Tank sizes, suggestions?

[mancub]

Forgive me if this is redundant, I am trying to catch up on reading posts here, but didn't want to dig too deep into the past. I suppose redundancy is great for divers...heh

I am a new diver (sub 100 logged) and currently dive a single steel 80. My dive buddy does the same, in fact we have very similar rigs...dive fair. We both completed our advanced open water within a few months of starting, and over the past year have dove a fair share of 80-100fsw dives. Both of us are distance runners, and don't have terrible air consumption (always trying to get better), I'd say pretty decent for beginners. Anyway, we dive conservatively, often in thirds, within NDLs and keep a close eye on psi. I agree with the other posts, that often I am conscious of my air and have plenty to get me back to the surface, but if my buddy were to run out, we might be a little pressed for ending the dive with extra air. As a greater number of our dives are between 80-100fsw, it seems only smart to think about either bigger tanks or possibly additional/redundant supplies.

I am 5'8", skinny asian guy, so the steel 80 I lug around now fits great. Not too long or too heavy. I don't think the twenty breaths from a spare air are worth it... maybe on a tropical vacation...and have only thought about pony bottles as a redundant system. seems the 30cu ft are just about the smallest that are worth it when diving around 100fsw. But recently reading around on here, the idea of doubles came up. Never thought of that, seems a bit advanced but maybe another alternative to a pony bottle? I don't know much about how you run twin tanks... breathing from both all the time, or one at a time switching back and forth?

We have been content diving single tank rigs, and probably will for the next bit. Maybe we want to think about getting bigger tanks for our deeper dives, and using our 80s on the second dive of the day, or a tank with EAN. Oh, we also got our EAN cert with our advanced, so maybe diving with nitrox more is another smart step. With our 80s we always turn the dive and stay within NDLs (We can go to 100fsw-briefly- for 40 minutes and end up with around 1000psi)...nitrox hasn't been worth the more expensive fills and tank rental. I am curious how other shorter and not hugely muscular people do with 100s and bigger? And...it is likely that we may upgrade to double tank rigs in the future, so... thoughts and suggestions. Thanks and happy diving.

[LCF]

I'm 5'4" and 120 lbs. My usual single tank setup is an LP95, which trims out nicely and isn't too heavy to handle at all. I can max out my NDLs at 100 feet on this tank. But I've also dived a HP130, which trims out almost identically. That's a mad amount of gas in a single tank (and they're handy for transfilling doubles if you go there, too!)

For doubles, I've dived LP72s, which don't balance well for me. I currently dive LP85s, which I love, and which give me enough gas for two deeper or longer dives, or three of my usual recreational cruises. I've also played with a set of Al80's, which have been fun in warmer water, but I cringe at the thought of the weight I'd need to sink them in the Sound.

Doubles are really nice to dive, but they are a PITA to schlep around on land, and some charters aren't real happy about them (don't fit in tank racks).

[Joshua Smith]

You need some training to dive doubles safely, or at least some help from someone experienced with them. Many people transition to them when they take their first tech class, such as advanced nitrox/ deco. But you shouldn't HAVE to take a tech class to learn how to dive them safely. I'd recomend the pony bottle for starters. 30 cf is good, but I think 40 is better- they're very close to the same size, and you get 10 more cf. You can mount it on your tank, which I tried, and hated. Although I know some excellent divers who do just that; it just didn't work for me. I tried slinging mine on my left side, and loved it- I hardly even notice it's there, once I'm in the water.
The really important thing, if you go with a pony (Stage bottle) is that you practice deploying it and breathing out of it regularly. If you ever really need it, you don't want to suddenly discover a problem you hadn't previously anticipated with it!

[CaptnJack]

I'm your size and dove LP95s for years. Its a little hard to compare because you don't really give any details of you dive profiles or SAC rate though.

Before actually buying other tanks I'd recommend Grateful Diver's gas management class. Or GUE's DIRF. Both will teach you the basic information and inform your tank selection process.

[thelawgoddess]

i mostly dive HP80's and sometimes my AL80's when the HP's are empty. i got my boyfriend to buy a bunch of HP100's. we're close to matched in air consumption on tanks when i'm on HP80's and he's on HP100's. sometimes i dive the HP100's - i find they trim out easier than the HP80's, and i love the amount of gas i get. they are heavy but luckily around here there are so many dives to do where you don't need to walk that far. i get help standing up and putting my rig on and try to tread carefully so as not to hurt my back or pull anything.

there is a huge amount of money and training that goes into moving to doubles. it would probably be less costly and involved to learn to sling an AL40.

definitely get some gas management training if you can - you will learn how to determine the amount of gas you need to get both you and your buddy safely back to the surface. somewhere online there are worksheets you can download to help you do some of the calculations, but i can't remember where i've seen them ...

