Noisey prop shaft

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Noisey prop shaft

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9 June 2012 at 14:15 #34793
wayne quigley
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@waynequigley28540
Hi Guys

I have a last installed my prop shatf ,installed support allong it.s lenth checked no bends ect .I have filled tube with copper slip and install prop shaft in tube but no prop on the end.

when the motor is run the system is so noisey. i have tried a CV joint.2 CVjoints and even a short length of hose but makes no differance.

I can say I remember the other shafts I have used being so noisey.

the motor run noise free disconected from prop.

can any one give advice please

Wayne
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9 June 2012 at 14:15 #2141
wayne quigley
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@waynequigley28540
9 June 2012 at 17:54 #34794
Paul T
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@pault84577
Hi Wayne

How long is the shaft?

Paul
9 June 2012 at 18:34 #34795
ashley needham
Participant
@ashleyneedham69188
Wayne.. I had a noisy shaft in my TBD…and so I changed it…and it was STILL noisy…so I changed the prop…and it was quiet.

Lesson…out of balance props, or props that set up some sort of resonance.

I could not believe the difference.

NOT SUGGESTING that this is your problem, but worth a try.

Ashley. ps Paul is angling for info on your shaft length because longish shafts are prone to vibrate as the actual shaft is not supported very well in the middle and so they can flex (I recon) ??

How long is long tho`?

Ashley again. and are your nuts adjusted for minimum play (end float)
9 June 2012 at 18:49 #34799
Paul T
Participant
@pault84577
Ashley ( go to the top of the class)

Wayne to explain further:

A long shaft without supporting bearings within the tube will oscillate at different frequencies depending upon motor speed, this will be exacerbated further if the shaft is out of line or if the prop is unbalanced.

Paul
10 June 2012 at 11:50 #34810
Telstar
Participant
@telstar
Wayne The previous posts are spot on. One further point, is the threaded portion of the shaft up inside the sterntube bearings? I bought a commercial propshaft and tube where the shaft was over threaded and went into the bearing this meant the shaft had a lot of sideways movement in the tube and rattled. I returned it and got my money back, then made my own. While end to end play can be adjusted, side to side play cannot.

Cheers Tom
10 June 2012 at 13:56 #34814
wayne quigley
Participant
@waynequigley28540
the prop is 12inches and the unthreaded part of the shaft isout side the tube

thanks for the info does any one if went in the water the noise will reduce
10 June 2012 at 14:36 #34815
Paul T
Participant
@pault84577
Wayne

Re check the shaft and tube for straightness, does the shaft bind or do you feel a resistance when inserting the shaft into the tube?

Paul
10 June 2012 at 18:41 #34818
ashley needham
Participant
@ashleyneedham69188
W. re last post… the boat will be noisy out of the water if this is what you are referring to.

12", if is a 4mm shaft is probably on the limit for comfort on the propshaft whipping front (at least I would hesitate before fitting such a long shaft at 4mm).

Not that you have a bit, but rolling the actual shaft on a bit of plate glass (or any bit of glass nowadays) would soon show you if the shaft was in any way not completely straight (as suggested checking by Paul).

Make sure you have adjusted the shaft end nuts for minimum play…or even make some nylon/plastic washers (out of milk containers) and adjust for NO play (not really tight, obviously).. this will help tension the shaft a touch and assist matters.

Ashley
10 June 2012 at 20:29 #34822
wayne quigley
Participant
@waynequigley28540
I will re check prop shaft and report back but I feel no resistance when inserting shaft, may be at least a lesson has been learnt about the shaft size what size is most common to be used

Wayne
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