Fisher-Price my first stage bottles, what do you use?

Hi there, I am going to be take Advanced Nitrox and Decompression procedures in May here in the New Jersey. I was wondering what size/type bottles did you start with? I hope my instructor will help me make that decision. However, thier recommendation will have a New Jersey Wreck diving perspective. I am currently an intro diver and am planning to continue onto full cave once my instructor says I am ready and I agree with him. :)

I spoke to a trusted friend tonight and his instructor directed him to 50cuft lp steel tanks. He said they are easy to get filled to the right blend without needing a lot of pressure in the bank and they have agreable bouyance characteristics. Do you agree?

Thanks in advance,
Hans

My personal preference for staging and decompression are aluminum 80's.

I am going to have to agree with the Cap'n...My preference is to stay away from steel bottles for stage and deco...AL 72s are pretty damn sweet....

Assuming the standard dives that are done in saltwater with short bottom times and reasonably short deco times I see no reason to use 72s or 80s for the 18-20minute deco times on a 70' stage bottle or the maximun 25minute times on O2. These can easily be done with AL40s, and they are sweet in the water.

Naturally if you start doing 250' dives with bottomtimes much over 25 minutes, you will need other (larger) decotanks and much bigger backgas tanks.

Michael

For stage bottles AL80s always.

Sometimes for deco S72s are nice for cause they stay on the bottom, have a lot of gas and don't float even when empty but AL40s are generally more convienient. Especially off of boats deco bottles of preference are AL40s because you have to lift them on and off the boat without getting killed or bending yourself. Often you may be carrying your deco bottles with you the whole dive and 40s are almost unnoticable compared to 80s.

Those steel 50s are a nice blend of characteristics - and hold a little more then AL40 when you need that little extra. Generally preferable to a 72 but AL80s are still better for stage diving. They cost a lot more then AL40s I think but rarely will you see all that much benefit compared to AL40s.

If you were getting 2 bottles for extended staged deco (for like Trimix) I'd might get either 2 AL40s or one AL40 and one S50. Since I have a S72 around the house for the rare occasions where a little extra is needed I'd rather have two AL40s - and a AL 80 often works well for that also.

For short decompression times, I do like to use aluminum 50's because of their small size and light weight.

Not sure if you caught I was talking about AL 72s not STEEL 72s. I was talking about AL 72s. They carry about the same amount of gas (AL 80 = 78 ft3 @ 3000# / AL 72 = 72 ft3 @ 3000#) and they are a smaller diameter tank.

AL 72s make GREAT stage bottles.

For what you are doing now, an AL 40 for 100% O2 will be perfect. It can also be used for deco when you are taking Apprentice and Full-Cave. So, you'd knock out 2 birds with one stone. This smaller bottle would be good for wreck too, I'd think, since you're keeping it with you the entire dive. I'd stay away from steel tanks of any kind when talking stage/deco bottles.

If you think you need a second deco bottle for deeper stops before you switch to 100%, then get an AL 80 filled with 32% nitrox. This stage bottle can be used for staged decompression on deep dives OR can serve you in single stage cave dives once you are full-cave. Again, you knock out 2 birds with one stone.

Bottom line, always look at what you might be doing in the future when making purchase decisions today. It will save you a LOT of money in the long run. You don't want to buy Fisher-Price now and then later have to buy bigger boy toys.

Another consideration down the road - I also have an AL 80 100% O2 bottle for really deep dives where the long 20 and 10 ft stops will require more O2 than an AL 40 can provide (given required reserves). I also have an AL 40 50% bottle used for 70 ft. If I use a 70 ft bottle, then I don't use the 32% bottle, and visa versa. So it gives me a little flexibility in dive planning.

For my O2 I use an Al40, for all my other deco gases I use Al72s (32% and 50% currently).

AL80s are good stages and can be used for deep deco gas as well. They ride reasonably well - their only problem is size.

