Port Side Thumping?

[GregorLuv]

Hi Everyone!

Been a while since I came back here. I have a beneteau first 305 and after spending another 10k on parts and labor seems like I have a whole brand spanking new issue:

When I steer at 5 KM (it only goes to 7) on my 2002 Volvo-penta engine and I steer port side (its a port side only issue) the boat vibrates and I hear a fluttering sound.

I thought it was because the rudder was misaligned because I had to have someone redo the rudder stopper but the guy tells me its not the rudder.

So he is either b.s.ing me and claiming its a fuel filter or its really not the rudder.

What do you guys think? Obviously the worse thing to happen is me getting stranded RUDDERLESS in the bearing sea.

 

[SG]

Gregor -- By the way, your "profile" still lists a MacGr[e]gor 26m in Alaska...

Back to the issue at hand:

When I steer at 5 KM (it only goes to 7) on my 2002 Volvo-penta engine and I steer port side (its a port side only issue) the boat vibrates and I hear a fluttering sound.​

• Does your Beneteau First 305 have two rudders?
• 
  
  
• Do you mean when you turn the boat a little to port or what?
• Do you mean that when you turn the rudder to go to Port you notice a vibration that that you don't notice when you turn the rudder to Starboard?
• Do you notice this same symptom when you are sailing at the same speed and performing the same maneuver?
• Do you notice this at variable degrees of rudder angles when turning to port? i.e., if you turn the rudder 5 degrees vs. 25 degrees vs. hard to port -- until it reach the rudder stop?
• Do you notice this if you're going at 3 knots? Or only at 5 knots?
• Do you notice it if you motor flat-out?
• Do you have a wheel or a conventional tiller?
• Do you feel the rudder pulsating?
• Has someone looked at the rudder quadrant (if you have a wheel) or the rudder post to see if you have noticeable play or vibration while this is happening?

 

[Ron20324]

Do you have a folding prop that needs to be assisted to close by shutting the engine off and putting the shift in reverse to fold the blades and then all is quiet?

 

[Gunni]

Make sure your rudder cables, chains, sprockets and wheel axle are all in good shape (no loose play). If not those items then go over the side and check your rudder for play in the rudder stock.

 

[GregorLuv]

The boat has a single rudder (center). https://postimg.org/image/53i4m7rg9/

Rsz_10617171444_hdr

• GregorLuv
• Jun 30, 2017

When I turn the boat to go port side the vibration starts and the steering feels a bit unstable (like I couldn't balance going straight in the direction I intended the boat to go).

Subsequently if I turn the boat starboard there is no such vibration (I could go in circles steering starboard without this issue).

The rudder stop was custom retrofitted and I was told that the steering quadrant looks good. When the boat was hauled out I felt no play in the rudder. https://postimg.org/image/6k6jtb7tj/

6111

• GregorLuv
• Jun 30, 2017

Non-folding Prop: https://postimg.org/image/l0iywz0qp/
https://postimg.org/image/ffll55s9r/

Rsz_0617171340

• GregorLuv
• Jun 30, 2017

Wheeled steering and the steering has no detectable play.

So in terms of knots I noticed it a heck of a lot more at 7 knots than I did at 5 and nearly no issue at around 3 but obviously I was trying to get back into the port fast thinking I might be losing a rudder.

 

[SG]

You have wheel or a tiller?

Wheel, my guess is the quadrant or rudder post or steering cables.

Tiller, rudder post would be my guess

 

[GregorLuv]

You have wheel or a tiller?

Wheel, my guess is the quadrant or rudder post or steering cables.

Tiller, rudder post would be my guess

Sorry I have a wheel.

 

[SG]

The fuel filter doesn't relate in any way.
If it doesn't happen when you are sailing, but happens only when you motoring, then MAYBE it's a disconnected motor mount.

Do you feel the flutter in the steering? Or, is it a general thumping?

Have someone steer the boat, look at the engine, shaft, steering quadrant, and rudder tube.

If it doesn't happen when you are sailing (or maybe being towed), then it's something related to the engine, it's mounts, maybe the linkage, etc.

That's my gut reaction, Gregor.

 

[cymeyer]

I agree with SG that this could be an engine issue. I would check the engine mounts and also the engine alignment with the prop shaft.

 

[JamesG161]

Try the same rudder position that you get the thumping but in...

Reverse

If nothing, go opposite rudder in Reverse. This should eliminate the rudder if NOTHING observed.
Reverse will put stress on the motor mounts but in opposite direction.
________

MAYBE it's a disconnected motor mount.

A motor mount may be cracked and hidden. One bad motor mount can cause a bad shaft alignment when under high thrust.
Jim...