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Post by OziRiS on Jul 19, 2015 10:58:20 GMT
Testing the expression "blowing them out of the water", both in its literal sense and the metaphorical version where it means that you've won overwhelmingly over your adversary.
The literal test: Find out if a mine or torpedo could actually blow a boat out of the water without destroying it.
The aim was to place a bomb under a boat, set it off and get it to lift the intact boat off the surface of the water and have it land again relatively intact.
The myth seemed to have some merit in the small scale test in the shop where they placed a small model boat in a tank of water and set off a cherry bomb underneath it. When the cherrybomb was placed directly under the surface, the boat was blown to bits, but once the charge was placed deeper in the water, halfway between the bottom and the surface, lift was actually achieved. This came to serve as the reference point for the full scale test.
The full scale test was conducted in the well known quarry lake that's been used in previous tests. A rather large boat with a steel hull was tethered in place in the lake, a line was secured to the bottom, so the bomb could be secured directly below it and then the bomb was made. A plastic septic tank filled with 1,500 pounds of sand and 1,000 pounds of ANFO doubled as an underwater mine. When it (finally) went off, the boat was completely destroyed and the myth called "Busted". (I expect discussions about this result.)
The metaphorical test: In the Breaking Bad series finale, hero Walter White, anticipating a meeting with the bad guys, rigs an M60 machine gun in the trunk of a car. The rig is set up so that when he presses his key fob, the trunk springs open and the M60 fires all 150-200 rounds in its box magazine on full auto in a sweeping motion from side to side, killing everyone in the building, except Walter, because he knows what's coming and dives to the floor to save himself. Epic win!
In the show, Walter is seen building the rig out of parts that are readily available in stores around a regular small town. The swivelling stand is made from the base of an office chair, the motor that powers the action is a garage door opener and the trigger mechanism is made from small actuators used to open and close car windows.
The first part of the test was to see if a rig like that could even be built from the parts shown in the show. Apart from Adam having to put in some bicycle chain and gears between the garage door opener and the gun, because the motor was moving way too fast, the rig shown in the show actually held up. And, as Adam noted, the bicycle chain and gear was something Walter could easily have gotten hold of, so even though it wasn't part of the rig in the show, it was still well within the spirit of the myth.
The second part was actually getting the rig to work and although the grouping of the bullet holes in the wall wasn't as pretty as it was in Breaking Bad, the concept certainly worked! After a few mishaps with stuff stuck in the barrel, everything went off without a hitch in the third try. The gun fired all the rounds in the magazine, the wall was riddled with bullet holes, the bad guys standing up inside the building were all dead and Walter lying on the floor didn't have a scratch on him.
Awesome build, awesome execution and a final verdict of "Plausible".
Sidenote: The new visual style of the show works really well, both with the more cinematic way of shooting it and with the on screen data provided about the myth and the scientific elements that go into it. In my opinion, all of our fears about the new format have been put to shame.
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Post by ironhold on Jul 19, 2015 23:16:18 GMT
Do you know if this episode will get a repeat?
Yesterday was all sorts of hectic, and so I forgot that it was even going to be on.
Thanks.
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Post by OziRiS on Jul 19, 2015 23:40:12 GMT
Do you know if this episode will get a repeat? Yesterday was all sorts of hectic, and so I forgot that it was even going to be on. Thanks. Not a clue. Remember, I'm not in the US, so let's just say I don't get the episodes on my TV and leave it at that  |
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Post by the light works on Jul 20, 2015 0:00:50 GMT
I would quibble with the interpretation of the first myth. my interpretation would be that the boat leaves the water, with no other restrictions on condition.
