25D aperture

[Ray Worthington]

Has anyone put a 13 inch prop on a 25D? I'm concerned that a 13 inch prop will hit the rudder. Someone is undoubtedly asing why I would want to do this. Once I finish with my present project I will post a detailed description and the results. I may be the envy of the 25D fleet.



acw@thebest.net

[Jim Westpfahl]

We purchased our 25D with a 12" three-blade prop. Cannot imagine why I would need a larger prop. However, our boat is more "even keeled" when in reverse than sister boats with the original two-blade prop. Anxious to read your reaction to the 13" modification. I'm going down to check on Belladonna today and will measure for a fit. If memory serves, a 1/2" radius difference should not pose a problem. Or will it?
Jim



JamesW7644@AOL.COM

[Lou Ostendorff]

Hi Ray;
After reading your post, I pulled out a close-up picture I made of Karma's aperture and prop; based on the inclination of the stern tube and prop position, it appears that the clearance problem would be on the bottom edge of the aperture...the overall size of the aperture looks like it could easily accomodate the larger prop...my next question would be, why do you need it? Karma easily has enough power from the 1GM10 and a 12" 3-blade...additionally, the larger prop may degrade your sailing characteristics somewhat...anyway, I hope your project turns out OK and gives you what you're looking for. Good Luck!
Lou Ostendorff
CD25D "Karma"
'82, #63



louosten@ipass.net

[Larry DeMers]

The 13in. prop would violate the clearance at the tips needed for the prop to work properly. They need about an inch and a half clearance..there is a formula out there for it for exact calculations..but the 13 will not work on my CD30, so I doubt it will work on your 25D. Call the vendor and tell them what you have to work with..engine hp, shaft diam and height of the aperture, as well as distance from deadwood to rudder at three points..amidships, and hard over P/S. Try a 12 in. 3 blade..it's the only alternative I think.

Larry DeMers
s/v DeLaMer
Cape Dory 30

Has anyone put a 13 inch prop on a 25D? I'm concerned that a 13 inch prop will hit the rudder. Someone is undoubtedly asing why I would want to do this. Once I finish with my present project I will post a detailed description and the results. I may be the envy of the 25D fleet.

demes@sgi.com

[Ray]

Lou: I have tried three times to reply to your post and email and each time it has come back "undeliverable". While my answer is a bit premature, I'm repowering my 25D with a Yanmar 2GM. The most likely modification will be lengthening the engine beds a couple of inches. Otherwise, the 2GM will fit. It's the same transmission as the 1GM and the wiring harness plugs right in. The prop that came with the engine is a Michigan Wheel 3 blade Sailer 13 X 12. My concern is that the additional inch in diameter will cause the prop to hit the rudder when the tiller is pushed hard to port or starboard; hence, my question in the post. As I said, once the engine is installed and I'm underway again, I will post the results of having a 2GM (13 horsepower engine) in a 25D.: Has anyone put a 13 inch prop on a 25D? I'm concerned that a 13 inch prop will hit the rudder. Someone is undoubtedly asing why I would want to do this. Once I finish with my present project I will post a detailed description and the results. I may be the envy of the 25D fleet.



acw@thebest.net