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ThePipingSheriff

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Messages
21
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Location
Tennessee
# of dives
500 - 999
Recently I have been looking at tanks. Alum vs. Steel. I saw in a catalog that a weighted tank boot can be mounted on an Alum tank to bring it's weight up to or close to a steel tank.
If this sort of weighted tank boot was placed on the tank wouldn't it have a tendancy to keep the diver in a vertical position? If so , how would this be overcome? It would seem to me that a lot of energy might be spent on staying horizontal?
Is there some sort of weighted sleeve that goes over Alum tanks? It seems like something like that would help evenly distribute the weight and aid in staying horizontal?

Thanks!
 
They do make Neutral 80's in aluminum, I have one.

I'm not promoting gear for the following link, its just the first hit when I searched for the tank
N80

If your BC has trim pockets, use them

Back inflate BC also helps
 
TPS,
You're right, the add-on tank weight will have a tendency to put the diver in a heads up position. This can be offset to some extent by moving the tank strap further down on the tank.

There are also available weight pockets that can be attached to the tank strap in order to add some weight, but keep it more centrally located with respect to the center of gravity.

There are those divers with BC's or BP/wings that have two tank straps who'll put a weight pouch on both the upper and lower tank straps, but on opposite sides in order to fine tune their trim even more finely.
 
ThePipingSheriff:
Recently I have been looking at tanks. Alum vs. Steel.... Thanks!
If you haven't bought the tank yet, why not just get the steel?

BTW, leave your pipes on the beach. It'll play the devil with your trim! :wink:
 
Rick Inman:
If you haven't bought the tank yet, why not just get the steel?

BTW, leave your pipes on the beach. It'll play the devil with your trim! :wink:


Rick,
I have not purchased the tank yet and I'd have to say that I am leaning towards Steel. Since I lack experience I know that my ability to ascend at a proper rate will take time to perfect. If I'm going up too fast I know that if I dump air from my bc I have the weight of the Steel tank to hold me back. Or at least that's the way I feel?
Isn't the idea to dive with as little added weight as possible?

BTW, the pipes don't get near the water.

Thanks!
 
Ed,

As you know at the end of a dive an Aluminum tank is going to be four pounds positive. This has to be accounted for. A very simple method that is virtually cost free is to either weave a four pound weight through your tank strap or get a weight pouch (XS suba tank weight pouch) is about $8 from Leisure Pro which my wife uses. Because this weight is higher up the tank it doesn't force your butt and legs down and it make staying horizontal much easier.

I dive 95 and 120 low pressure tanks in Cozumel and 100 and 120 high pressure tanks back home. I do have two 80 aluminum's that I now use for stage and deco bottles.

Steel tanks are lighter at the end of the dive because you have of course used up the air but they are still negative and you won't find your butt floating with a steel.

Before you buy a steel tank do a search to find out whether high pressure or low pressure is best for you. If you're local dive shops can't fill to 3500 or better then you're best going with a low pressure (2400 to 2600) that they can easily fill.

If you decide on high pressure you will have to convert all your regs to DIN and then buy a DIN adapter that will allow you to use them on standard yoke valves if you go on vacation.

If you want to see the difference of what a steel tank holds look at the massive size of an 8 inch diameter 100 cu ft. aluminun and compare it to a 95 low pressure or 100 HP which will both hold more air.

Pressed Steel, OMS and Faber are all good brands. You can find new and used models on Ebay. Ebay has new Faber's for $235 to $285 which includes shipping.

I'm 6' and can dive with a 120 but perfer the 95's or 100's.

Jim
Louisiana
 
Jim Baldwin:
Ed,
Before you buy a steel tank do a search to find out whether high pressure or low pressure is best for you. If you're local dive shops can't fill to 3500 or better then you're best going with a low pressure (2400 to 2600) that they can easily fill.

If you decide on high pressure you will have to convert all your regs to DIN and then buy a DIN adapter that will allow you to use them on standard yoke valves if you go on vacation.

Jim
Louisiana


Great thread, I'm in the middle of the same evaluation.

My questions - Is the 3500 fill capability a big issue? I would assume any fill station would have this capability. How many fill stations can do this, eg, 25% or 50% etc.?

I have seen DIN adapters which seems to be a good way to save my reg/first stage for use on vacations.

Also, I am checking out pony bottles for redundancy, these seem to be only available in aluminum in the 13-30 cf range. Are there steel options?
 
Jim Baldwin:
Before you buy a steel tank do a search to find out whether high pressure or low pressure is best for you. If you're local dive shops can't fill to 3500 or better then you're best going with a low pressure (2400 to 2600) that they can easily fill.

If you decide on high pressure you will have to convert all your regs to DIN and then buy a DIN adapter that will allow you to use them on standard yoke valves if you go on vacation.
Jim, if I get a high pressure E7-100 it says the working pressure is 3442, but the E7-100's I was looking at from DiveRiteExpress have these cool looking 200 BAR Pro DIN/K valve, which works out to 2900 psi if my math doesn't fail me.

My current LDS fills AL80's to 3000 psi all the time, which that same 3000 psi would translate to 89 cf in the E7-100's, but if I get one or two of these do I need to limit the fill to 2900 psi due to that Pro DIN/K valve? If thats the case, why wouldn't I want to stick to renting AL80's? Or change out that convertible valve with a stock K valve? :06: Wouldn't an "overfill" (not really an overfill on that tank, but you know what I mean) to 3300 psi for 98 cf (+/-) be dangerous with that valve?

I'd only go to all this trouble and expense because I'm all about additional bottom time :) and I like the fact that they are two inches shorter than an AL80 plus they are more negatively bouyant.

FWIW, the K valve yoke on my Titan LX first stage is rated to 232 BAR, like you'd expect, which is what I'd be using with the tank for the foreseeable future. These would be for EAN36 and EAN32 exclusively.

Thanks in advance for any additional enlightment!
 
stsomewhere:
Jim, if I get a high pressure E7-100 it says the working pressure is 3442, but the E7-100's I was looking at from DiveRiteExpress have these cool looking 200 BAR Pro DIN/K valve, which works out to 2900 psi if my math doesn't fail me.
I think that when people say a "200 bar" valve vs a "300 bar" valve, they mean the "232 bar" valve.
 
jonnythan:
I think that when people say a "200 bar" valve vs a "300 bar" valve, they mean the "232 bar" valve.

Not really. There are 200 bar valves and there are 232 bar valves and then there are 300 bar valves.

Operating pressure is stamped on the back of the valve pillar.
 
https://www.shearwater.com/products/peregrine/

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