I'm just starting, so I don't know much...are these steel tanks? Are all steel tanks shorter than AL80s?
Yes, those are steel tanks.
No, not
all steel tanks are shorter than AL80's. However, the HP80 that was mentioned is shorter.
It just occurred to me that the nomenclature for tanks is a bit odd. Generally there are:
HPxx = High pressure tank made of steel
LPxx = Low pressure tank made of steel
ALxx = Aluminum tank. (High/Low pressure isn't relevant here as far as I know)
where xx is a number representing the size in cubic feet of the tank.
So, AL80 = Aluminum tank that holds 80 cubic feet of air. HP80 = Steel tank that holds 80 cubic feet of air. These tanks are different sizes/weights due to the different metal. They hold the same amount of air. Many steel tanks are actually bigger than AL80.
AL63 only holds 63 cubic feet of air. Less air than al80, but smaller tank than AL80. It costs less than an HP80, and is more likely to be available for rental at dive destinations than HP80.
Al80 is by far the most common tank in the world. They're a lot cheaper than steel tanks, and are ideal for most (but not all) divers doing single tank recreational dives. You'll find these tanks everywhere you go. In some places you'll find others, but not always.
As others have mentioned, most women have a big advantage over men when it comes to diving. Women tend to use less air. I know there's a hot air joke about us men coming shortly
. That means you might be just fine with that al63 as others have said. One of my female dive buddies seems to breathe gas at about half the rate I do. My wife breathes at about the same rate as me. It will take you some time to see where you fall in terms of air use. Also as you get more comfortable with diving in general, your gas use will decrease.