Rudder position with respect to prop

[Gary]

Can anyone provide me with some rules of thumb or reference sites that may help?

[BrettM]

Rule 1 -
Make the distance from the aft end of the propeller shaft to the leading edge of the rudder greater than the length of the propeller Boss! It has happened...

[victor]

Metal Marine Pilot of Tacoma, Washington will specifiy what your rudder should look like and where it should be positioned if you send them drawings of your vessel and some other general information. I assume they have a web site. They do not charge for this service, or at least they didn't used to.

[Polarity]

.. and if you offset it slightly you can get the shaft out /in without removing the rudder...

A quick tip: it would probably help people give good answers if you gave a little more info. eg sail ,power, 5 knots or 50, yacht or ship etc

[Gary]

Originally posted by Gary
Can anyone provide me with some rules of thumb or reference sites that may help?

The boat is 11m (aluminium) in length with a top speed of 28 knots. Power plant is a 3216B CAT 450hp. The boat currently walk sideways considerabaly to port when reversing. Steerage to Starboard almost non existant.

The rudder currently is very close to the prop.

[Stephen Ditmore]

I don't have time to go look it up right now, but Donald Blount wrote on powerboat rudders in a recent issue of Professional BoatBuilder Magazine.

www.proboat.com

Blount and many others do not locate the rudders directly in line with the props/shafts.

On twin installations a little toe-in helps (if you don't have the steering geometry that turns the rudder on the inside of the turn more than the rudder on the outside).