Yankee 30 Message Board

Posted by Carl Seipel on 12/24/2003, 2:44 pm
66.81.217.105

Hi Yankee sailors: I purchased hull 62 with a sick Atomic in May 2002. A couple of days ago,after struggles that nearly broke the back of my enthusiasm, I got the boat back in the water with a little 10hp Kubota marinized diesel in place. My installation is a copy of Bill Ramelli's on Andiamo, using a CV flexible joint and a glassed in thrust bearing plate. This has allowed me to mount the engine skewed to the prop shaft and fitting nicely in the existing space under the settee without any modifications, except the engine bed, in that area. My small diesel runs at 3600rpm max and has a 2.72:1 gear ratio in forward and 2.1:1 ratio in reverse. I am using a borrowed 12x12 three-bladed prop as a trial horse, which I have allowed to stick out 3 inches behind the cutlass bearing in the keel in order to achieve some kind of clearance between the blades and the hull above. Even so this clearance is only about one inch which is certainly less than the stated minimum of 15% of prop diameter all propeller instructions mention. I have taken a couple of test trips and I am not happy with the propulsion. In forward the engine is able to reach max revs but the prop does not seem to have any real bite and starts singing (cavitating?) when I crank up hard. In reverse, with clearer water to grip and a smaller gear ratio the engine smokes and is not able to rev up. Obviously I must do something to pitch and diameter to improve the situation. I realize that a lot would be gained by extending the shaft and using a strut but I hate to have to go through with that also if there is any way to get decent performance without doing so. Undoubtedly the Yankee 30 was not designed to be a great power cruiser. There is a problem with the prop so close to the keel and such limited space to swing with respect to the bottom of the hull just above the prop. However, I am hoping to do a bit of traveling in this boat and I would hate not to have reasonable performance under power also. I am now calling all good Yankee owners to my assistance with advice. I would love to know what props you are running on your boats at what shaft rpms and what performance you are getting. Any and all opinions and information much appreciated. In the meantime Happy Holidays... Carl Seipel