# Billionaire Builds Deep Sea Sub



## MA-Caver (Apr 6, 2011)

Now I'm not an engineer or anything but I do have some idea of the pressures that can be found going deep into the ocean. So far only large nuclear subs have managed to penetrate 18,000 feet. He expects this little thing to survive that? Has he even TESTED it? Now imagine the amount of psi at 36,000 feet (Marianas Trench). Uhh yeah okay. 
http://news.yahoo.com/video/science...son-plans-deep-ocean-submarine-dives-24802462


> At sea level, you have one atmosphere of pressure(14.7 psi). Every 33 ft  that you descend adds another atmosphere of pressure. Therefore 3000  ft/33 ft=90.91 atm. Now add the one atmosphere at the surface to get  91.91 atm of pressure at 3000 ft depth. Also, 91.91 atm times 14.7 psi  per atm of pressure equals 1,351 psi.
> 
> Read more: http://wiki.answers.com/Q/What_is_the_ocean_pressure_at_3000_feet_deep#ixzz1ImYGgeBP​



If my math is correct. Then the PSI at 36,000 feet equals to 529,200 = 14.7 psi X 36K 

Has this guy seen the movie "The Abyss" ?


----------



## Empty Hands (Apr 6, 2011)

MA-Caver said:


> Now imagine the amount of psi at 36,000 feet (Marianas Trench). Uhh yeah okay.



This thing made it - with passengers - in _1960_.






If you get a minute, read the story of the two men who went to the deepest part of the ocean, and returned alive to talk about it.  A remarkable feat.


----------



## Sukerkin (Apr 6, 2011)

I sincerely hope that his engineers have done their sums right, I'd hate for Richard to get squished.  

The world needs visionaries like this to lift us up from the mire of simple greed that capitalism otherwise breeds:

http://www.virgingalactic.com/


----------



## MA-Caver (Apr 6, 2011)

Sukerkin said:


> I sincerely hope that his engineers have done their sums right, I'd hate for Richard to get squished.
> 
> The world needs visionaries like this to lift us up from the mire of simple greed that capitalism otherwise breeds:
> 
> http://www.virgingalactic.com/


Yes true... visionaries with the money to do what many of us dream of doing. Yet for us "regular" folk just catching a ride on the actualized dreams would still be out of reach for us. One can imagine the cost of a ride to space much less a trip to the bottom of the sea. 

Another thought is... he's going to need some VERY powerful lights down there to see with and those lights would need to be just as pressure proofed as the sub. I've seen videos of deep sea exploration where there is an absence of sunlight because light simply couldn't travel down that far... but it (for me anyway) was still limited to the cone provided by the lamp. Comparable to trying to light up a big room deep in a cave. Multiple flashes which help illuminate dark corners for a stationary camera are the only (present) way known to produce such imagery. 
How would one do it under such intense pressure?


----------



## Joe1957 (Apr 13, 2011)

Heck, I have been diving for a few years now and must be a wimp, I know I'm not in a metal container but, I go as deep as 40' and presure is enough for me.


----------



## Dirty Dog (Apr 13, 2011)

Empty Hands said:


> This thing made it - with passengers - in _1960_.
> 
> 
> 
> ...


 
These men were *very* lucky to survive. During the descent, they heard a loud bang noise. Couldn't find any problem, and continued down. After their ascent, they discovered that the bang was a crack forming at the entrance tunnel. It was pure luck that the crack did not lead to an implosion. There are good reasons why most deep exploration is done by unmanned subs or robots.


----------



## Dirty Dog (Apr 13, 2011)

MA-Caver said:


> Another thought is... he's going to need some VERY powerful lights down there to see with and those lights would need to be just as pressure proofed as the sub. I've seen videos of deep sea exploration where there is an absence of sunlight because light simply couldn't travel down that far... but it (for me anyway) was still limited to the cone provided by the lamp. Comparable to trying to light up a big room deep in a cave. Multiple flashes which help illuminate dark corners for a stationary camera are the only (present) way known to produce such imagery.
> How would one do it under such intense pressure?


