Armed Polite Society
Main Forums => The Roundtable => Topic started by: K Frame on February 12, 2019, 01:34:52 PM
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Neat piece about the discovery of the final resting place of the USS Hornet, CV-8.
https://www.cbsnews.com/news/uss-hornet-wreckage-world-war-two-warship-discovered/?fbclid=IwAR0JvoWgoYw5lVSkqGvJyB9JMy3nsUwljRPlj-C0_Fc1m8ZnHe_s5Aibdw0
Many years ago, some years before Robert Ballard found the Titanic, my Dad and I were talking and I mentioned that it would be neat if they dive and find these ships and see what condition they're in. He opined that they were too deep to find.
Little did either of us know of the technology just over the horizon...
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https://www.foxnews.com/science/wreck-of-wwii-aircraft-carrier-uss-hornet-discovered-in-the-south-pacific
The ship looks to be in surprisingly good shape after such a long submergence. Not just a pile of rust at all.
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Some of those photographs look unreal. The cloth covers on the hoses of the one gun and the tractor. It's amazing how well preserved it is.
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https://www.foxnews.com/science/wreck-of-wwii-aircraft-carrier-uss-hornet-discovered-in-the-south-pacific
The ship looks to be in surprisingly good shape after such a long submergence. Not just a pile of rust at all.
Depth is 17,500 feet. My fuzzy recollection is that there's not much oxygen in the water at that depth, and it's cold, so rusting doesn't progress very rapidly -- if at all.
The wreck was found at a depth of nearly 17,500 feet.
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(Salute)
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Depth is 17,500 feet. My fuzzy recollection is that there's not much oxygen in the water at that depth, and it's cold, so rusting doesn't progress very rapidly -- if at all.
I was amazed at the condition of the Hornet vs. the Titanic, which was found at 12,500 feet. I wonder if the differences are due to depth, the difference in construction between a passenger liner vs. a warship, or different steel metallurgy.
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I was amazed at the condition of the Hornet vs. the Titanic, which was found at 12,500 feet. I wonder if the differences are due to depth, the difference in construction between a passenger liner vs. a warship, or different steel metallurgy.
Well, and you also have to consider the affect of being split in two when you talk about the Titanic.
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Same reasons Yorktown is in such great shape, depth, and the fact that both were fairly evenly flooded going down, both having been torpedoed multiple times (fewer large air pockets trapped in compartments to be crushed). And add the fact that neither apparently suffered a magazine explosion unlike many other warships.
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And BTW: Hiei has been found as well https://news.usni.org/2019/02/06/40942?utm_source=USNI+News&utm_campaign=6920b178de-USNI_NEWS_DAILY&utm_medium=email&utm_term=0_0dd4a1450b-6920b178de-230407241&mc_cid=6920b178de&mc_eid=f2dffbb563
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Cool, thanks for the link.
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Looked it up out of curiosity:
Pressure at 17,500 foot depth of sea water.
7791.10 PSI
530 ATM (BAR)
Wow.
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That is a lot. At that kind of pressure, canned goods, most sealed containers, even some hydraulic systems would be crushed.
Odd ball APS question: would an ordinary cartridge, say a 30-06, be crushed or would the water push past the neck?
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Crushed like an empty beer can.
Brass is soft and there is often empty space inside the case.
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That is a lot. At that kind of pressure, canned goods, most sealed containers, even some hydraulic systems would be crushed.
Odd ball APS question: would an ordinary cartridge, say a 30-06, be crushed or would the water push past the neck?
I suspect whether the water seeps in depends on how fast the pressure is built up, that is how fast the ship goes down.
But neglecting that, in general, thinner walls of a vessel are required to contain pressure than to resist outside pressure.
If there's inside pressure, the walls are subject to tensile stress which gets distributed. But if there's any fault in the wall of a vessel resisting outside pressure, the stresses are concentrated at the fault and catastrophic failure occurs. (That's why vacuum packed canned products have ribbed walls --to strengthen them.)
I suspect as pressure builds up on a cartridge, ultimately the bullet would be forced into the case before the walls collapse.
I always used an inertia bullet puller, so I don't know what force is required to pull a bullet* (without the case neck expanding from burning powder pressure), but if someone knows the force to pull a bullet, it would be the same force (approximately) to force the bullet back into the case.
The fluid pressure required to estimate** this is easily calculable, since force equals pressure times area, and we know the frontal area of the bullet. E.g. a .308 bullet has a frontal area of 0.0745 square inches if my arithmetic is correct. ETA at that depth, that would be 580 pounds of force pushing the bullet back in the case. Assuming the case didn't collapse before it got that deep.
