"Brian Whatcott" wrote in message
...
On Wed, 19 Mar 2008 12:07:00 -0400, Dr. Di
wrote:

I didn't measure the differences in shaft speed, mainly because I have
no way to do it.. But the transmission overheats, and the boat speed
through the water decreases without any change in engine RPM's..
/snip/

These days, non-contact or optical tachometers are cheap - and popular
items at hobby shops. Look at this one, for example. $28.
Stick a piece of tape on the shafdt and have the tach look at it.


http://h1070530.hobbyshopnow.com/products/description.asp?prod=HAN156

Brian Whatcott Altus OK

Sounds interesting, but why does it care how many blades are on the
propeller if it is only looking at the shaft?