 
Sunlight penetrates to about 600 feet, but obviously that varies depending on the clarity of the water. On 150-200 foot open water dives in clear water (i.e. the carribean) lighting is not an issue (although I always carry a light even on the shallowest dives, to look into the holes and under ledges of the reefs). Obviously it gets gradually darker as you dive deeper. Lighting up the area is actually one of the simpler problems to overcome. Even an inexpensive dive light will be rated to depths of 300-400 feet; much deeper than any recreational diver should go. To go deeper, you can build them stronger. Plus, the lights can be pressurized to counter the external forces. The passengers cannot. The inability to pressurize the passenger compartment is the big limiting factor in the construction of these subs.


----------



## Joe1957 (Apr 14, 2011)

So, when diving in a sub, do you feel the presure when deep diving or does the sub handle all the presure? I know in a plane they presureize the cabin right?


----------



## Dirty Dog (Apr 14, 2011)

Joe1957 said:


> So, when diving in a sub, do you feel the presure when deep diving or does the sub handle all the presure? I know in a plane they presureize the cabin right?


 
Submarines are double hulled, if they are intended for deep operation. Some that are intended for shallow dives (by mechanized standards) may be single hulled. The passenger section is maintained at 1 atmosphere. The space between the two hulls is pressurized to offset the compression of the sea water. If you attempted to pressurize the passenger compartment, then submariners would be limited to the same depths as SCUBA divers. More importantly they would be subject to the same limitations of ascent and descent rates as SCUBA divers. For reference, on a shallow dive (say, 60 feet salt water or less) most certification agencies will allow an ascent at a rate of 60 feet per minute. On deeper dives that is lowered, generally, to 30 feet per minute. 

Then there's the decompression... if your max depth is 190 feet, the No Decompression Limit is 5 minutes. That means that if you're at that depth for less than 5 minutes, you are reasonably safe if you ascend at 30 feet per minute all the way to the top. Anything longer than 5 minutes, and the ascent must be broken up into stages, with stops at various depths to decompress - essentially allowing time for the nitrogen to escape from your tissues.

Yes, there are games you can (and technical divers do) play with the gas mixtures to increase your NDL and accelerate the decompression times. But they're totally impractical in a submarine.

The problems these issues would cause on a submarine are obvious. So passenger compartments are at surface pressure.


----------



## Empty Hands (Apr 14, 2011)

Dirty Dog said:


> The problems these issues would cause on a submarine are obvious. So passenger compartments are at surface pressure.



I've wondered this for a bit - why not pressurize the passenger cabin a moderate amount, say up to 2 atmospheres?  It should effectively halve the outside/inside pressure ratio and increase dive depth by a bit, and it shouldn't have any negative effects on the passengers.


----------



## Dirty Dog (Apr 14, 2011)

Empty Hands said:


> I've wondered this for a bit - why not pressurize the passenger cabin a moderate amount, say up to 2 atmospheres? It should effectively halve the outside/inside pressure ratio and increase dive depth by a bit, and it shouldn't have any negative effects on the passengers.


 
Because your math is in error. Increasing the pressure in the passenger compartment to 2 atmospheres would not halve the pressure gradient. 2 atmospheres is the pressure at a mere 33 feet. At 66, you're at 3. 99, at 4. 132, at 5. At 1000 feet, you're at about 50 atmospheres. 

Modern nuclear submarines are rated to depths of 1500-1600 feet, and have a "crush depth" of something like 2400 feet. 

Changing the pressure in the passenger compartment from 1atm to 2atm would have no appreciable effect on the depth ratings of these subs. And although the NDL for 2 atmospheres is far longer than SCUBA divers are going to stay down, it is certainly not without negative effects when you're talking about an exposure time of weeks.


----------

