prop guru question
 

What effect will adding rake to a prop have on the attitude of the boat?

More bow lift.

Yes bow lift.

Too much rake when not needed can be a performance deterrent as well due to drag.

Brett

I was looking for 200 more rpm, which I got from additional thinning of the blades. I also asked if anything could be done to help with a slight porpousing issue on calm water. I believe my prop guy added a bit of rake to the blades. It had a very adverse reaction. The boat seems like it is glued to the water and wants to bow steer. If I trim to the sky to lifft the nose, steering is really loose almost to a point were it's not safe. I haven't spoken to the prop guy directly to ask him what he did (he went away for a few days) I dropped the prop back at his shop and I hope to talk to him soon. I should have left well enough alone. It performed well but of course well is not alway good enough. Do you think that adding too much rake would have this effect?
(I may be mistaken about adding rake, but I think that is what was done) I think cupping would have been a better choice, but I'm not exactly an expert on prop science.

Thanks
Ray

Who did the prop ?

Bow steering issues would be the opposite of adding rake. Sounds like you went backwards.

Brett

That's exactly what I'm thinking. I was a bit thrown by philms response to my question. It's almost like negative rake if there is such a thing.




The work was done by a reputable shop. I'd rather not say who, but he has done work for me in the past with great results. Possible a misunderstanding of what I was trying to achieve.

They can certainly take rake out of a prop (to a point). Most rake that has been added into a Bravo style prop is added with cupping to the trailing edge anyway.

I'm still waiting to speak with my guy and ask him what was done. I'll post when I hear from him.

We put a slight bend in the blade tips as well.

Brett