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She decided the tests were stupid.


Harold Jones
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12 hours ago, Ssnake said:

My friend at TKMS naval engineering has a much less favorable view on the implications, R011. This may very well lead to extensive yard time for some boats.

No wonder, if they need to retest all the affected steel. I think usually you have to cut out a test specimen to do one of those tests, but I am no expert on the matter.

A possible procedure is explained here: http://www.navweaps.com/index_tech/tech-037.php

Edited by sunday
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2 hours ago, shep854 said:

I wonder if her tune would change if she rode a sub to test depth, watched the string sag and listened to the ship groaning?

I think that one needs to be able to imagine the risk to others that arise as a consequence of your actions. It should be clear to anyone who has observed people at all for a few years that analysis of potential consequences does not often factor into peoples' thinking. Just look at how many people can't live within their means when they earn enough to do so, and the appalling risks taken by people to save a few seconds in traffic.

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7 hours ago, RETAC21 said:

I would say the steel hasn't been tested in real life to the conditions of the test, but these are not outlandish, -100 F comes to -38C  which is a temperature that is not uncommon in the Arctic. A collision or an impact may have significant consequences for those inside the people tank, and subsafe was written in blood, those of the crewmen of the Thresher and Scorpion.

Minus 100 F is Minus 73 C.  You're thinking of Plus 100 F.  The Arctic Ocean, the coldest place a sub can operate, doesn't get that cold.  The air temperature rarely gets below Minus 40 C/Minus 40 F while the water temp is above zero/Plus 32 F - or it would be ice.

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3 minutes ago, R011 said:

Minus 100 F is Minus 73 C.  You're thinking of Plus 100 F.  The Arctic Ocean, the coldest place a sub can operate, doesn't get that cold.  The air temperature rarely gets below Minus 40 C/Minus 40 F while the water temp is above zero/Plus 32 F - or it would be ice.

You are absolutely right indeed.

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1 hour ago, DB said:

I think that one needs to be able to imagine the risk to others that arise as a consequence of your actions. It should be clear to anyone who has observed people at all for a few years that analysis of potential consequences does not often factor into peoples' thinking. Just look at how many people can't live within their means when they earn enough to do so, and the appalling risks taken by people to save a few seconds in traffic.

Always remember the Military Intelligence motto: We bet your life.

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5 minutes ago, RETAC21 said:

You are absolutely right indeed.

Mind you, it is nice to know there is a big margin of safety.  I'm sure they didn't decide on this temperature randomly, and there is a reason the company got fined and the tester faces jail.

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MIL-STD-810G goes into some (!) detail when describing environmental conditions, everything from temperature to pressure to vibration and such.

Here is what it says as a summary cold environmental conditions:

Quote

Cold and Severe Cold Climatic Categories. These areas include northern North America, Greenland, northern Asia, and Tibet. In the Cold Climatic Category, the temperature during the coldest month in a normal year may be colder than the Basic Climatic Category cold extreme of -32°C (-25°F). In the Severe Cold areas, the temperature during the coldest month in a normal year may be colder than the Cold Climatic Category extreme of -46°C (-50°F). Temperatures colder than -51°C (-60°F) occur no more than 20 percent of the hours in the coldest month of the coldest part of the area (northern Siberia) where temperatures as low as -68°C (-90°F) have been recorded. Because extremely low temperatures are not controlled by a daily solar cycle, they persist for a long enough period of time to cause materiel to reach equilibrium at extremely low temperatures.

You will note that the lowest temperature cited is for North Siberia at -68C. This is an extreme limit, and would not be likely to that experienced at sea because the sea moderates temperature extremes. It wouldn't be entirely impossible to approach that over icepack, I suppose.

Anyway, this MIL-STD doesn't explicitly define the limits required for US nuclear submarines because it acknowledges that certain environments warrant special handling. Nevertheless, I think it shows that the military does not think that the low temperature limit is outlandish.

Air temperatures for high altitude flight are frequently down below -50, and the coldest temperatures tend to be at the equator (once one gets high enough).

Edited by DB
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The test temperature and the expected extreme operating conditions do not need to align. For example one could include tests at extreme temperatures in order to better determine the temperate toughness curve, even if you are mostly concerned with toughness at more moderate temperatures. Or it could be there as a safety margin given variations in composition etc.

Edited by KV7
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1 hour ago, KV7 said:

The test temperate and the expected extreme operating conditions do not need to align. For example one could include tests at extreme temperatures in order to better determine the temperate toughness curve, even if you are mostly concerned with toughness at more moderate temperatures. Or it could be there as a safety margin given variations in composition etc.

Exactly.

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Makes me think of the engineer in Memphis that was supposedly checking the Bridge over the Mississippi. The SINGLE engineer, who more or less started phoning it in a few years ago and missed that big crack in the bridge structure. 

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