Steel or aluminum tank?

[bamamedic]

Hi!

I'm going to be switching to a BP/W in the near future, and I've been thinking about getting a steel tank, instead of the aluminum one I have...

This may seem like a silly question, but which is better? I use a wetsuit, 'cause I'm just too darn broke to buy a drysuit LOL

I was thinking either an LP85 with an aluminum backplate, or an AL80 with a steel backplate. My issue is I don't want to be overweighted, but I'd really like to cut down on some of the weight I'm wearing on my hips. I thought about pairing an LP85 with a steel backplate because that would virtually eliminate any need to carry weight with a 3mm, but what if I switch to a 1mm suit in the summer? Then I'd be stuck being overweighted...and I wouldn't have any ditchable weight in the 3mm...
I guess it works out to be about the same either way...if I use a steel tank and an aluminum backplate, I'll be able to take off about 4 lbs because I won't have to make up for the buoyancy of the AL80, but if I use a steel backplate and AL80, I can take 4lbs out of the integrated weights because it will be in the backplate instead....

I currently have 14 lbs in a 7mm and hood with my Ladyhawk, and 8 lbs in my 3mm, and I don't feel I'm overweighted.

So, what do you think? Would an LP85 and aluminum backplate be better, or an AL80 paired with a steel backplate?

If it's any help, I'm selecting gear with Cavern/Intro to Cave in mind....

 

[Kingpatzer]

There's a slight flaw in your reasoning.

While steel tanks don't become positively buoyant, they do gain buoyancy as they lose air just as aluminum tanks do. So you have to still figure out what weight you need to carry when the tank is empty.

But, steel tanks are also frequently lighter than AL tanks when full. so you will almost always end up putting on less total dry land weight with a steel tank than with an AL tank.

My question is why not dive steel tanks and a steel plate? You only need enough ditchable weight to make you positive. Most people can get by with that being only a few pounds.

I need 15 pounds to keep me negative in a 3m wet suit in fresh water. If I use a 6# plate and steel tanks that are 9 pounds negative when full, that still gives me a pound to drop and be very slightly positive. As the tank uses gas, it'll go down to only 3# negative. Since most reasons for ditching weight involve lack of air, I'm most likely to need to ditch when the tank is close to empty anyway. That gives me plenty of weight to ditch to become positive.

 

[bamamedic]

Sweet! That makes sense....

 

[Skeeter1097]

That is the way it is Dun. Plate, tank, suit and all you are drooping with. No weights! Get Just nag buoyant. enough that when you let all the air out of your lungs you start to drop. Then add ditch weight to equal the empty weight of the air plus one.
Thats the way I see it anyways.

 

[mike_s]

Hi!


So, what do you think? Would an LP85 and aluminum backplate be better, or an AL80 paired with a steel backplate?

I'd get the steel tank and go with the AL plate given the above choices. that way if you go cave and drysuit then you easily switch the backplate to steel to help with the drysuit. switching plates is easier and switching tanks. That and once most folks have steel tanks, they don't want to switch back to AL.

(not sure if you can even get a tank into the trunk of a Miata though! )

 

[bamamedic]

LOL....you'd be surprised at what I can fit into the trunk of a Miata
I can fit an AL80 in the trunk, and my gear bag, and my overnight bag, and my bag full of snacks into the passenger seat...but it's like a puzzle, everything has to fit in a certain way. It can be a bit of a challenge to fit it all back in...

I have no idea what I'm going to do when I've got to fit a scooter and doubles into that car...

...and that's the reason I'm trying to convince my significant other to take Cavern and Intro to Cave with me...He's got a Jeep

 

[bamamedic]

mike_s:

What do you think about a steel backplate with a steel tank? Do you think I'd be overweighted?

 

[mike_s]

mike_s:

What do you think about a steel backplate with a steel tank? Do you think I'd be overweighted?

With a thin wetsuit.... most likely. But some people do it.
with a THICK wetsuit...... you'll prob be ok.

with a drysuit..... you'll be ok...



Here's some stuff to consider:

When you dive any tank or BC/plate configuration, you have to put on X amount of weight to make yourself neutral buoyant.

A steel tank might be lets say 6 pounds on average more negative buoyant than an AL80, so that's 6 pounds you can take off the led weights on your waist. (BC if integrated).

A steel backplate would be traded off similar. So lets say the backplate weighs 6 pounds.... so that's 6 pounds you take off your weight belt.


So in this combination, the example I used above you'd take 12 pounds off your weight belt. Since you're wearing 14 pounds with a 7mm (with AL80), you'd only have to wear on average 2 pounds of weight with the tank and plate in my example.

If you switched to your 3mm wetsuit, you said you had to wear 8 pounds. So in this instance you'd be 4 pounds overweight/negative. This isn't a great amount to be heavy, but doesn't provide the best 'peak buoyancy'. However you'd prob be ok.... but not reccomended.... (but there will definately be someone here who disagrees with that.)

In this situation, an Aluminum backplate would be much better. The ALuminum Dive Rite backplate is about a pound and a half for example. (dry weight).


Now... disclaimer time... not all backplates and tanks have the same weights or buoyancy characteristics. So it's different for each configuration. Just like it'd be different for 3mm verses 7mm. Fresh verses saltwater will make a difference also.

so... hope that helps some.

mike

 

[bamamedic]

Thanks! That does indeed help

 

[Colliam7]

I'm going to be switching to a BP/W in the near future, and I've been thinking about getting a steel tank, instead of the aluminum one I have... ... I currently have 14 lbs in a 7mm and hood with my Ladyhawk, and 8 lbs in my 3mm, and I don't feel I'm overweighted. So, what do you think? Would an LP85 and aluminum backplate be better, or an AL80 paired with a steel backplate?

Start with a SS BP. Whether you pair that with an AL80, or even a LP steel, is not as big an issue. You can figure out which tank works best with the SS plate and the particular exposure suits you use in specific environments. One nice thing is that AL 80s are ubiquitously available. If you are diving with more neoprene, you will definitely want the SS. Even with a 3mm the SS is nice with an AL80. You mention the possibility of cavern and cave, so the LP85 reference is understandable. If you get the bug, end up going full cave with doubles, etc., you might find a need for an AL BP as well. But, you are talking an additional $65, and some webbing and D-rings added on, so getting an AL plate in the future is not a big deal. (Or, at least it will be a lot less than the double tank set-up, drysuit, deco bottles, additional regulators, etc. )