Newbie question: 60 vs 80 tank

[scubagirl95]

Hello,

Sorry for the newbie question, but what is the difference between a 60 and an 80 size tank? If I understand correctly, both can have 3000 psi.

When I certified, I used a 60. Then later on a dive with a co-worker, we used 80s. He is a 6 foot male. I am a 5 foot 4 inch female. I'm thinking I should stick with the 60, but I'm not sure why.

Thanks!
Lori

 

[The Kraken]

The 80 tank holds 33% more breathing gas than the 60 cu. ft. tank.

 

[sb_diver]

The 80 and 60 refer to the amount of air the tanks hold at 3000 PSI. You're right they both hold 3000 PSI but since the 80 is larger it holds more air at the same pressure( 80 cubic feet) Some females like the 60.. I think its actually 63 cubic feet but close enough.. because it is shorter and since they sometimes have better air consumption than a larger male can stay down just as long with the smaller tank than the big guy w/ the big tank. Use whatever works for you.

 

[The Kraken]

OK, that was a smart butt answer . . . I'll try to answer in more pragmatic terms.

Let's take a dive of 60 feet on normal air for 40 minutes.
Let us assume you have a surface air consumption rate of .5 cf/min.
A dive at that depth would require 56.4 cubic feet of breathing gas.
Using a 60 cu. ft. tank, you wouldn't have enough gas left to do a SAFE ascent and safety stop. Using an 80 cu. ft. tank you would have no problem.

 

[sb_diver]

I forgot another advantage of the 63 is its length. I know for some shorter divers the 80 is a little long. Kraken is right about the bottom time limitation, its a smaller tank so you'll have to plan your dives with that in mind. It depends what you're diving. A 63 would probably be fine for a shallow beach dive, but if you're diving deeper or longer you'll want a bigger tank

 

[scubagirl95]

Thanks, guys! That is a big help. I've been pretty good with air consumption and haven't gone down below 50 feet or over 40 minutes. The 60AL was more comfortable, so I think I'll continue with it until I want to go deeper and longer (probably another 10-15 dives).

 

[mweitz]

Scubagirl,

You may also want to look at the steel 80's. They are fairly short. My wife is 5'4 or 5'2 (I can never remember) and they fit her frame perfectly. I know some smaller people who can get two dives out of a steel 80 ...

I'm in Monterey a lot. If you want to try one, shoot me a PM.

Mark

 

[bcsean]

the steel 80 from PST is actually even smaller then a standard AL63. Great tank for smaller people.

 

[pasley]

Think quart and pint jars. Both can be presurrized to the same preressure, but one is larger and therefore holds more. The 63 holds 63 Cubic feetof air at 3000 PSI, the 80 hold 80 cubic feet of air at the same pressure (really 77) because it is a larger vessel.

 

[Mo2vation]

Thanks, guys! That is a big help. I've been pretty good with air consumption and haven't gone down below 50 feet or over 40 minutes. The 60AL was more comfortable, so I think I'll continue with it until I want to go deeper and longer (probably another 10-15 dives).

You're in NoCal, right? So Cold water. likely 7mm wetsuit at present. Maybe one day, a drysuit?

If you're really going to invest in a cylinder, chances are its going to be a substantial investment - like a steel tank.

If that's the case, I recommend the largest tank you can comfortably carry. Right now, that may be the 60. But soon, it will likely be an 80 or 100.

There are many, many ladies in the 5'3 - 5'5 range that dive 100's. I'm not a big guy (5-7 160-ish) and I went right to the E8-130 (from the PST 100.) It was a big jump, and I did a face plant the first few dives, but I've never once regretted having all that gas and the longer bottom time and increased peace-of-mind it delivers.

Its just a thought - but fast forward, think about it, and consider if you wouldn't like the 80 or even 100. My wife just moved from the 80 to the 100 with no issues at all. She's taller than you are, but like I said - there are plenty of smaller ladies managing 100's (and even the 130's...)

K