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Paladin Paladin is offline
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First recorded activity by BoatBanter: Aug 2006
Posts: 188
Default Useless propeller


"Gilligan" wrote in message . ..
|
| "Paladin" noneofyourbusiness.www wrote in message
| ...
|
| "Gilligan" wrote in message
| . ..
| | The propeller does boil the water. It is a scientific fact and I shall
| offer
| | irrefutable proof:
| |
| | http://www.brooklyn.cuny.edu/bc/ahp/MBG/MBG4/Joule.html
| |
| | Quotes:
| |
| | "In the following years he took to measuring the amount of heat
| generated by
| | every mechanical process he could think of. He enclosed wooden paddles
| | inside an insulated container and used a falling weight to turn a shaft
| and
| | churn the paddles. Friction caused the water in the container to heat
| up,
| | and Joule measured the heat change. From this the work done could be
| | compared with the amount of heat that had been produced.
| |
| | By 1843 he was ready to publish. Called the mechanical equivalent of
| heat,
| | this is value for the amount of work required to produce a unit of heat,
| and
| | is calculated as 41,800,000 ergs. (One erg is the work done in moving a
| one
| | gram mass through a one centimeter distance)."
| |
| |
| |
| | So, as one can plainly see that in the mid-1800's it was recognized that
| the
| | churning of propellers heat the water. In the case of the cavitating
| | propeller, the slippage is so great that the energy that would normally
| go
| | into propelling a great ship forward goes, instead, into raising the
| caloric
| | content of the fluid medium surrounding said propeller causing boiling
| and
| | cavitation.
| |
| | Hence, the propeller boils the water, causing cavitation.
| |
| | My tea kettle has a propeller in it and boils water quite quickly with
| no
| | application of heat.
|
|
| I'm not denying that mechanical energy applied to water will cause
| its temperature to rise but it doesn't cause it to boil in the case
| of a yacht's propeller. There isn't enough energy outputted to any
| ship's propeller that can cause the ocean around it (and cooling it) to
| boil.
| No, it isn't the boiling of water that causes cavitation. It is the
| lowering
| of pressure that causes the water to vaporize.
|
| The very chart to which you posted a link proves this to be true.
| http://encarta.msn.com/media_4615415...for_Water.html
| It shows there are a couple ways to skin a cat. Water can
| be vaporized by adding heat, or by lowering pressure. A prop might
| add a tiny bit of heat but it subtracts great amounts of pressure.
| It is the subtraction of pressure that causes cavitation.
|
| Ready to say UNCLE yet?
|
|
| I can tell I am battling against a person of towering intellect who does not
| back down when guided by the light of truth.
|
| I must give in and say Uncle.
|
| Who is this man so knowledgeable in the ways of science?
|

And, it's a rare pleasure to meet a man who's willing to learn and
admit his (very rare) mistakes. But, I suppose you're as learned
as you are because you're willing to consider alternate views
with an open mind as well as a fondness for language as a tool
and a standard. (unlike the likes of DSK). I'm willing to bet
you're either a libertarian or a staunch Goldwater conservative.

One must wonder. Does the faulty use of language produce a
liberal or does liberalism result in a faulty use of language...

Paladin

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