[mancub]

thanks for the speedy replies. I am actually overseas...so my logbook and laptop that have my dives downloaded to it are not near me...or I would attempt to give better dive profiles and SAC rate. I have already PMed back and forth with grateful diver a bit, and am planning on a gas management seminar. Should help a lot.

...never thought about swinging a pony bottle. Sounds less painful than another tank on my back.

Cheers, Jacob

[Sea of Green]

I am a new diver (sub 100 logged) and currently dive a single steel 80. ... completed advanced open water ... dove a fair share of 80-100fsw dives. ... don't have terrible air consumption ... dive conservatively, often in thirds, within NDLs and keep a close eye on psi. ... a greater number of our dives are between 80-100fsw, it seems only smart to think about either bigger tanks or possibly additional/redundant supplies.

I'm heavier than you are, but dive the same profiles. I switched to HP steel 102s and am glad I did. I get 45-1:00 out of a typical dive (80-100fsw) before I run low on air. By that time I'm usually getting chilled anyway. I carry a 13cuft pony for a redundant air source. I'm a firm believer in self-rescue and a totally redundant air source, I've never trusted an octo off the same first stage as the primary regulator. A buddy is good, but don't count on them. It's too easy to get separated in the limited vis we have in these waters. For your next cert, I highly urge you to take Rescue Diver. Best cert for the money.

[mancub]

Cool, I've been wanting to look into HP tanks. However, I have a yoke valve setup...would I have to switch to DIN? And do you mean 120s? or 102? Funny, I just emailed back and forth with my instructor, prolly taking rescue in September.

Thanks again for more info, if I don't respond for a while, it's because I won't have access to a computer until August 23rd or 24th. Cheers.

[thelawgoddess]

no; you don't *have* to switch to DIN ... but you might think about it.

some HP tanks have thermo DIN/K valves that have an insert for use with yoke regs, but DIN is a lot stronger and it wouldn't likely cost too terribly much to have your reg changed over ...

[CaptnJack]

True HP tanks (3500psi with a 7/8" neck size) will always have DIN valves. 3442psi HP tanks often have convertible 200 bar DIN to yoke valves. Assuming your regs yoke is rated to at least 3442 you can use it on these tanks (some older yokes are not adequate).

But as Lawgoddess said, DIN is a better connection and typically only costs about $65 to switch. A DIN to yoke converter (for traveling) costing about $35.

[Burntchef]

if you want i have a worthington hp100 you could try, let me know and we can hook up for a dive.

[Tangfish]

IF diving it as a single, get a LP tank my friend, you won't be sorry. LP 95/98s are a good way to go. Many of us use em, and affectionately call them "Berthas".

IF you're set on going the doubles route, then I might consider HPs, for the simple fact that they're smaller and perhaps easier to handle being a 5'8" skinny asian guy (I wouldn't know anything about that, but so I've heard).

I just love LP tanks because you can typically get a much better fill, unless either you're doing them yourself, or you have a really good, patient buddy at your LDS.

Here's a helpful chart to assist you in comparing tank pressures and capacities.

[thelawgoddess]

IF you're set on going the doubles route, then I might consider HPs, for the simple fact that they're smaller and perhaps easier to handle being a 5'8" skinny asian guy (I wouldn't know anything about that, but so I've heard).

in case you've never met calvin, his last (parenthetical) statement carries a bit of irony with it. :-)

[Sea of Green]

Cool, I've been wanting to look into HP tanks. However, I have a yoke valve setup...would I have to switch to DIN? And do you mean 120s? or 102? Funny, I just emailed back and forth with my instructor, prolly taking rescue in September.

Thanks again for more info, if I don't respond for a while, it's because I won't have access to a computer until August 23rd or 24th. Cheers.

I meant 102's. Most people refer to them as "100s" but technically the hold 102cuft of air. 120s would be too hard on my back and not needed for the type of diving I do. I like these tanks because they are the same size as the Al 80s I used to use, but hold more air and aren't terribly buoyant when empty.