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Kaleun1961
02-14-2008, 08:14 AM
While doing some searching about underground nuclear testing, I came across a YouTube video of a conventional depth charge detonation. I don't know the TNT equivalent of this depth charge, but it's a big sucker. If the Allies had one this powerful during WW2, I don't think the U-boats would have been quite so deadly as they were.

Any former naval personnel here who wish to comment and provide their knowledge of modern depth charges?

Depth Charge Detonation (http://www.youtube.com/watch?v=1flVlL4Mf8k&feature=related)

Celeon999
02-14-2008, 08:23 AM
Thats not a depth charge. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif


Its a sunken barge from ww2 laden with explosives which they found and neutralized in a controlled detonation. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif


Just today i saw a article on the german navy website stating that yet another anchor mine from ww1 or 2 has been located and destroyed by a german minesweeper.

The article is in german but you can see some photos here : www.marine.de (http://www.marine.de/portal/a/marine/kcxml/04_Sj9SPykssy0xPLMnMz0vM0Y_QjzKLNzKO9zYLBclB2SH6kX DRoJRUfW99X4_83FT9AP2C3IhyR0dFRQAz_uaJ/delta/base64xml/L2dJQSEvUUt3QS80SVVFLzZfMjNfUUxN?yw_contentURL=%2F 01DB070000000001%2FW27BSH2W743INFODE%2Fcontent.jsp )


It was not a immidiate threat for the shipping routes but definitely for fishing ships.

Kaleun1961
02-14-2008, 10:07 AM
Aaah! I thought it was rather powerful for a "depth charge." I was also curious why the ship in the film wasn't under way. I'm used to seeing a destroyer roll a wabo off the stern and keep on going, so as to escape the blast. The language in the video isn't English, so I had no idea what was being said. Obviously, you can't just look at a YouTube title and believe its accuracy.

Foehammer-1
02-14-2008, 10:42 AM
Speaking of nuclear, can someone please explain to me what's going on in this video?
http://www.youtube.com/watch?v=MRC5KDqpZ_I&feature=related

I mean, the nuke goes off underwater, makes a mushroom cloud. Then, for a few second, this white sphere develops out of thin air, then disappears from the bottom up, leaving just the mushroom. Is that steam? If so, then why doesn't it develop immediately along with the initial explosion? And why disappear so fast?

I assume that the shockwave pushed water out first, cause water doesnt compress. Then the heat energy got to the surface and evaporated tiny water droplets. But am i right? I'm only in 1st year, and we didn't get beyond potential and kinetic energies, and conservaion of momentum, so far, in physics...

And since we are on topic, here's another vid i found. Lol http://forums.ubi.com/images/smilies/88.gif Idiot (http://www.youtube.com/watch?v=tBslqsP5UJw&feature=related)

Celeon999
02-14-2008, 10:47 AM
Originally posted by Kaleun1961:
Aaah! I thought it was rather powerful for a "depth charge." I was also curious why the ship in the film wasn't under way. I'm used to seeing a destroyer roll a wabo off the stern and keep on going, so as to escape the blast. The language in the video isn't English, so I had no idea what was being said. Obviously, you can't just look at a YouTube title and believe its accuracy.


The name of the video and the description are contradictory anyway. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

The description contains the real explanation.... Propably http://forums.ubi.com/images/smilies/blink.gif

Anyway, its one huge bang ! http://forums.ubi.com/images/smilies/59.gif

Celeon999
02-14-2008, 11:16 AM
Originally posted by Foehammer-1:
Speaking of nuclear, can someone please explain to me what's going on in this video?
http://www.youtube.com/watch?v=MRC5KDqpZ_I&feature=related

I mean, the nuke goes off underwater, makes a mushroom cloud. Then, for a few second, this white sphere develops out of thin air, then disappears from the bottom up, leaving just the mushroom. Is that steam? If so, then why doesn't it develop immediately along with the initial explosion? And why disappear so fast?

