"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?

Paladin

--
Posted via a free Usenet account from http://www.teranews.com

"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?

"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

--
Posted via a free Usenet account from http://www.teranews.com

Paladin,

You've getting close but your not there yet. If we are using the same
prop, driven by the same engine, at the same RPM's under normal
conditions without cavitation; then why does cavitation happen to the
system in foul weather?

I think that, just maybe, you are about to learn something; along with
some others(g) The graph will show it, if you you can figure it out.
THINK FIRST and then prove you thought with the graph.

Again I'll say Bye, Bye and I'm sorry I didn't keep my word and stay out
of the discussion




http://community.webtv.net/tassail/ThomPage