Will this make my tank explode?

[Sat Diver]

Fortunately, I wasn’t in the barrel on those dives. Both times the bailouts were hanging in the bell but the hatches were open because the whole system was decompressing, the vessels were going off contract, and already tied to the pier. I am sure it was worse inside, but it was pretty terrifying on the console too. Lots of dirty laundry on those days! :blush:

One was a top-mate and the bell filled with 1½% deep mix from the bailout. Everyone would overfill the bailouts anyway for the extra time to come home. It was a good thing that we had a bell Oxygen monitor that could be read from the mating trunk because the PPO2 dropped from 0.3 to below 0.1. Like you, bailouts were never in the deck chambers unless being passed through the medical/utility lock for maintenance.

the dive supervisor must have needed a nappy change when he saw the partial pressure drop like that:shocked2:

 

[Akimbo]

the dive supervisor must have needed a nappy change when he saw the partial pressure drop like that:shocked2:

The PPO2 hardly changed in the chambers, only the bell. Besides, everyone was pretty well spent from tracking down the noise from the blow-out disk so low PPO2 in the bell was minor.

If this is a little too “inside baseball” for most reading this, a top-mating bell sits on top of a transfer chamber like an up-side-down glass. The hatch is around 24" in diameter and the bell is 5-6' in diameter. When the bailout disk blew, the low Oxygen deep mix displaced some of the bell’s atmosphere into the lower chamber. But the chamber complex volume is huge compared to the bell so the change in PPO2 was barely measurable (with standard instruments). The chamber complex depth barely increased, but the bell PPO2 would drop a lot.

It is not uncommon for the bell PPO2 to be on the low side anyway when decompressing the whole system. Some supervisors are pretty good at making the divers go up to manually add Oxygen during decompression so the bell can be used for emergencies, others not so much. It is more common for the bell to stay pressurized for months at a time on some of these systems while crews change out through a series of deck chambers so bringing the whole system up at once was unusual.

The whole issue with low O2 percentage in the bell is if a person goes up, they will immediately lose consciousness and (hopefully) drop back down the ladder. The body reacts to virtual hypoxia (like 1% Oxygen) with almost instant unconsciousness. It also happens when people are testing BIBs (Built-In-Breathing or emergency masks) or hats on an umbilical that have not been completely purged of deep mix. Hope this makes sense to everyone.

 

[knotical]

... no silly AL tanks aswell.
btw only the usa and surroundings use them, the rest of the planet use steel.

Interesting. I coulda sworn I saw aluminum scuba cylinders in Australia and South Africa.

 

[Saudi-Diver]

I dive in Scotland and Yes we do have burst Disks in our Valves and shock horror some people even use aluminum alloy tanks.

 

[divinginn]

I want to see a tank explode. sorry I couldn't resist.

 

[Garrobo]

Of course it will explode. NOT.

 

[jimthediver]

This thread reminds me of the ancient arguement, spawned by the movie "Jaws" when it first came out (yes I am really that old). Would a tank really explode, thereby dispatching Bruce the shark, if you shot it with a gun? We would debate this during surface intervals. The crew had very diverse backrounds so we always had lots of 'expert" opinions.

 

[txapacheguy]

No burst discs (thank you) but no silly AL tanks aswell.
btw only the usa and surroundings use them, the rest of the planet use steel.

Not to jump on the bandwagon, but all the tanks I recall using in South Korea were Aluminum 80's...

 

[Kilili]

btw only the usa and surroundings use them, the rest of the planet use steel.

This is true only if you consider the "usa and surrounding area" to encompass about 85% of the planet.

I like steel, but let's stay grounded in reality.