressure rating. Reason is, I have an impression that some American tanks are somewhat larger and perhaps a little over-engineered compared to what we see here on the right side of the pond. So any data point would help in determining whether I'm right or not.

Over here, I don't think you'll be able to buy a single tank larger than 15L unless you look really carefully, and younprobably have to special order. I've seen double 18s, but that's just insane. A double 12 is more than heavy enough IMO.

The tank is a FX 133DVB Faber (see second page of this thread). I actually picked them up used for $250 cdn each. Plus the guy through in 100 fills (fill cards). For the diving I do, and considering my poor sac rate, the tanks are still a little on the large size. I usually finish a dive with over 1000 psi. I have also noticed this is increasing. Not having to worry about being the one to call the dive when I am out of air has allowed me to relax and improve my air consumption. Using NitrOx I have yet to have a problem with going beyond my NDL. A buddy I was diving with only had air for a 2 boat charter and he did go into deco on the second dive (5 min. at 50') so I do have to be aware of the issue.

 

[Storker]

The tank is a FX 133DVB

So, I guess 133 cu.ft? And, according to my search, 3442 psi service pressure?

Hm. 133 cuf is 3766L. 3442psi is 237 bar. 3766/237=15.9. 3766/232=16.2. Your tank is neither a 15 nor a 17, it's a 16.

And, yet again according to my search, grey color? WTF, Fabers are supposed to be yellow!

 

[BlueTrin]

I already posted 1.96m, 118kg. That coupled with being a newish diver (under 100 dive) I use a lot of air. I probably could make do with a 15L but I have heard they are uncomfortable and unstable.

Haha sorry I didn’t realise it was your post earlier on.

I am only 1.90m and 95kg, but I don’t find the 15l so massively unbalanced as EireDiver said but that could be the fact that I am a newbie. (I’ll give his blanket statement the benefit of doubt)

 

[ljpm]

So, I guess 133 cu.ft? And, according to my search, 3442 psi service pressure?

Hm. 133 cuf is 3766L. 3442psi is 237 bar. 3766/237=15.9. 3766/232=16.2. Your tank is neither a 15 nor a 17, it's a 16.

And, yet again according to my search, grey color? WTF, Fabers are supposed to be yellow!

Actually, mine are white. Looks like the grey are replacing the white tanks over here. You also see why I was confused with the conversions. The table lists it as 17. I had found another site that listed a 15L as being 125 cuft.

High Pressure 133 Steel Tank

 

[ljpm]

Haha sorry I didn’t realise it was your post earlier on.

I am only 1.90m and 95kg, but I don’t find the 15l so massively unbalanced as EireDiver said but that could be the fact that I am a newbie. (I’ll give his blanket statement the benefit of doubt)

As pointed out a few times, there are many different 15L tanks. Check out the table on page 2 of this thread. There is a 15L and a 15.3L. One is short and round and the other long and thin. EireDiver seems to be talking about the short round one (117CuFt. / 15L).

 

[BlueTrin]

As pointed out a few times, there are many different 15L tanks. Check out the table on page 2 of this thread. There is a 15L and a 15.3L. One is short and round and the other long and thin. EireDiver seems to be talking about the short round one (117CuFt. / 15L).

I know that you can have 232bar and 300bar for 15l the 300bar is heavier. Is that what you are talking about or is there something else ?

You just have to read my location to know that I am talking about 15l steel. It is even in my first post:

Is there a rule of thumb about how much weight less you need to use if you equip a 15l stew vs 12l steel ?

It is obviously heavier but it is slightly bigger as well and will have more air meaning that you have even less weight when empty.

Regardless of what he is talking about, he likes to make blanket statements, it’s not the first time he does this

Edit: here is a lot of the Faber ones, apparently they have quite a lot of choice:

Faber Industrie: Faber Cylinders for Scuba Diving

Edit2: for some reason I really thought that there was a Faber 15l 300bar, my mistake.

 

[Storker]

for 15l the 300bar is heavier

It isn't "heavier". It's a bitch. Stay away.

 

[BlueTrin]

It isn't "heavier". It's a bitch. Stay away.

I don’t think I could get a 300bar fill anyway.

What’s the issue with the 300bar ?