mythbusters

[Burntchef]

the good video starts at the 3 minute mark, they try to see if the myth of a deep sea diver at 300 foot depth will have his body sucked up into the helmet if the gas supply line is cut.


http://www.youtube.com/watch?v=xpo18cjoYcg

[spatman]

holy crap. what a way to go.

[selkie]

Always check the non-return fitting!!!!! How about the guy sitting on the toilet in the Saturation Chamber pressurised to 600' when the tender opened the valve to flush the waste system. Same effect different end.

[ktb]

1) That was gross.

2) I have renewed respect for commercial divers. (Defied--I'm glad you're no longer doing that!)

3) It may have been gross to see, but seriously . . . how can I get a job on that show?!?

[Joshua Smith]

the good video starts at the 3 minute mark, they try to see if the myth of a deep sea diver at 300 foot depth will have his body sucked up into the helmet if the gas supply line is cut.


http://www.youtube.com/watch?v=xpo18cjoYcg

Help me out with the physics, here: I've been to 300' (OK, 295', to be precise), and my head didn't implode. Why did the surface supplied diver's head implode, exactly? What's the difference?

[Joshua Smith]

the good video starts at the 3 minute mark, they try to see if the myth of a deep sea diver at 300 foot depth will have his body sucked up into the helmet if the gas supply line is cut.


http://www.youtube.com/watch?v=xpo18cjoYcg

Help me out with the physics, here: I've been to 300' (OK, 295', to be precise), and my head didn't implode. Why did the surface supplied diver's head implode, exactly? What's the difference?

Wait- OK, is it because he has a hose that vents directly to the surface, and the pressure differential causes, uh.....problems?

[Mattleycrue76]

the good video starts at the 3 minute mark, they try to see if the myth of a deep sea diver at 300 foot depth will have his body sucked up into the helmet if the gas supply line is cut.


http://www.youtube.com/watch?v=xpo18cjoYcg

Help me out with the physics, here: I've been to 300' (OK, 295', to be precise), and my head didn't implode. Why did the surface supplied diver's head implode, exactly? What's the difference?

Wait- OK, is it because he has a hose that vents directly to the surface, and the pressure differential causes, uh.....problems?

The answer to that one is yes. I had to think about it for a minute too.

[Joshua Smith]

Then......why would a surface supplied diver even have a line that vents to the surface? Couldn't they exhaust gas into the water, like any open circuit diver?

[Burntchef]

Then......why would a surface supplied diver even have a line that vents to the surface? Couldn't they exhaust gas into the water, like any open circuit diver?

so they can get gas in, are you huffing silver spray paint again dude?

[Aquanautchuck]

They have had some very real tests in the past but that one was just to gross. Especially when at the beginning when it first came out of the Human analogs mouth. Loved it.

[Joshua Smith]

Then......why would a surface supplied diver even have a line that vents to the surface? Couldn't they exhaust gas into the water, like any open circuit diver?

so they can get gas in, are you huffing silver spray paint again dude?

Ran outta teh slliver. Hittin' the glod.

No, really- why can't they just have a line that supplies gas at ambient pressure, and an exhaust valve?

[defied]

Then......why would a surface supplied diver even have a line that vents to the surface? Couldn't they exhaust gas into the water, like any open circuit diver?

This "Myth" was based off of the early days of hard hat diving, when the old copper helmets didn't have one way valves. and a large percentage of compressor pumps were manually cranked using elbow grease.
These helmets do have one way valves now (at least 1), and this has no longer become an issue.

The Sat - sh1tt3r story always cracked me up, and wouldn't surprise me if it were true at the same time.

1) That was gross.

2) I have renewed respect for commercial divers. (Defied--I'm glad you're no longer doing that!)

3) It may have been gross to see, but seriously . . . how can I get a job on that show?!?

Meh. Thanks, but it was a fun job. Paycheck sucked.

D(B)

[sheahanmcculla]

Meh. Thanks, but it was a fun job. Paycheck sucked.

D(B)

Ha, that's not what the DIT recruiter tells you!

[Marc]

Then......why would a surface supplied diver even have a line that vents to the surface? Couldn't they exhaust gas into the water, like any open circuit diver?

This "Myth" was based off of the early days of hard hat diving, when the old copper helmets didn't have one way valves. and a large percentage of compressor pumps were manually cranked using elbow grease.
These helmets do have one way valves now (at least 1), and this has no longer become an issue.

The Sat - sh1tt3r story always cracked me up, and wouldn't surprise me if it were true at the same time.

1) That was gross.

