HI!
I HAVE A CD28 SAILBOAT WHICH HAS A 2 BLADE 13 X 13 SAILOR PROPELLER
ON IT AND I WOULD LIKE TO REPLACE IT WITH A 3 BLADE PROP.
WHAT SIZE HAVE OTHER OWNERS FOUND TO BE THE BEST CHOICE FOR A
THREE BLADE PROP?
RLINCOLN@BICNET.NET
PROPELLERS
Moderator: Jim Walsh
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Tom
Re: PROPELLERS
</LI>
TomCambria@mindspring.com
What engine do you have? It sounds like you may be way over-propped. Can you reach the rated RPM with the current prop in calm water? Any black smoke out exhaust?HI!
I HAVE A CD28 SAILBOAT WHICH HAS A 2 BLADE 13 X 13 SAILOR PROPELLER
ON IT AND I WOULD LIKE TO REPLACE IT WITH A 3 BLADE PROP.
WHAT SIZE HAVE OTHER OWNERS FOUND TO BE THE BEST CHOICE FOR A
THREE BLADE PROP?
TomCambria@mindspring.com
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Ryan Turner
Assuming you're correctly propped now...
</LI>
the general rule of thumb as I understand it is to drop two inches of pitch when you go from a two blade prop to a three blade. In your case you'd go to a 13X11 three blade prop. That does sound like too much prop for your engine though because that's what I've got on my CD33 which has a larger engine. You should be able to get 80-90% of the maximum rpm (as given in your engine manual) with the throttle wide open with no head wind or chop. There should be little or no black smoke in your exhaust. And your engine should not be tending to overheat. These are the symptoms of a boat that has the correct prop on board. If you've got too much prop you can drop either prop diameter or pitch and either will give your engine a better time. Dropping one inch in diameter is about the same as dropping two inches in pitch. At least this is what the local guy told me at the prop shop. I followed his advice and got pretty close to the right prop for my boat.
Ryan Turner
s/v Zenobia
Cape Dory 33, hull no. 100
Oriental, NC
rturnertec@aol.com
the general rule of thumb as I understand it is to drop two inches of pitch when you go from a two blade prop to a three blade. In your case you'd go to a 13X11 three blade prop. That does sound like too much prop for your engine though because that's what I've got on my CD33 which has a larger engine. You should be able to get 80-90% of the maximum rpm (as given in your engine manual) with the throttle wide open with no head wind or chop. There should be little or no black smoke in your exhaust. And your engine should not be tending to overheat. These are the symptoms of a boat that has the correct prop on board. If you've got too much prop you can drop either prop diameter or pitch and either will give your engine a better time. Dropping one inch in diameter is about the same as dropping two inches in pitch. At least this is what the local guy told me at the prop shop. I followed his advice and got pretty close to the right prop for my boat.
Ryan Turner
s/v Zenobia
Cape Dory 33, hull no. 100
Oriental, NC
rturnertec@aol.com
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mike
Re: PROPELLERS
We once had a C30 with a 2 blade prop. I thought and thought and read and read about going with a 3 blade. In the process, I came across something that just made good sense. That is, the amount of increased ooomph/torque/whatever was going to be neglible. The amount of increase in fuel usage was also neglible. The decrease in speed by going from 2 to 3 was negligible. The cost of hauling the boat and buying the prop was not. In summary, it made absolutely no sense to change it out. The problems in backing are due to full keel. Not a 2 blade prop.HI!
I HAVE A CD28 SAILBOAT WHICH HAS A 2 BLADE 13 X 13 SAILOR PROPELLER
ON IT AND I WOULD LIKE TO REPLACE IT WITH A 3 BLADE PROP.
WHAT SIZE HAVE OTHER OWNERS FOUND TO BE THE BEST CHOICE FOR A
THREE BLADE PROP?
michaelconniesmith@home.com