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Post by OziRiS on Jul 20, 2015 1:11:14 GMT
I would quibble with the interpretation of the first myth. my interpretation would be that the boat leaves the water, with no other restrictions on condition. I would quibble with the interpretation of the result. The myth didn't originate in a 60 foot deep quarry lake, but on the open ocean. Placing a 1,000 pund depth charge only 30 feet under the boat and with only an additional 30 feet between the charge and the bottom would equate to "not meeting the circumstances of the myth" in my book. I know they can't go out and do this on the open ocean, but they could've at least taken into consideration that not many places in the open ocean - or even in harbors for that matter, which mines were often employed to protect - are only 60 feet deep and could have adjusted the size of the charge accordingly. I think they should have gradually scaled up their small scale test to see at which point the depth of the body of water and the size of the charge would suddenly stop producing the result they saw in the shop test. Maybe halfway between bottom and surface only works with a boat of a certain size, a charge of a certain size and a body of water of a certain depth. Basically what I'm saying is, if you have an initial proof of concept in small scale, but your large scale version doesn't produce the same result, there's a good chance you just messed up some proportions as you scaled up. The fact that you might be able to hold a 2 inch toothpick of a certain shape and thickness between your fingers and have that hold up a quarter pound of weight doesn't necessarily mean that the shape/thickness to weight/center of mass ratio scales up in a linear way if your stick goes from 2 inches to 2 feet. |
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Post by the light works on Jul 20, 2015 2:26:57 GMT
I would quibble with the interpretation of the first myth. my interpretation would be that the boat leaves the water, with no other restrictions on condition. I would quibble with the interpretation of the result. The myth didn't originate in a 60 foot deep quarry lake, but on the open ocean. Placing a 1,000 pund depth charge only 30 feet under the boat and with only an additional 30 feet between the charge and the bottom would equate to "not meeting the circumstances of the myth" in my book. I know they can't go out and do this on the open ocean, but they could've at least taken into consideration that not many places in the open ocean - or even in harbors for that matter, which mines were often employed to protect - are only 60 feet deep and could have adjusted the size of the charge accordingly. I think they should have gradually scaled up their small scale test to see at which point the depth of the body of water and the size of the charge would suddenly stop producing the result they saw in the shop test. Maybe halfway between bottom and surface only works with a boat of a certain size, a charge of a certain size and a body of water of a certain depth. Basically what I'm saying is, if you have an initial proof of concept in small scale, but your large scale version doesn't produce the same result, there's a good chance you just messed up some proportions as you scaled up. The fact that you might be able to hold a 2 inch toothpick of a certain shape and thickness between your fingers and have that hold up a quarter pound of weight doesn't necessarily mean that the shape/thickness to weight/center of mass ratio scales up in a linear way if your stick goes from 2 inches to 2 feet. some things just don't scale. |
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Post by blazerrose on Jul 20, 2015 2:36:58 GMT
Do you know if this episode will get a repeat? Yesterday was all sorts of hectic, and so I forgot that it was even going to be on. Thanks. My DVR guide has it listed at 8pm next Saturday before the next new episode airs. |
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Post by tom1b on Jul 20, 2015 4:41:20 GMT
Their small scale test was poorly carried out. Black powder is a "low explosive." It doesn't produce a shockwave or a wave. By definiton, a low explosive burns, at a subsonic speed. The gas bubble created by their homemade cherry bomb created a bubble that was larger than their tank. It hit the front & back of the walls helping to displace water. ANFO can be a high explosive. ANFO has a wide range of detonation speeds. By definition, a high explosive produces a shockwave: it explodes, it detonates. Watch every episode they have ever used ANFO and you clearly see a shockwave on the high speed camera. 450lbs of ANFO demolished a garbage truck on their show and they wanted to put 1500lbs under a ship? I always go back to the 1947 Texas City disaster. 2300 TONS of ammonium nitrate exploded on the Grandcamp. A 2 short ton anchor was blown 1.62 miles away and found in a 10ft crater. People 10 miles away were dropped to their knees by the explosion. It knocked 2 sightseeing planes out of the sky. It registered on seismographs in Denver, Colorado. More importantly, it created a 15ft tidal wave that went inland too. The tidal wave portion that went out to sea almost made it 100 miles. This 15ft tidal wave lifted a barge, The Longhorn II, out of the water and pushed it inland. This pic (it's not a great pic but it's the only one I could find) shows where all the ships were docked. Longhorn II inland 1Longhorn II inland 2Longhorn II inland 3Count it or don't count it but an explosion created a wave that "blew it out of the water." |
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Post by WhutScreenName on Jul 20, 2015 15:09:28 GMT
I was just happy to see a new episode. In addition, I enjoyed the Trunk Gun myth quite a lot.