I assume that the shockwave pushed water out first, cause water doesnt compress. Then the heat energy got to the surface and evaporated tiny water droplets. But am i right? I'm only in 1st year, and we didn't get beyond potential and kinetic energies, and conservaion of momentum, so far, in physics...

And since we are on topic, here's another vid i found. Lol http://forums.ubi.com/images/smilies/88.gif Idiot (http://www.youtube.com/watch?v=tBslqsP5UJw&feature=related)


Interesting question. I find it interesting that there is a mushroom cloud at all.

On land , a mushroom cloud only forms when the bomb detonates at low altitude.

Through the released energy, the air at ground zero turns into plasma which is emitting photons. That is the flash you see at detonation. (70% to 80% of the whole bomb's energy is released through these photons)

(No flash in this video as the enery is released within water instead of air, so no photon emitting plasma)

It disappears right away as the plasma gets cooled down considerably in the next seconds after the detonation.

In the negative overpressure phase that comes after the shockwave (positive overpressure phase) the air streams back into the center of the detonation to fill the vacuum there.

Cold air pushes the hot air upwards as it takes its place and so the warmer air begins to rise.

This creates a suction effect which sucks soil, debris , trees, simply everything upwards forming a pillar made up of steam, smoke, gases and debris. (Several hundred meters per second)

As this pillar cooles down on its way upwards it looses speed while the faster lower sections push into it pressing the entire upper section outwards. This creates the mushroom shape.


Somehow this must be similar in this subsurface detonation with the difference that we see water, steam and propably soil from the sea floor forming this cloud. I doubt that it rose very high compared to atmospheric low level detonation.

Water is a much better heatconductor than air so the seawater cools everything down again much faster.

The white stuff you wonder about is simply seawater that got turned into steam and is evaporating now as it has lost enough heat to do so.

(Thats why it isnt there right from the beginning)

Take a look at other nuclear test footages. You will notice that the clouds change their color in different phases of their rise but always turn completely white in the end due to evaporation of steam.

bunkerratt
02-14-2008, 12:40 PM
http://forums.ubi.com/images/smilies/blink.gifwow....as an addon to the topic if you ever watch old test footage of atomic weapons tests you will see white vertical lines of smoke on each side of the mushroom cloud ...they are marker rockets placed at"x" number of meters distance away from ground zero...

Kaleun1961
02-14-2008, 12:43 PM
Originally posted by bunkerratt:
http://forums.ubi.com/images/smilies/blink.gifwow....as an addon to the topic if you ever watch old test footage of atomic weapons tests you will see white vertical lines of smoke on each side of the mushroom cloud ...they are marker rockets placed at"x" number of meters distance away from ground zero...

I never knew that! I thought those were shock waves. So, they fired rockets vertically in order to provide visible indicators of the size of the explosion? Fascinating!

Celeon999
02-14-2008, 12:52 PM
Originally posted by Kaleun1961:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bunkerratt:
http://forums.ubi.com/images/smilies/blink.gifwow....as an addon to the topic if you ever watch old test footage of atomic weapons tests you will see white vertical lines of smoke on each side of the mushroom cloud ...they are marker rockets placed at"x" number of meters distance away from ground zero...

I never knew that! I thought those were shock waves. So, they fired rockets vertically in order to provide visible indicators of the size of the explosion? Fascinating! </div></BLOCKQUOTE>

Yep, as you exactly know how far these rockets travel within one second, you can later look at photos and use the length of these smoke trails in connection with the cloud next to them to determine its size and speed of rising.


You can learn all this stuff by playing the great Fallout series http://forums.ubi.com/images/smilies/25.gif

"America's first choice of post-thermonuclear war simulation" like stated on the website of Fallout 3 http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Fallout 2 Intro (http://www.youtube.com/watch?v=_mcJAI6oRYY&feature=related)

Fallout 3 Teaser Trailer (http://www.youtube.com/watch?v=Lf4JsRQFhQo) (I cant wait) http://forums.ubi.com/images/smilies/heart.gif

bunkerratt
02-14-2008, 12:53 PM
yeah..expansion rates and many other things