Propeller choice

[Otto]

Hi, I recently purchased a Gemini semi rigid shallow hull rubber duck 5.3 meter with a autolube Yamaha 70. The prop is a 3 blade and when turning slightly to either side it cavitates badly. The boat is only used on inland dams. What do you suggest would be the best suited prop for this motor and boat. Tx

 

[Mieliepit]

Hi there.

I don't think changing your propeller is going to sort out your problem. I think that your motor is not deep enough in the water. You must chek that your cavitation plate on the motor is running just under the water. It must be more or less level with the bottom of your duck when trimmed down.

Regards.

 

[Pro-Duck]

I think you should make sure your motor is low enouch. I would also not worry about the amount of blades, but rather the pitch of the prop. Have a look on the prop if you have a 15" or a 17" prop. I think you have a 17" prop, that turns to fast when in less resistance(when turning) and looses grip to easily. The problem with a flat botoom is that you dont have enough hull in the water when you turn, it lifts out on the one side, pushing the motor to shallow.

Trim the motor right in to the stern, and see if it helps.