Tank weight

[GregFil]

Here is my question:
Usually I am using a bit more air than my partner. So I decoded to get myself steel LP 100.
I did a few dives with 100 and I like it. After few weeks of searching I found used scuba tank which is 100 steel. I get it for try out. After I fill it out with air it feels like it really heavy. So I put it on scale. It weights 72 lb. I did search on internet and it shows that tank should weight around 40 lb + 6lb for air.
Can somebody explain to me how it supposes to be?
The deal is I am using a lot of air and I do shore dives, so capacity and weigh is important.
Please advice.
Thank you

 

[Charlie99]

WHICH steel 100 is it?

There are lots of different manufacturers and various models of steel tanks.

http://www.huronscuba.com/equipment/scubaCylinderSpecification.html lists a lot of tanks, but I dont' seen any 100 cu foot tanks that are anywhere near 72 pounds.

Are you sure it isn't full of water?? 30 pounds of water would get the typical 100cu ft tank up close to the 72 pounds you measured. The internal volume is roughly 1/2 cu foot, so if full of water it would be about 30 pounds heavier than normal.

What are the markings on the tank?

 

[GregFil]

Thank you for response... I found the answer:

http://www.scubaboard.com/forums/tanks-valves-bands/193295-beuchat-heiser-tanks.html

It’s Beuchat tank.... made in 90's
That's why it so heavy

I appreciate your quick response

 

[Web Monkey]

Here is my question:
Usually I am using a bit more air than my partner. So I decoded to get myself steel LP 100.
I did a few dives with 100 and I like it. After few weeks of searching I found used scuba tank which is 100 steel. I get it for try out. After I fill it out with air it feels like it really heavy. So I put it on scale. It weights 72 lb. I did search on internet and it shows that tank should weight around 40 lb + 6lb for air.
Can somebody explain to me how it supposes to be?
The deal is I am using a lot of air and I do shore dives, so capacity and weigh is important.
Please advice.
Thank you

Some steel tanks (as you just found out) are massively negative.

It's not just a question of the tank being heavy, but it's possible that it would make you negative enough that ditching your weights in an emergency would have no effect.

For example, with the above tank, if your BC failed, you would have no way to get to or remain on the surface.

Terry

 

[Gombessa]

A Heiser 104 is 47lb empty, with valve. Assuming an overfill weighing 10lb, that's only 57lb, a far cry from 72.

A Heiser 120 is 55lb empty, which gets you to 65lb full. Is Another 7lb within the margin of error? Maybe....

As you found, a Heiser 140 is 63lb empty, which puts you right in the 72lb ballpark when filled. Either way, it's not likely that you have a 100cf tank.

In cold water diving, a single Heiser 104 would probably be managable. You'd drop maybe 8lb from a ~24-26lb weight belt. The larger Heisers would seem to be problematic.