Steel 80 Tank vs steel 100 vs Alum

[D_B]

Just for some more info on tanks .. that chart that Ayisha posted above does not have the new Worthington/XS Scuba steel tanks, and their buoyancy characteristics are different than others ... Scuba Cylinder Specifications from Tech Diving Limited - 928-855-9400

 

[Ayisha]

Thanks D_B! That's very helpful! :blinking:

 

[Venus]

When someone is petite and not very strong, the weight and size of tanks is a consideration - even 5 lbs is noticeable to us. It can make the difference between a frustrating experience before you even get into the water or a smoother, fun experience.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

I agree with everything you have said, I'm small too and have the same problems going from steel at home to an ali on overseas trips

Thanks for the link, but I may need someone clever to translate it for me ..... I feel a bit stupid because I can't work it out

We have different ways of measuring pressure - I dive a 10 litre steel cylinder with a fill of 210 bar if I'm lucky

 

[Ayisha]

We have different ways of measuring pressure - I dive a 10 litre steel cylinder with a fill of 210 bar if I'm lucky

Hi Venus,

OK, so your current tank is a 72 cf steel tank. 210 bar converts to just over 3045 psi. What is the fill capacity of your tank?

Maybe someone knows of a metric table for tank specifications?

Venus, pm me with the brand of tank you have and the fill capacity, and what tank you are looking to convert to.

If you tell me how much weight you are wearing with your current set-up, the table will tell us how much weight you will need, all things being equal (exposure equipment, fresh/salt water) for the tank you want to switch to.

You just need to look at the empty buoyancy of each of the two tanks. Let's say your specific Al tank is 2 lbs positive at the end of the dive; your correct weighting will already include 2 lbs to compensate. Let's say your specific steel tank is -7 lbs at the end of the dive. So the weighting difference in going from Al to steel will be 7 lbs less plus the 2 lbs compensation lbs you no longer need. Therefore, you will wear 9 lbs less with that steel tank than your Al tank. For me, that would mean that while I wear 16 lbs with a specific Al tank, I could wear only 7 lbs with a specific steel tank. It's simpler than it sounds. Remember, though, this simplistic example will work for strictly changing tanks, not also other equipment or salinity or figuring out weighting from scratch.

Most steel tanks start out quite negative (the - numbers on the table) and end up being still slightly negative when empty . Most aluminum tanks start out a little negative, but end up being a little positive when empty, so you have to compensate for this buoyancy characteristic by wearing more weight with aluminum.

Hope that helps! :blinking:

 

[eenglish]

Your advice has giving me some more options to try. To answer one question - the back pain is during the dive. I know it is the HP80 steel tank that is my challenge because it is the only set-up that does that. I don't have the pain with my 80 Alum. Thank you everyone!

 

[Venus]

Maybe someone knows of a metric table for tank specifications?

I also have trouble with fahrenheit and feet :depressed:

 

[drdaddy]

When diving a couple of strenuous dives, I do the first with a steel 100 and the second with a steel 80. The strenuous part is really crawling in and out across the jetty rocks and walls. I'm 5'10, 200 lbs and in reasonably good shape for a man in his mid-fifties.

If you find the steel 80 heavy, don't even think about the steel 100!!!

drdaddy

 

[miss_scuba]

I have a few things for you to consider: If you switch to aluminum tank, you will probably need about 4 pounds extra weight to add, so it will be more to carry.

Steel 100 is way too heavy for a 5'2 girl!

Also, do you carry your weight in your BC pocket? I find that wearing a weight belt better distributes the weight and causes lass pain in my shoulder and back. Not to mention that in an emergency, it is easier to drop.

 

[eenglish]

I don't think my weight configuation is the issue because I'm very comfortable when using my alum tanks. Even with the extra weight. I'm going to check out the new alum tank that's out now. It is HP plus it's neg 2 lbs when empty. Sounds promising

 

[Venus]

Hi Everyone

You may remember me saying that I use a 10 litre steel + a 1.5 litre luxfer pony
My pony was removed from my luggage on my way back from Cocos

I've just bought a 3 litre luxfer and it's so heavy!!

I wear only 1 or 2 kilo additional weight in fresh water

So, here comes the silly question ?.

Will this 3 liter cylinder be more or less buoyant than my 1.5 liter, or would it make so little difference that I don't need to change my weights

I don't want to go to the lake and not be able to get under the water ?
that would make me look silly in front of my peers

though I don't mind being a little heavy first time round and then taking a little weight off for the second dive

Thanks

Venus