Asahi tank volume.

[cub175cw]

I picked up three asahi tanks for a great price and I’m trying to figure out their volume. Anyone have a reference?

Stamp says asahi M7901 ITS. They’re 3500 psi steel. Doesn’t say Genesis anywhere but the local hydro place had a hell of a time getting them to seal on their machine. They’re DOT and the only other number besides the s/n is TP5250.

Help, please. I’m looking for volume and buoyancy performance at 500psig.

 

[runsongas]

do you have a picture of the tank markings? how tall are they without the valve?

generally, they should have a stamp with the capacity and the buoyancy is a bit more negative than worthington/faber/pst but not as bad as heiser. roughly -6 to -8 when empty iirc.

 

[cub175cw]

Pictures attached

 

[cub175cw]

Another

 

[cub175cw]

They are 30 inches, deck to stem.

 

[2airishuman]

I don't think the markings will tell you. If you compare the diameter and length to other HP steels, you'll get your answer. The sizes are pretty much the same within 1" length or so for Faber, Worthington, PST, and Asahi. As the Asahi cylinders are spun they have thicker bottoms and weigh more (and more negatively buoyant), but are otherwise comparable.

 

[RyanT]

They are probably 120s, or thereabouts. I have a set of Ashai (3442) that are 26 inches tall and they 100 cf tanks. These tanks are HEAVY in the water. My 100s are about -5 lbs empty. The 120's might be slightly more buoyant than the 100s, but I would still count on them being very negative. I originally had mine doubled up, but I split them because they were just too heavy to dive as a set of doubles. They are fantastic as single tanks though.

 

[runsongas]

are there any more markings to the right? there should be a stamp sayiing st100 or st120 etc which means steel 100cf or steel 120cf

they probably hp120 unless if they are not 7.25 inch diameter

 

[uncfnp]

They are probably 120s, or thereabouts. I have a set of Ashai (3442) that are 26 inches tall and they 100 cf tanks. These tanks are HEAVY in the water. My 100s are about -5 lbs empty. The 120's might be slightly more buoyant than the 100s, but I would still count on them being very negative. I originally had mine doubled up, but I split them because they were just too heavy to dive as a set of doubles. They are fantastic as single tanks though.

are there any more markings to the right? there should be a stamp sayiing st100 or st120 etc which means steel 100cf or steel 120cf

Agreed. It will be the numbers after the ST in the picture. Most likely 120’s. My 80’s are about 22 inches.

I love my 80’s but 120’s are going to be very heavy.

 

[EdC]

I have similar tanks Asahi 3500 spun but mine are only 26 from floor to the tank/valve face. They also have a stamp that says Japan ST100, they are 12/99 vintage.

I used my set and a rental last summer in a three tank day trip and I found these to be about 2# more negative than the shops 100hp tank (don't remember the brand).