Why is domed bottom steel tank more popular than flat one?

[lexvil]

Like the Queen song, round bottom tanks make the diving world go ‘round...something like that.

 

[Divin'Papaw]

While not a traditional "scuba tank",,,,most bank bottles are steel and flat bottomed. Some hold 6000psi.
Another reason for round bottoms vs flat bottoms is for weight savings. A round bottom distributes the pressure more evenly than a square flat bottom so less material is needed to achieve the desired strength. That also is why we have curved arches in bridges, similar concept.

I never considered bank bottles since we don't dive them but yes, they are flat on the bottom. Thank you for the reminder! A flat bottomed steel scuba tank would probably be crazy butt-heavy.

Now a round bottomed aluminum tank ... I'm not sure they exist.

 

[2TH DIVR]

Vintage Tanks
Thread on round bottom aluminum tanks

 

[wetb4igetinthewater]

Flat bottomed steal tanks are not uncommon in Europe. I recently learned about them myself. My understanding is that their center of gravity doesn't change as much when being drained compared to round bottomed cylinders available on the market today. Anyone knowing better, please correct me, as my knowledge/experience is thin on this topic.

 

[BRT]

They can? I've never seen a round bottom aluminum tank nor a flat bottom steel tank. I'm not a metallurgical engineer but I'm not sure your statement is correct. I'm open to being corrected but I've sure never seen any examples in my 15+ years of diving.

Steel welding tanks are flat on the bottom.

 

[broncobowsher]

Steel welding tanks are flat on the bottom.

Not really, all mine are concave. Domed but an innie and not an outie. They stand like they are a flat bottom, but if you actually look they are not.

 

[Divin'Papaw]

Flat (concave) bottom steel scuba tanks ... round bottom aluminum scuba tanks ... Learn new stuff all the time on ScubaBoard!

 

[Sam Miller III]

[ATTAC

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[JMBL]

If you watch "Silent World" by J.Y. Cousteau, you'll notice they were diving triple tanks, those were aluminium ones.

 

[broncobowsher]

If you get to see a cut away of tanks the flat aluminum bottom is a lot thicker than the walls. The round bottom steel bottle is about the same thickness all over.