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![]() "C. S." wrote in message ... As somebody else pointed out the answer to the "no vibation" may be counter balance. There is about one meter of free shaft between the bottom of the boat and the support in front of the prop. Maybe the shaft flexes enough to counterbalance the missing blade? But why is there no power in reverse? C.S. I can't think that's the answer. If the shaft flexes from centrifugal force (and I would hope it wouldn't flex much anyway), it would be pulled toward the single blade rather the opposite direction which would be necessary to counterbalance. That's what probably happens with my saildrive, which can move on the rubber motor mounts, accentuating the shaking. I would expect your shaft to be more rigidly secured than my saildrive, and may not allow this. I can't explain the difference in thrust. Under sail, if your engine is in neutral, does the prop open up and spin ? |
#2
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posted to rec.boats.cruising
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![]() "Garland Gray II" wrote in message ... "C. S." wrote in message ... As somebody else pointed out the answer to the "no vibation" may be counter balance. There is about one meter of free shaft between the bottom of the boat and the support in front of the prop. Maybe the shaft flexes enough to counterbalance the missing blade? But why is there no power in reverse? C.S. I can't think that's the answer. If the shaft flexes from centrifugal force (and I would hope it wouldn't flex much anyway), it would be pulled toward the single blade rather the opposite direction which would be necessary to counterbalance. Now I don't follow. I think the trust from the single blade would push the shaft to the opposite side and thus generate a counterbalance effect. That's what probably happens with my saildrive, which can move on the rubber motor mounts, accentuating the shaking. I would expect your shaft to be more rigidly secured than my saildrive, and may not allow this. I can't explain the difference in thrust. Under sail, if your engine is in neutral, does the prop open up and spin ? It does spin but not very fast so I don't know if it is open or closed or somewhere inbetween. C.S. |
#3
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posted to rec.boats.cruising
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"C. S." wrote in message ... "Garland Gray II" wrote in message ... "C. S." wrote in message ... As somebody else pointed out the answer to the "no vibation" may be counter balance. There is about one meter of free shaft between the bottom of the boat and the support in front of the prop. Maybe the shaft flexes enough to counterbalance the missing blade? But why is there no power in reverse? C.S. I can't think that's the answer. If the shaft flexes from centrifugal force (and I would hope it wouldn't flex much anyway), it would be pulled toward the single blade rather the opposite direction which would be necessary to counterbalance. Now I don't follow. I think the trust from the single blade would push the shaft to the opposite side and thus generate a counterbalance effect. Actually, I was just considering the centrifugal force involved. Not sure which way lopsided thrust would go. That's what probably happens with my saildrive, which can move on the rubber motor mounts, accentuating the shaking. I would expect your shaft to be more rigidly secured than my saildrive, and may not allow this. I can't explain the difference in thrust. Under sail, if your engine is in neutral, does the prop open up and spin ? It does spin but not very fast so I don't know if it is open or closed or somewhere inbetween. What I was wondering here was whether your prop has a tendency to stay folded unless "forward" rotation literally forces it open.. Under sail, my prop immediately pops open and spins should the transmission accidently be shifted to neutral. This doesn't necessarily explain why your prop worked in reverse with both blades, but not with one, unless the remaining blade was stiff with fouling and didn't have the other blade (geared together on mine) to force it out. I don't know. Very strange. C.S. |
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