Aldora Tanks

[boulderjohn]

Just to add to this confusion....

A dive operator who is giving you LP 85s filled to 3,000 PSI is giving you a little more gas than an operator giving you HP 100s filled to 3300.

 

[kmurray719]

Looks like you've made me go learn (or relearn) something. Thanks.

I tell my students that tank capacity is about how much air can be squished into the tank and that pressure is about how much it had to be squished to get it in the tank. Simplistic, but it seems to help them understand the concept more easily.

 

[Dave Dillehay]

From my observations very few of the Alum 100 tanks are ever filled to the 3300 psi giving those who pay for them about 90cf in a god awful package to carry on your back.


Dave Dillehay
Aldora Divers

 

[uncfnp]

So Dave, to the original question by the op, can you supply her with al 80's if that is her preference?

 

[Prop Joe]

Its called Boyle's law. Google it...
You guys are thinking of a liquid or solid. We breath a gas that is compressible.
Think of it this way if you have a tire and one has 5 psi of air in it and another tire on the same car has 35 psi in it. Which one has more air in it? The one with 35 psi. that si because the one with 35 psi in it has more molecules crammed into it.
Think about it... Our SPG's measure in psi not volume. The more pressure, the more molecules of air to breath. Now when you breath that gas at say 3 atmospheres think about how many little Nitrogen molecules you are exposing your body too. This is the basis of our dive tables and computer algorithms... I find the whole dive physiology concept fascinating.

 

[Gdog]

For some reason, this is a very difficult concept for people to understand. I remember teaching a DM class where all the students were baffled about the differences in tank capacities and pressures.

I don't consider myself a tank guru, but uncfnp is correct. A tank has the amount of gas advertised when it is filled to its rated pressure. If an HP 100's rated pressure is 3500 PSI, it will have 100 cubic feet when it is filled to 3500 PSI. If an AL 100 has a rated pressure of 3300, it will have 100 cubic feet when filled to 3300 PSI.

Where people get confused is when dissimilar tanks are filled to the same pressure. Let's say you have three tanks, all the same advertised capacity (100 cubic feet), and all filled to 3000 PSI. The LP tank (rated at 2640) will have the most, well over 100 cubic feet, because it has been filled over 10% more than its rated capacity. The AL tank (rated at 3300) is filled at about 10% less than its rated capacity, so it has a lot less. The HP tank (rated at 3500) will have the least, because it is filled to about 15% below its capacity.

Very simply and cleanly put. Nice.

 

[Prop Joe]

Yup, HP steel tanks filled by the co-op were not filled to the rated capacity or pressure in the past. I remember getting tanks that were below 3000 psi In years past... Aldora now has their own fill station to make sure that all Aldora tanks are filed to the rated capacity (and the EAN mix is correct with no CO).

 

[Dave Dillehay]

Yes we can supply anyone with Aluminum 80s, but not if that is going to shorten the dive for others. A HP steel 80 is MUCH smaller and lighter than an Aluminum 80 and that would be our first choice.

Dave Dillehay

Aldora Divers

 

[uncfnp]

Double Sue. Don't know your history so just a few thoughts. If you haven't dove with too many men on 120's it does make a difference in BT's. Unless your sac rate is remarkable or the dives are shallow, you might find yourself running your 80 tank quite low, especially for buddy diving. Remember, you are carrying his spare air. Eric and I dive mostly as "solo" but when we are diving together, I usually use a tank about 20 cf smaller. As Dave said, Eric routinely dives 120's to my 100's.

 

[DoubleAA]

When we were with Aldora my wife did dive 100's with me having 120's. There were a few times that we went up early due to this. I couldn't imagine it with 80's.

The 100 steels are as manageable as the AL80s and take weight off your belt. There are tons of smaller framed women that I know diving HP100's regularly.