AL40s are the "standard" for deco bottles in many cases, and make great 70' (50%) and O2 (100%) bottles.

If you dive in the ocean where you do not drop bottles then you do not want steel stage/deco cylinders. They will drive you nuts with how they ride. Aluminum 40s and 80s are the way to go if you do that sort of diving at all. For deco cylinders in a cave where you're going to drop your oxygen close to the entrance how the bottle rides becomes much less important, since you only carry it to the drop point a small distance into the cave.

For cave only you may want to consider a steel 46 for O2. They are NOT ideal for the ocean, but work well in caves, where you are going to drop the bottle near the entrance. The nice thing about them is that you can get a nearly-full fill off a transfill without having a booster. Their effective capacity is much larger than an AL40 for the booster-impaired diver for this reason. This is a specialized application.

IMHO 100% bottles should never be used for anything else. Stencil them with paint and dedicate them. This greatly reduces the risk of contamination and accidents, and is well worth it. My 100% bottles are never used for anything else.

Ditto for my 70' bottles. Those too are dedicated.

My AL80 stage/deco bottles are used for various mixes (and appropriately labelled) but never see high FO2 gas. They ARE O2 clean for PP mixing though.

If you need an 80 for O2 at 20' you're doing some major mondo decompression - I'm not there yet in my diving where I can't do my O2 time on a 40 or 46. A 40 lasts a good long while at 20'.

No reason to have any o2 bottle that will last more than 30 or 40 mins unless you want to use it on multiple dives. Remember, at 20' the longest you can breath o2 is 45 mins anyway and I think most people would start getting nervous before that.

Quote:

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Originally Posted by looseBits

No reason to have any o2 bottle that will last more than 30 or 40 mins unless you want to use it on multiple dives. Remember, at 20' the longest you can breath o2 is 45 mins anyway and I think most people would start getting nervous before that.

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Yeah, I use mine for multiple dives if I don't want to have to refill or can't. But Sunday, I was on 100% in Eagles Nest for 45 minutes. Granted, some of that was at 10 ft. It's interesting to see on a dive deco planner how ascending to 10 ft will cut some of that O2 exposure but not significantly affect the deco time.

Originally planned to use the bottle the next day for a similar dive, but the dive didn't make. Plus, my AL 40 I left at home wasn't completely full.

But, truth be known. If you did do a dive where it required 45 minutes at 20 ft (barring a 10 ft stop in this example) on O2 and you assumed a .4 SAC rate, the required O2 would be 29 cf. Add a third for reserve and you'd need 44 cf. Easier to just overfill it, assuming you can.

Quote:

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Originally Posted by looseBits

No reason to have any o2 bottle that will last more than 30 or 40 mins unless you want to use it on multiple dives. Remember, at 20' the longest you can breath o2 is 45 mins anyway and I think most people would start getting nervous before that.

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I don't agree with this principle at all...
What if your buddy needs your O2...lost bottle/malfunctioning reg.
What if you get bent and need suface oxygen.
What if your bottom time runs long and you have more deco.
OTC units are theoretical at best and you can take breaks to minimize complications of prolong oyxgen exposure.
I always try to have at least twice the amount of oxygen that I expect to need on a dive.
I use steel 72's, 30's and even an old lp 50(2015psi) for oxygen. I prefer the low pressure steel tank's fill ratings and boyancy characteristics.
I find that the more modern steel 45's are bit too negative. The aluminum 40's and 80's can make for adequate O2 bottles except for their 3000psi fills to capacity and their excessive positive bouyancy when near empty.
Safe diving,
Lee

Quote:

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Originally Posted by looseBits

No reason to have any o2 bottle that will last more than 30 or 40 mins unless you want to use it on multiple dives. Remember, at 20' the longest you can breath o2 is 45 mins anyway and I think most people would start getting nervous before that.

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Wow...Only 45 minutes? Guess those steel 95's of O2 I got are worthless... :-D