Rudder noise when motoring with wheel centered

[LifesBetterWhenYoureBeating]

Hi folks,

The rudder on my '90 Passport 41 recently started making some noise when I'm motoring at more than 1200rpm and the wheel is centered. As soon as the wheel is moved or the revs lowered, it stops. It doesn't happen when sailing.*

It makes a series of knock sounds like if the rudder is moving a little bit from side to side, which is not surprising as there's a little bit of play on my rudder. It seems clear to me it's the turbulence generated by the prop that is causing it, but I'm wondering why it only started now given that the play on the rudder was noticed when I bought the boat. Has anybody experienced this? Any tips on how to troubleshoot further of fix it?

Thanks in advance!*

[Don C L]

I have not sailed a Passport 41 (sure like to though) nor have I experienced this, but my first thought is are you sure it's the rudder? If so, could it just be vibrating in resonance with the engine vibration? (Does the engine vibrate more at that RPM?) The turbulence idea makes sense too of course, so maybe the bearings need to be checked. I don't know but do you have good access to the rudder post from inside so you can move it around to see where it is loose?

BTW you said you have a '90? Could it be an '89 instead (since what I see says they were built until '89?) Or maybe you have the 40?

[neilpride]

You can check the tension on the quadrant cables if the rudder has one, you can also try to brake the wheel a little if the pedestal has a brake.
Also the play in the rudder could be worse since you bought the boat.

[Cheechako]

Originally Posted by Don C L

I have not sailed a Passport 41 (sure like to though) nor have I experienced this, but my first thought is are you sure it's the rudder? If so, could it just be vibrating in resonance with the engine vibration? (Does the engine vibrate more at that RPM?) The turbulence idea makes sense too of course, so maybe the bearings need to be checked. I don't know but do you have good access to the rudder post from inside so you can move it around to see where it is loose?

BTW you said you have a '90? Could it be an '89 instead (since what I see says they were built until '89?) Or maybe you have the 40?

The 41 was built after the 40. In a different plant also.

[Cheechako]

Originally Posted by LifesBetterWhenYoureBeating

Hi folks,

The rudder on my '90 Passport 41 recently started making some noise when I'm motoring at more than 1200rpm and the wheel is centered. As soon as the wheel is moved or the revs lowered, it stops. It doesn't happen when sailing.*

It makes a series of knock sounds like if the rudder is moving a little bit from side to side, which is not surprising as there's a little bit of play on my rudder. It seems clear to me it's the turbulence generated by the prop that is causing it, but I'm wondering why it only started now given that the play on the rudder was noticed when I bought the boat. Has anybody experienced this? Any tips on how to troubleshoot further of fix it?

Thanks in advance!*

If it truly is the rudder, I would say you have some wear on the gudgeon on the skeg bottom maybe? The prop thrust is wobbling it slightly while it is in a neutral lightly loaded situation.

[LifesBetterWhenYoureBeating]

Originally Posted by Don C L

I have not sailed a Passport 41 (sure like to though) nor have I experienced this, but my first thought is are you sure it's the rudder? If so, could it just be vibrating in resonance with the engine vibration? (Does the engine vibrate more at that RPM?) The turbulence idea makes sense too of course, so maybe the bearings need to be checked. I don't know but do you have good access to the rudder post from inside so you can move it around to see where it is loose?

BTW you said you have a '90? Could it be an '89 instead (since what I see says they were built until '89?) Or maybe you have the 40?

I don't think it's resonance with the engine vibration because as soon as I move the wheel the noise stops.

I had a look at the rudder post and steering radial when it was vibrating and I could feel it when touching but there was nothing visibly moving

I'm pretty sure mine was built in '90. AFAIK Most of the 41s were semi custom builds and indeed from a different plant as someone mentioned in this thread

[stormalong]

Check everything. Engine mounts (are they original?), cutlass bearing and rudder bearings. This could just be an accumulation of wear on cutlass bearing and rudder bearing. The reason I suggest that you check the engine mounts is that one could be broken. After 33 years they should be replaced anyway.

[Don C L]

I am guessing you are feeling it in the wheel though, right? You are feeling the wheel wobble like a car with a wheel out of balance?

[donradcliffe]

If you were on the west coast I would check for kelp on the rudder.

[LifesBetterWhenYoureBeating]

Originally Posted by Don C L

I am guessing you are feeling it in the wheel though, right? You are feeling the wheel wobble like a car with a wheel out of balance?

Nope, I don't feel anything on the wheel

[neilpride]

Well, if you don't experience nothing at the wheel , guess you need to replace rudder bearings.

Same thing happen to me in my old CSY ,i found out that it was a lot of pitch in my max prop.

[TrentePieds]

Judging by the arrangement drawing given in SailboatData, the thrust line of the prop shaft is aimed just precisely at the bottom of the skeg/rudder on this boat.

The roiling of the prop wash must necessarily vary with the RPM and it therefore makes sense to me that at some given RPM the flow lines of water within the propwash would set the rudder to shaking in harmony. With a perfectly sound bottom bearing at the bottom of the rudder, the vibrations would be absorbed by the skeg, but with a worn bearing the rudder stock would "hammer" from side to side within the bearing.

If that surmise is correct, you would not feel the vibration when sailing because it simply wouldn't be there. At RPM other than the critical one, the roiling of the propwash would be of a different character and no harmonic would be set up.

This boat is obviously wheel-steered, so as someone else has said: Do check the integrity and correct adjustment of the linkage twixt the wheel and the quadrant/tiller at the top of the rudderstock. On the next haul-out have a look at the bottom bearing in the skeg and replace it it there is any play.

TrentePieds

[c.K.]

Originally Posted by Don C L

I have not sailed a Passport 41 (sure like to though) nor have I experienced this, but my first thought is are you sure it's the rudder? If so, could it just be vibrating in resonance with the engine vibration? (Does the engine vibrate more at that RPM?) The turbulence idea makes sense too of course, so maybe the bearings need to be checked. I don't know but do you have good access to the rudder post from inside so you can move it around to see where it is loose?

BTW you said you have a '90? Could it be an '89 instead (since what I see says they were built until '89?) Or maybe you have the 40?

When you motor in a straight line the forces are even on both sides of the rudder blade causing vibration due to prop turbulence and play in the rudder shaft or at the hinge points, when turning the forces are uneven so less noise no prop turbulence when sailing so less noise

[Celestialsailor]

I would also say rudder bearing. As soon as you turn the wheel slightly and it goes away is because you are now side loading and the shaft is biased by water force to a side load.

[Sos]

I fitted new 3 bladed feathering props which have higher thrust than my original fixed 2 bladed props. I got the same sort of vibrations.
Had the boat out this winter and dropped the rudders and yes the rudder bearings were worn. Looks like that is your problem.