I have the smaller 34R with a 27Hp diesel.  The transmission is slightly above 
2:1.  I have a 15" two blade prop and set it to 18 degrees, I think.  The 
setting from PYI when I got the prop was a little aggressive and I dropped it 2 
degrees.
 
If I let the bottom get horrible, the first sign is slow speed and wiping off 
the scum makes a huge difference.  Generally I can get good speed with a clean 
bottom up to about 6.6 at 2800 rpm.  I get better speed sailing, as the two 
blade lacks area to really push the hull. Compared to similar boats, I got the 
wrong prop and a 16" would have been better for my boat.  The two blade is 
preferred for racing, as you can set the blades vertically and decrease the 
drag.
 
Based on your email, I think you lowered the pitch rather than increased it.
 
Chuck Scheaffer, Resolute 1989 C&C 34R, Magothy River, Md
 
 
 
  

> On 08/20/2025 4:10 PM EDT rockland bazemore via CnC-List 
> <[email protected]> wrote:
>  
>  
> Wondering what setups you all have with this configuration. 
> We have a newer 16" Maxprop (I never measured) with recently adjusted to 14º 
> pitch based on Rob's 37+ setup. He does a lot closer to hull speed.
>  
> When we left for our trip in Annapolis we could do 5.2kn. The bottom was 
> cleaned about 3 weeks prior. 
> I changed the pitch to 14º in Block Is. 
> Couple weeks later and now we only do 4.2kn in slack water. 
> The bottom doesn't seem to be THAT bad. The prop and shaft are very clean.
> I'm wondering now if its possible transmission slipping? The ATF oil smells 
> fine. 
>  
> Gear ratio 2.14 Prop shaft 1-1/8"
>  
> Ideas?
>  
> --
> Rockland Bazemore
> S/V Blue Pearl
> C&C 37/40+
> Annapolis, MD
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