Looking for an intro tank

[Sludge]

Not all HP tanks are 7/8 neck threads. All the newer ones are 3442 psi and standard 3/4 threads.

"HP" is a model. ALL of these have the skinny neck and are rated to 3500psi. Cylinders rated to 3442psi are "E-Series" or "X-Series," depending on the manufacturer. None of these have the skinny neck, and none of these carry the designation "HP."

ALL scuba cylinders are "high pressure."

[Red Hat Jef]

Don't bother with single tanks and H valves, not enough "air" to do anything with, trust me I went down that route, wasted precious money. Sidemount, only spend the money once

I think the OP said she can't go sidemount.

One time a long time ago I think I saw a debate on how far one could swim with a single tank versus doubles versus sidemount. As I recall, the consensus was that a single tank can get you quite a ways, in terms of bang for the buck. There are a fair number of dive sites (OW or otherwise) that have a long walk where I'd most certainly want a single. (Orange City Blue Spring, Buford, Troy...) Seems like a reasonable starting out setup to me, and the point of an H valve is that you can convert later, so the OP isn't "wasting money." You probably just didn't buy half of the set you wanted for sidemount first.

[Sludge]

I think the OP said he can't go sidemount.

With that screen name, I hope he's a she.

[Red Hat Jef]

With that screen name, I hope he's a she.

DOH. Apologies.

[a64pilot]

I believe it was NACD doesn't "do" sidemount, not she can't. but that is arguing semantics, I'll give you that.
1/6 of 85 cu ft is 14 correct, assume a SAC rate of .4, females don't use much air, at 66 ft I think air consumption would be 1.2 cu ft per min? Always forget , but I think the multiplication is by absolute pressure isn't it? Anyway that's 11.6 min. of gas, say 15 min as you don't start at 66 ft., but you do put in the line, swim through the cavern, so what maybe 8 to 10 min. in the cave? Or is my math screwy?

[hunabku]

Intro on singles dive thirds.

[a64pilot]

My mistake then, so in that case a single tanks has as much gas as doubles.
I did adv rec trimix in a singe 130 with an H valve as I can't "hump" doubles. Even a 130 isn't enough gas to really do anything with, so I have essentially everything that I used for that course that sits unused, I can do sidemount as it only requires me to "hump" one tank at a time and gives me plenty of gas. I still say if your getting into this kind of diving before you buy anything decide for sure what your going to end up doing if possible, and I don't think there is much future in single tank cave diving, I think it's a stepping stone and you may end up with a BC, hoses, H valve etc. that are unused, yes I know you can convert many backmount BC's , but maybe it's not as good as a purpose made BC?

[Pink Tank]

The main thing is that I'm not sure if I will ever go past intro diving. I currently have 2 aluminum 80s, but I figure it isnt worth getting an h valve put on one of those.
If I ever go sidemount, I assume I can use my AL80s for that. But for now, what else am I to do? And I hate renting tanks... I can't help but feel like I'm just throwing away money.

Just an FYI - on my intro dive, we got 800' back and I didn't yet hit my 1/3rds on an 85. I'd say my sac rate is pretty good.

[RN]

but NACD doesn't allow it yet.

NACD is BM only.

This is incorrect. I'm an NACD instructor and most of my students dive sidemount. I do this with full authorization from the training director. Granted, NACD does not allow all of its instructors to teach in sidemount, but those of us with sufficient experience and qualifications in sidemount can teach NACD cave courses in sidemount.

[gschaut]

For what it's worth, I'm in sidemount due to shoulder injuries. NSS-CDS allows sidemount at all levels of instruction, with instructors approval.

Unless you plan on staying Intro, and going no further, you're going to have to transition to side mount at some point.

Just saying...