18 Liters Tank

[vixtor]

Well, I am sure I want steel - i would rather like the tank to be negatively buoyant at the end of the dive.

As for bottom time - a longer dive (as long as cold and depth allow it) is always nicer from my point of view - so that's why "bigger" sounds like "better" in my mind. I leave at about 260km from the seaside, so I like to benefit as much as possible from each trip.

at the risk of starting a religious war you might want to consider aluminium if you're going to doubles, just since it gets so heavy

 

[Jimmer]

at the risk of starting a religious war you might want to consider aluminium if you're going to doubles, just since it gets so heavy

Actually compared to high pressure steel, aluminum tanks aren't any lighter for a given capacity, but they are more buoyant, meaning you need to add lead and you end up being heavier in total. Aside from that, I could be wrong, but I don't believe aluminum tanks are easy to find in Europe.

 

[pwl]

Actually compared to high pressure steel, aluminum tanks aren't any lighter for a given capacity, but they are more buoyant, meaning you need to add lead and you end up being heavier in total. Aside from that, I could be wrong, but I don't believe aluminum tanks are easy to find in Europe.

sorry - i should have been more precise - double steels are going to make you very much more negatively buoyant. i'm not a twins diver, so i haven't worked through it myself yet, but the impression i get is that with twins you tend to have more air at the end of your dives, offsetting the buoyancy somewhat, and having fairly negative tanks towards the end of the dive can be a nasty experience if Bad Things Happen.

like i said - lots of variables, and i haven't put twins into practice myself anyway.

as to availability: i can only speak for australia, where AL tanks are pretty common - i'm assuming pretty much any manufactured good available in australia is going to be readily available *somewhere* in europe

 

[pwl]

As for bottom time - a longer dive (as long as cold and depth allow it) is always nicer from my point of view - so that's why "bigger" sounds like "better" in my mind. I leave at about 260km from the seaside, so I like to benefit as much as possible from each trip.

fair enough. without understanding the conditions you want to dive in i can't advise as well as i might, but i'm still thinking given your general size (since it's quite close to me own) that such a massive tank may be overkill & cause some difficulty, especially on exit.

 

[TheTrickster]

I'm 171cm and 66kgs and I find 15ltrs a bit over whelming! - I've used an 18ltr and its not a nice size...think a steel 15ltr in height, but 'fatter'....I have a 10ltr twinset, which is more comfortable to wear...

On a 10ltr I can normally get a 60min dive - only going to a 12ltr if I'm going deeper- I would seriously rethink the 18ltr - where you rent cylinders - don't they have 15ltrs? Once you purchase your own, you have the additional cost of servicing etc...

 

[Tigerman]

Im 178 cm myself an I dont think id want to get an even bigger tank than my 15l 232 bar faber steel..
Its plenty big and heavy already..
At the same time, I wouldnt get a smaller one either

For the record, atleast in Norway and I think most of the rest of europe, 12 and 15l tanks at 200 or 232 bar is the most common tanks.
Most common valves around here is DIN.

 

[Colliam7]

at the risk of starting a religious war you might want to consider aluminium if you're going to doubles, just since it gets so heavy

Yes, a religious war!. Jihad! Die, scuba AL infidel. Ooops, sorry, wrong board. You make a reasonable point. Depending on the conditions - depth, exposure suit, normal weight requirements, etc., aluminum doubles might be a consideration compared to steel doubles. But, my read of Vixtor's question is that he is asking about diving singles (I could be wrong, of course). Based on the comments, I can easily relate to what he is looking for.

As for bottom time - a longer dive (as long as cold and depth allow it) is always nicer from my point of view - so that's why "bigger" sounds like "better" in my mind. I leave at about 260km from the seaside, so I like to benefit as much as possible from each trip.

I moved from AL80 to steel HP 120s for that very reason. I seldom approach NDL on a single tank, but I usually end the dive because of air consumption, so bigger is better for me. Assuming the tanks he refers to are the equivalent of the HP 130s, I find them also to be a delightful single tank. (As doubles they are, indeed, heavy (very) on land, but easy to dive in the water.) I have never had the experience where a heavy tank caused me to roll belly up, or even felt like it might occur, whether diving big heavy steel singles, AL80 doubles or big steel doubles (130s). I dive doubles more often than singles now, but have several regular budddies who dive single HP 130s, and LOVE them. There shouldn't be a question of DIN vs yoke, especially in Europe, should there? Why would someone go yoke to begin with?

 

[evil_xander]

Having had both the 15L and 18L next to each other for several months, I can only advise you with 15L, everything more then that - go with doubles. 18 L tank is just too big, a tad taller and fatter then the 15L.

Your decision, but I find that 15L is more then adequate for any recreational use plus you have a nice reserve of air also available there. I'm sure you can have it refilled for the 2nd or 3rd dive of the day somewhere, but 18L would IMO only get you in trouble as you'd think to break it into a two-dive one-fill option and face issues somewhere down the road with that approach.

I switched to a drysuit recently and my air consumption went up 30% (it should decrease as I get more proficient) but the 15L still suffices at the moment.