2) I have renewed respect for commercial divers. (Defied--I'm glad you're no longer doing that!)

3) It may have been gross to see, but seriously . . . how can I get a job on that show?!?

Meh. Thanks, but it was a fun job. Paycheck sucked.

D(B)

I now understand (obviously with the video aid) why the Navy Chiefs were beating up on the line tenders so bad..... a hungover 20 year old with the ability to turn a guy into helmet soup is a scary thought.

I am a bit surprised that it wrinkled that helmet, though.

[defied]

Ha, that's not what the DIT recruiter tells you!

Don't get me started with DIT's "Extreme" advertising.

I am a bit surprised that it wrinkled that helmet, though.

I'm not. There was a ton of corrosion on that hat. I would like to know if a better conditioned hat would do that.

D(B)

[blt2go]

Then......why would a surface supplied diver even have a line that vents to the surface? Couldn't they exhaust gas into the water, like any open circuit diver?

No, really- why can't they just have a line that supplies gas at ambient pressure, and an exhaust valve?

The Mythbuster routine was simulating an air supply hose failure combined with a failed non-return valve. The air supply line is what supplies the air at something close to ambient.

Similar to the story about the toilet in the sat chamber story, there are stories about the toilets on some cruise ships that use vacuum to assist in the flushing. I have heard stories of large people (whose rears evidently can make a good seal) who have courtesy flushed and either stuck themselves to the toilet or actually caused themselves major damage by having their intestines sucked out a bit. Yeouch! That would leave a mark...

[defied]

Similar to the story about the toilet in the sat chamber story, there are stories about the toilets on some cruise ships that use vacuum to assist in the flushing. I have heard stories of large people (whose rears evidently can make a good seal) who have courtesy flushed and either stuck themselves to the toilet or actually caused themselves major damage by having their intestines sucked out a bit. Yeouch! That would leave a mark...

I wonder if people would appreciate if they were constipated, or "Stopped up"?


D(B)

[Sounder]

Wow. Nice find Howard.

[Sounder]

Is it because the system is still sealed? I'm thinking that if we were to lose pressure like that at 300fsw in a drysuit, it would involve a total suit flood, which would then equalize pressure to prevent implosion. With no hard-hat, our heads are already equalized so there's no place for or guts to go.

Somehow, I still can't get the mental image of my kidney flying into my mask through my eye-socket out of my mind though.

[Aquanautchuck]

Somehow, I still can't get the mental image of my kidney flying into my mask through my eye-socket out of my mind though.

That kind of gets to me to.

[lizard0924]

My teenage son watches Mythbusters religiously, and we all watched this episode recently. As disgusting as it was, it was also the first time that my son has expressed even a remote interest in anything dive related. I'm keeping my fingers crossed that his interest grows. Go, Mythbusters!

[defied]

Is it because the system is still sealed? I'm thinking that if we were to lose pressure like that at 300fsw in a drysuit, it would involve a total suit flood, which would then equalize pressure to prevent implosion. With no hard-hat, our heads are already equalized so there's no place for or guts to go.

Somehow, I still can't get the mental image of my kidney flying into my mask through my eye-socket out of my mind though.

On a surface supply line with no check valve, or a broken one, you have a path for the lighter gas (air) to be pushed out of the water. With the suit they were using, it is a completely closed system. A diver gets in to the suit, at which point a chest plate is attached to the suit, and the bolted on top of that. If the amount of air pressure sent down the line is not enough to equalize the pressure of the water pushing against the diver, it's going to become very uncomfortable.

I know you know this, but I'm just giving people in general a better idea of what is happening here. This is a great opportunity to explain pressure effects on the body. 0] All the people who know more than me, please jump in (That's a lot of people)!

The pressure of the water is forcing the air in the suit and the air line up to where it is no longer lighter (1ata) then the gas, or liquid around it. The Diver unfortunately gets in the way of that process.

Want a great example? Why is a snorkel only so long? Build a 4 foot snorkel, and try to breathe through it while you are at 3.5fsw. It's not so easy due to the pressure surrounding your lungs. Imagine that divers suit is a lung sack, but at 300 feet.

D(B)

[Joshua Smith]

The Mythbuster routine was simulating an air supply hose failure combined with a failed non-return valve. The air supply line is what supplies the air at something close to ambient.

OK, *NOW* I get it- I missed that part of the explanation, somehow. Thanks!

[ketralis]

Oh dear god... Wow... Just Wow... and maybe some Ick... Yeah, gotta throw in some ick. lol. That was actually pretty cool.
-Kevin