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Asahi tank volume.

Discussion in 'Tanks, Valves and Bands' started by cub175cw, Jan 27, 2018.

  1. cub175cw

    cub175cw Public Safety Diver

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    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.
     
  2. runsongas

    runsongas Great White

    # of Dives: 500 - 999
    Location: California - Bay Area
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    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.
     
  3. cub175cw

    cub175cw Public Safety Diver

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    Pictures attached
     

    Attached Files:

  4. cub175cw

    cub175cw Public Safety Diver

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    Another
     

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  5. cub175cw

    cub175cw Public Safety Diver

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    They are 30 inches, deck to stem.
     
  6. 2airishuman

    2airishuman ScubaBoard Supporter ScubaBoard Supporter

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    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.
     
    rjack321 likes this.
  7. RyanT

    RyanT ScubaBoard Supporter ScubaBoard Supporter

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    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.
     
    rjack321 likes this.
  8. runsongas

    runsongas Great White

    # of Dives: 500 - 999
    Location: California - Bay Area
    4,172
    1,867
    113
    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
     
  9. uncfnp

    uncfnp ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
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    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.
     
    Last edited: Jan 27, 2018
  10. EdC

    EdC Photographer

    # of Dives: 100 - 199
    Location: Connecticut
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    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).
     

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