"Peter" wrote in message
oups.com...


Cavitation is caused by the prop spinning too fast for the forward
motion of the vessel.

Cavitation is caused by water not being able to move fast enough to fill low
pressure spaces created around such things as a propeller. A spinning disc
has no forward speed regardless of RPM yet there is no cavitation. A
propeller is a rotating wing and the low pressure side causes the water to
"boil", hencce the creation of cavitation. Higher RPM gives higher
tangentail blade speeds and greater pressure differential between the faces
of the prop.