Wednesday, December 11, 2013

Mad Props


Because we re-powered, we needed to find a new propeller that would better match the performance curve of our new Yanmar 4JH4-TE.  After hearing good things about Campbell Sailer props, and how they reduce drag when under sail, as well as prop-walk when under power, we decided to give them a try.  One of our friends at the marina has touted them to have reduced drag on his boat so much that he gets an extra half of a knot to a knot more under sail than when he had a traditional fixed prop.  The price for the Campbell Sailor is comparable to a normal Michigan propeller which made the decision all that much easier. We've heard from a lot of people that when they first get them they always wonder whether or not there was a mistake made and they were sent too small of a prop by accident, and funnily enough, we thought the same.  The difference is humorous, and with it installed, Moitessier looks like a fat man wearing a tiny hat.  Hehehe.  

My pretty Proppy garden

Before we installed it, Frank had to lap it to the shaft.  This process is better explained here. Basically, lapping fine tunes the fit between the shaft taper and the propeller, making a tighter tolerance fit.  After it was lapped, Frank sandblasted it with a sandblaster borrowed from a neighbor on a steel boat (God, I do NOT miss owning a steel boat!) then applied Interlux 2000 primer followed by 3 coats of Pettit Trinidad Hard Bottom Paint on both the prop as well as the shaft.  The thinking behind this is that hard paint holds up a lot better to the wear incurred on the prop.  We had inquired with the yard about their experiences with various methods of reducing prop fouling, and this is what they had suggested.  They say that they get 2-3 years on the large sport fishers doing a lot more motoring than we will.  Again, we'll see how it all works out.  

The fit before lapping.  The light areas are the only
 places of contact between the shaft and prop.
Lapping compound applied
Post lapping.  Smooth prussian blue=good fit :) 
Sandblasted prop
Primed with Interlux 2000 
Pettit Trinidad on and ready to go.

2 comments:

  1. Have you guys found the bottom paint on the shaft and prop working well? How do you like the performance of the sailor prop? PS- great writing!

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    Replies
    1. Hi Jon and Shannon,

      To be honest, it's too soon to tell whether or not the bottom paint is working well. In terms of the sailor prop, we have noticed a bit of a difference, in prop walk at least. Again, hard to tell as we repowered and didn't get much of an opportunity before re-powering to take the boat out so we're not sure about the difference before and after. Thanks for your compliments on the writing, and welcome to the blog :)

      Yu

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