Terry, 230RN
*Or to seat a bullet, offhand.
** "Estimated," that is, neglecting other variables, such as the clamping force on the neck due to the outside pressure.
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Remember, though, that military ammunition as would be found on the Hornet had asphaltum applied around the case neck to waterproof it, and another type of sealer around the primer.
Don't know how well it would resist those kinds of pressures, but I know pulling a military bullet is a HUGE pain in the ass.
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Oh, I'm aware of that as well as crimping. You will note my efforts to talk about this in general terms. A starting point, as it were. My posts sometimes get too detailed if I start throwing every variable around.
It's about at this point one starts thinking about empirical testing.
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It's about at this point one starts thinking about empirical testing.
Great idea. YOU take some ammo down to 17,500 feet, see if it squashes or if the bullets get pushed in. If you make it back to the surface and you haven't turned into a pancake -- give us a report.
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Things can go rodeo real fast with leaks in to the people tank at depths where the pressure is extreme.
https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593) (https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593))
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Great idea. YOU take some ammo down to 17,500 feet, see if it squashes or if the bullets get pushed in. If you make it back to the surface and you haven't turned into a pancake -- give us a report.
Aw, gee, Hawkmoon.
No need to. We can develop those pressures and more at sea level.
Not, you understand (I hope) that I am seriously suggesting empirical testing in this case, but it is about at this point in a technical investigation that we assess the need and costs of an actual test regime.
As an example, all ballistic calculations and tables were initially based on empirical testing. Including the value of gee.
=D
Terry, 230RN
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(https://i.imgur.com/2rYtOBq.jpg)
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(https://i.imgur.com/709klag.jpg)
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(https://i.imgur.com/5dvfini.jpg)
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(https://i.imgur.com/CIeICLK.jpg)
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No need to. We can develop those pressures and more at sea level.
What fun is that? >:D
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Things can go rodeo real fast with leaks in to the people tank at depths where the pressure is extreme.
https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593) (https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593))
Poking around on the Thresher, I found this interesting tidbit. I didn't know they did this:
Following Navy tradition, this class of subs was originally named Thresher after the lead boat. When Thresher was struck from the Naval Vessel Register on 16 April 1963, the class name was changed to that of the second boat, Permit, and Thresher is now officially referred to as a Permit-class submarine. Having been "lost at sea," Thresher was not decommissioned by the U.S. Navy and remains on "Eternal Patrol."
Same link as RoadKingLarry's.
According to the analysis of the Scorpion's sinking, the catastrophic collapse due to pressure occurred in 0.1 second.
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On a related note the USS Wasp has been found as well
https://www.history.com/news/wwii-shipwreck-uss-wasp-discovery
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The Lexington was also recently found.
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The Lexington was also recently found.
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That was a while back. And Yorktown as well.
Waiting on Akagi, Kaga, Soryu, and Hiryu to be found.
Some years ago some wreckage from Kaga was reportedly found but not the ship itself
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Remember, though, that military ammunition as would be found on the Hornet had asphaltum applied around the case neck to waterproof it, and another type of sealer around the primer.
Don't know how well it would resist those kinds of pressures, but I know pulling a military bullet is a HUGE pain in the ass.
Pro tip: Running a military cartridge through your seating die first and pushing the bullet in just a little breaks the asphaltum seal and facilitates pulling it. (I've never encountered a slug cemented in place firmly enough to collapse the shoulder when doing this. Haven't tried it with bullets staked in place.)
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That was a while back. And Yorktown as well.
Waiting on Akagi, Kaga, Soryu, and Hiryu to be found.
Some years ago some wreckage from Kaga was reportedly found but not the ship itself
Lexington was found last year. https://www.paulallen.com/uss-lexington-wreck-located-rv-petrel/
Yorktown was found in 1998.
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As an interesting side note
Note the condition of the found carriers compare to the condition of many found battleships and battlecruisers. Many of the of the wrecks of the found BBs and CCs are in several pieces due to magazine explosions.
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The Lexington was also recently found.
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I had to double check as I thought that was found in Corpus Christi Not the same ship, but it took the name after the Lexington was lost.
https://en.wikipedia.org/wiki/USS_Lexington_(CV-16)
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I had to double check as I thought that was found in Corpus Christi Not the same ship, but it took the name after the Lexington was lost.
https://en.wikipedia.org/wiki/USS_Lexington_(CV-16)
All US carriers sunk during the war had Essex class carriers renamed at some point during construction in their honor.
Yorktown CV-5 --> CV-10
Hornet CV-8 --> CV-12
Wasp CV-7 --> CV-18
Lexington CV-2 --> CV-16