CDI special reversing prop

[John]

Has anyone ever tried using one of the CDI props that are specifically designed to supposedly greatly improve reversing performance? It's an odd looking prop as the trailing edge of each blade is cut off as a straight edge, not radiused as on a typical prop. I would sure like to know if it would help with the classic reverse steering problems of CD's..........does anyone know if it would help? If yes, then to what degree?

[Tom]

Has anyone ever tried using one of the CDI props that are specifically designed to supposedly greatly improve reversing performance? It's an odd looking prop as the trailing edge of each blade is cut off as a straight edge, not radiused as on a typical prop. I would sure like to know if it would help with the classic reverse steering problems of CD's..........does anyone know if it would help? If yes, then to what degree?

If you are talking about the one that was designed by a computer and is made from strong plastic and 90% more efficient in reverse than a standard prop then I tried it a few years ago. Didn't like it. It REALLY walks sideways in reverse. It may be more efficent in that it gives you more pull in reverse, but it makes the steering even worse. They also have a funny little vibration in forward which I think is the blades flexing. I was afraid that it was wearing my cutlass bearing and didn't notice any particular improvement in forward thrust and harder to steer in reverse, so at the next haulout I changed to a three blade bronze which is the one I like best after trying 4 different props. I still have the plastic one -- is it marlin or martek or something like that -- which I keep for a spare but would be happy to sell for half price if you have a 1" shaft. The trick to steering a full keel in reverse is to just get the boat moving, then shift into neutral so the prop doesn't walk your stern while you are steering. It isn't perfect, but I have never seen it as a big problem. Fin keelers are just spoiled. How often do you motor in reverse except for getting out of the slip and putting on the brakes? In my case virtually never.



TacCambria@thegrid.net

[Tom Foley]

Mariner Has a device that you attach to your present prop that closes the through-prop exhaust. It costs about $12. I havent tried it butmy mariner dealer says it works. At that price I intend to try it. : : Has anyone ever tried using one of the CDI props that are specifically designed to supposedly greatly improve reversing performance? It's an odd looking prop as the trailing edge of each blade is cut off as a straight edge, not radiused as on a typical prop. I would sure like to know if it would help with the classic reverse steering problems of CD's..........does anyone know if it would help? If yes, then to what degree?

If you are talking about the one that was designed by a computer and is made from strong plastic and 90% more efficient in reverse than a standard prop then I tried it a few years ago. Didn't like it. It REALLY walks sideways in reverse. It may be more efficent in that it gives you more pull in reverse, but it makes the steering even worse. They also have a funny little vibration in forward which I think is the blades flexing. I was afraid that it was wearing my cutlass bearing and didn't notice any particular improvement in forward thrust and harder to steer in reverse, so at the next haulout I changed to a three blade bronze which is the one I like best after trying 4 different props. I still have the plastic one -- is it marlin or martek or something like that -- which I keep for a spare but would be happy to sell for half price if you have a 1" shaft. The trick to steering a full keel in reverse is to just get the boat moving, then shift into neutral so the prop doesn't walk your stern while you are steering. It isn't perfect, but I have never seen it as a big problem. Fin keelers are just spoiled. How often do you motor in reverse except for getting out of the slip and putting on the brakes? In my case virtually never.

alewifehouse@mainecoast.net