The boat one was interesting, and fun to watch as well. It was a little disappointing that they called it busted so quickly, but it did make for good TV
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Post by Antigone68104 on Jul 21, 2015 1:56:23 GMT
450lbs of ANFO demolished a garbage truck on their show and they wanted to put 1500lbs under a ship? According to the Wikipedia episode summary, it was 850 pounds of ANFO in the cement truck, and 1000 under the boat. Still more in the later test, but not as much difference as you're thinking. That said, I fully expect a revisit with a smaller amount of explosives. A friend of mine insists she's seen WWII newsreel footage of a ship being lifted by an explosion without breaking, but I don't recall seeing that and she doesn't have a video link. I was never a huge Breaking Bad fan, but I checked out the final episode via a combination of TV Tropes and YouTube, and I think they did a good job on the build and the test. And if Walt could get his hands on a M60, he could probably get his hands on a couple belts of blank ammo to test his rig first  . |
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Post by silverdragon on Jul 21, 2015 8:16:07 GMT
 Heh heh heh... light the blue touch paper and retire to a safe distance.... You all know I am going to play devils advocate. I say result "Proven" by someone else. Blow.... definition... blow as in wind. In that sense, Sir Christopher Cockerell, and he is a "Sir" there for his very idea, "blew" a vehicle out of the water, during the 1950's. Yeah, he invented the Hovercraft... and thats a fan that blows with a BIG force?.... .... stands back and awaits the cries of indignation on "thats not the true sense of the thing".....  But hang on a moment. In the proof of concept, they managed to scale it down, and sort of half prove the idea. Then with a LOT of explosives, they managed to over-do it in fine Mythbusters style. I do not decry the testing method, we all want BIG boom..... But... A Smaller charge?... A Better hull?... Take a mine-sweeper. I know they have a stronger hull than some other boats. Take the progress in anti land mine personnel transport vehicles... they went from basic landrover to highly armoured underneath vehicles in the war on terror in Afghanistan. If this had been a naval thing, and they were to re-investigate how to deal with sea mines, how strong can you make a hull?.... Would it be resistant to current (Or past) water born mines?.. They can float a tank, and Tanks can run over landmines cant they?... |
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Post by the light works on Jul 21, 2015 13:52:23 GMT
450lbs of ANFO demolished a garbage truck on their show and they wanted to put 1500lbs under a ship? According to the Wikipedia episode summary, it was 850 pounds of ANFO in the cement truck, and 1000 under the boat. Still more in the later test, but not as much difference as you're thinking. That said, I fully expect a revisit with a smaller amount of explosives. A friend of mine insists she's seen WWII newsreel footage of a ship being lifted by an explosion without breaking, but I don't recall seeing that and she doesn't have a video link. I was never a huge Breaking Bad fan, but I checked out the final episode via a combination of TV Tropes and YouTube, and I think they did a good job on the build and the test. And if Walt could get his hands on a M60, he could probably get his hands on a couple belts of blank ammo to test his rig first . in the 80s, naval doctrine for sinking enemy ships was to blow the water out from under the middle and let the boat crack under its own weight. unfortunately, at the time, legend had it the Russians made their entire hulls out of titanium, and the ship could rest on bow and stern indefinitely without breaking. |
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Post by watcher56 on Jul 22, 2015 3:51:00 GMT
Finally got to watch this episode last night.
The 'Breaking Bad' portion was not a myth, simply an engineering challenge.
The 'Blow It Out of the Water' was so flawed (see above) as to make any results non-sequitur.
Jumped the shark, the Mythbusters have.
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Post by the light works on Jul 23, 2015 3:35:11 GMT
well, in addition to fighting a fire during the episode, there was also a power outage that meant only half got recorded.
fortunately, it's the second half.
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Post by mrfatso on Jul 23, 2015 8:05:47 GMT
I would agree with many facts already motioned in this thread about the test,.
1) The myth was about ships much larger than the boat used in the test some of which would have been armoured warships.
2) The behaviour of explosives in deep water is interesting I know that when you analysis a a Seismic data chart taken from explosives charges used in water you have to allow for multiple mirroring effects. The some of shockwaves travel through the water down to the rocks below, but others will reflect off the surface and back down causing false horizons on the trace as some of the waves were absorbed by the rocks and others bounced upwards again this can happen several times as the shockwaves lose energy. We used to have to work out if a feature we saw on the trace was a real horizon in the strata or another reflection of the sea floor. ( no doubt computers now do this automatically) . These were seismic tests done in the open ocean, the amount of reflection of the shockwave that would occur in a tiny lake would be huge.
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Post by mrfatso on Jul 23, 2015 8:18:32 GMT
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Post by silverdragon on Jul 23, 2015 9:44:46 GMT
I am agreeing with MrF [above] on the explosive bits.
