Which tank to buy my wife- 80cf or 63cf?

[Mike Boswell]

By my reckoning, your wife uses about 80 percent as much air as you do (1600/2000=0.80) and a 63 cu. ft. tank has about 81 percent of the air in an 80 (63/77.4=0.81) so in theory the two of you would end a dive with the same amount of pressure in your tanks.

Her 63 tank would be about 6 lbs lighter and 4" shorter and this would be a plus for her.

With the same pressure in your tanks at the end of the dive, she would only have 80% as much air as you, but she only uses 80% as much, so normally that would be fine too.

Your rock bottom pressure will need to account for the smaller tank. You will want to plan for the possibility that you run out of air. She should have enough reserve in her tank to get you both to the surface.

 

[oceanbound]

i'm fairly small and love my AL63s. I prefer them to anything else. but I know that when I am traveling somewhere i can't take my tanks I know i normally will have 80's as rentals so long as it's a dive off a boat i'm fine. As for running out of air, my bottom time usually runs out before my air does in the Gulf. In the springs I can do a 60 minute dive depending on how deep we go. so don't fall into the trap of thinking she'll have less air. I'm usually my buddies "pondy bottle" if needed. but your wife needs to decide for herself. I am only 5'3". you said your wife was a few inches taller. she might prefer the 80s.

 

[aquaregia]

Quick math:
Your AL80/1000psi end-of-dive gives you 25cf reserve. Assuming you wanted to maintain that, you'd need to stop at either AL80/1000psi or AL63/1625psi.
In your scenario, you've used roughly 52cf of air and your wife has used 41cf of air. 41cf of air comes out to AL63/1034psi, which gives you only about two-thirds of the reserve gas that you had before.
So basically, if you're comfortable dropping your reserve, or cutting your dive time, you're golden.

 

[spectrum]

If the 63 for her matches your AL80 consumption then it sounds like the way to go. The more comfortable she is the more diving you will both do. If you up the ante with a 100 for yourself latter then she gets the 80. Better yet if you do become more locally active is HP steel.

Pete

 

[stargost]

Fourseventeen,

Try to test all the different version of tanks. I rushed and bought my wife a steel HP80, and it ended up being a mistake. I wanted to save her the weight compared to my HP100, but eventually, it is not really much saving, and the weight distribution and the fact these tanks are short end up not being the best solution.

Someone advised a LP72, and i may get one. So far, adoption of the HP100 has become the best choice when diving BP/W. With a BCD, the 80 is okkish, still not as good.

 

[deepstops]

I'm just throwing this out there, Hymark makes an AL72 that's very nice and myself, I'm a big fan of Faber LP85

 

[Graeme Tolton]

We can't tell you what to buy... have her try different tanks in the pool and find out what best suits her. You never know, your style of diving may change and you will want longer bottom times.. Deeper wrecks, etc... Think about what kind of diving you might want to do in 5 years and base your purchase on that. A few years ago, i scrapped my old luxfer 80's that no one will fill anymore and bought 2 new worthington hp119's. Dove them single for a couple years and found that they didn't give me enough gas for some of the dives I was doing... So, I got a manifold and bands.. Now I have plenty of gas all the time.. But I had planned on doubling them up when I bought them.

 

[halocline]

I far prefer AL63s to AL80s, just in terms of trim and carrying them around. If you can find a LP72 in decent shape, that's a nice tank to dive with, 26LBs carry weight which is about the same as the 63, and you'll have more gas than the 63. The buoyancy of the two tanks is pretty similar, LP72s are more or less neutral empty and I think 63s are about +2.

IMO AL80s have very little going for them except they're cheap.

 

[Fourseventeen]

Our LDS doesnt rent anything buy AL80's so shes never had the opportunity to try anything but that. They do sell both AL80 and AL63 as well as 3 sizes of steel. While I really like the steel tanks personally they are just to costly for what we are going to use them for. If I lived on the coast somewhere then I would def buy us both steel tanks and ditch the AL tanks. BUT since 90% of our diving is vacation diving and the other 10% of diving is either done in the local lake on a single tank dive (this lake there is NOTHING to see) or in our home pool just so we can keep brushing up on the important skills and our buddy signals. In reality these tanks will probably get filled maybe 20 times in a year. They wont get much use thus the reason I didnt want to go steel for these tanks. We ended up picking her up an AL80 Catalina tank this evening. She got black and wants to order the pink mesh tank protector and the pink boot for it lol.

 

[Angry Turtle]

.... I know she wants the 63 but I am leaning a bit more towards the 80 i think

It is HER tank, buy what she wants and you both will be MUCH happier.

Only present her with your opinion why she should go with one or the other.

My wife who is of similar build, dives with HP steel 80's and LOVES them.

Earlier this month in our Bonaire vacation the aluminum 63s where a second best, but VERY much prefered over the al 80s.