I've got the wrong prop!

[Ryan Turner]

I've been suspecting that my CD33 had been outfitted with the wrong prop for some time now. The engine's been running hot, I couldn't get even close to the maximum RPM under full throttle, and the engine was tending to blow black smoke. She's on the hard now and it's confirmed. The boat originally came with a 2-blade 14RH10. She's now got a 3-blade 14RH13. The general rule of thumb as I understand it is that if you switch to a 3-blade prop you should maintain the same prop diameter but decrease the pitch by 2. So I should have a 14RH8 3-blade prop if I want to go that way. Now what do I do? Have the prop repitched? Replace it? Go back to the 2-blade prop? I've still got the original 2-blade 14RH10 and it's in great shape. How much performance would I loose with the 2-blade prop? I kind of like the idea of reducing drag while under sail. The 2-blade prop gives you this but what do you pay for the benefit? Anybody got any thoughts?

Ryan Turner
s/v Zenobia
CD33 hull no. 100
Oriential, NC

[jim smiley]

Ryan,
I had the same experience w/ a 14 x 13 3-bladed prop on my CD33. The folks at Robinhood marine recommended a 13 x 11 prop, i bought one and things were much better.



smileyj@cofc.edu