I also agree with some of the findings of the show.
The explosion, lets look at that.
In the initial part of the explosion, deep water or not, it forms a bubble, almost the shape for want of illustration, a balloon.
The idea that as soon as that breaks the surface, it will self implode through that break and collapse sending a straight force of energy straight upwards, yes, its the same as that balloon being allowed to deflate through the valve.
At that depth and at that amount of explosives.
However, unless its a new type proximity mine that can "sense" a boat above it?...
The myth comes from much earlier than that, and all mines and torpedo's of that ear would have been contact detonated.
1,000 lbs of anfo?... Overkill.
Jumped the shark?... they set an Australian surfer on it, and this shark was only a tiddler?...
As for what happens during an explosion.
This below is well worth a watch... its dry ice/nitrogen, but, the physics of an underwater deep sudden expansion are almost exactly the same, whatever the scale.
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Post by Cybermortis on Jul 23, 2015 11:15:46 GMT
The claim that torpedoes could blow a ship out of the water dates to WW2, or at least that is the date when the expression seems to have come into general use. It may, as many saying do, have come from a slightly earlier period and I have run across the saying in relation to ships in the 1700's. However those references were written post-WW2 so it is unclear as to if 'blown out of the water' was actually a phrase added by an author when writing about those things.
In WW2 the largest torpedoes carried a thousand pound warhead, those interestingly were Japanese torpedoes. Which might have been because the Japanese (unlike other nations) designed their Submarines to be part of their Battle fleets, and they were intended to attack the US Battleships directly. As such they would have needed as big a torpedo as could be carried...which as it turned out was very large as the Japanese produced some of the largest Submarines of the period.
As far as warship design goes the hull was not armored all the way down. Apart from the cost, the biggest reason for not armoring all of the hull was the weight this would add.
The fact is that no ship has the strength of hull or thickness of armor to survive any explosion powerful enough to lift it out of the water without being blown apart.
The accounts of ships being lifted out of the water are most likely a result of an optical illusion. We'd be talking about ships considerably longer than what MB used, probably at least three times the length, but an explosion of the same size or smaller. So what people would have been seeing would be the cavity created by the blast under part of the ship, then the upward spray. This would make it seem as if the ship had been lifted up out of the water, or part of it had been, especially if the explosion broke or bent the keel upwards.
As an aside. Titanium was used in the construction of some Soviet submarines, and may well have been used for surface ships as well. However this has nothing to do with strength; Titanium is not stronger than steel, its just lighter for a given volume. It would have been chosen because it is more resistant to salt water corrosion and is not magnetic (hence wouldn't set off magnetic mines or be detectable by magnetic sensors).
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Post by silverdragon on Jul 23, 2015 11:35:07 GMT
Scale...
Can we look at smaller lighter (or not) heavily armed things such as PT boats.
And on that, I know some PT boats were all wooden conversions from faster speed boats used before the war...
However, as I already have experience of wave hopper speed boats with very strong hulls that can withstand a drop of 20ft off a waive, with a smaller explosion?....
Perhaps a small boat moving "at speed" my even take off when hit by a waive created by the blast wave of an explosion?...
We have been assuming the ship in question was NOT moving when the blast hit.
Is that an error?...
Also, Submarines.
They have a thick skin dont they?..
I know of several cases where a submarine has had to make a sudden emergency surface move.
There is famous imagery used by NCIS...
Could a depth charge under a sub which is at periscope depth make it jump out of the water?... at speed?...
Depth charge then because of damage an emergency "blow" as its called?...
To anyone watching, that would sort of fit the explanation "we blew it out the bloody water" wouldnt it?...
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Post by Cybermortis on Jul 23, 2015 11:52:47 GMT
You didn't use torpedoes at motor patrol boats, and certainly not at targets moving at 20+ knots. (They'd be too small a target and moving too quickly to target with a torpedo, which would have been fired from no less than around 500 yards).
Submarines would not have been at periscope depth anywhere near ships with depth charges.
Top underwater speed of submarines in WW2 was between 5-8 knots on average. Keep in mind that they were using electric motors unless surfaced.
WW2 terminology regarding depth charge attacks for both the British and American navies used 'forced to the surface' or 'blown to the surface'. I've never once run across 'blown out of the water'.
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