"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?