Prop clearances/distance. Two questions.

[Darren Kinvig]

   Can someone clear up these clearances/distances for me.   What is the recommended clearance from the prop to the underside of the hull.  Also. I have a transom mounted rudder. I understand the idea of having enough clearance from prop to rudder to change the prop without removing the rudder. What is the distance from the prop to the face of transom. Is there a Min. that should be observed?  Will there be cavitation issues if the prop is too close to the face of transom?

 

 thanks

Topic

[Darren Kinvig]

Min. Clearance.

     Ventilation?  is this a condition where air can enter the prop wash/ prop from the end of transom into the prop? Looking at some drive examples where props on some boats appear to be close to the face of the transom, I have seen that the transom has been extended in the area above the prop. Is this a solution to prevent Ventilation?

   Thanks for your advice and knowledge.

[Woo]

10% of the prop diameter is considered the minimum clearance between prop and hull bottom.

I feel the answer to your 2nd question may be vessel specific, and you may be more concerned about Ventilation rather than Cavitation?

1 user thanked author for this post.

Tony Athens

[Darren Kinvig]

Min. clearances

    Thanks for the pictures Tony.

Unfortunately it is -49F here at the moment. Not able to set the shaft and rudder in/on the boat for a picture.  I hope the text and lines in these pictures will make better sense.

 

 

[Tony Athens]

How about posting good pics what what your are trying to make us envision.. No one here has a crystal ball..    

[Author]

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