Rudder repaired - issues now

[Macintechno]

Hi all,

Got a quick question just in case someone has an idea.

We pulled the boat out a few weeks ago and there was water coming out of the rudder. All bolts had corroded and could be pulled out by hand. There was a hole in the bottom of the rudder where water got in.

Shipwright said it needs to be fixed. They apparently opened the rudder which was hollow, reinforced it with glass, filled it with foam panels and glasses it over.

Boat back in the water and it just doesn’t go the way it did before…. If I let the tiller go at 5kn the boat goes hard to port (not fully but at least 20-25degrees) and keeps doing circles.

If I hold the tiller straight there’s a lot of pressure (tiller wants to go towards starboard) and when I sit at the port cockpit seat I need to hold it quite strong to keep it straight. If the tiller is dead straight and I hold it like that the boat goes to starboard. I need to put the tiller to port by 5-7degrees to go straight.


Even at the mooring with no water going across the rudder the tiller turns to starboard until the tiller hits the seat.

I feel there’s flotation in the rudder and since the lower edge of the rudder is larger than the top edge it will move up to one side.

Does anyone have any thoughts on it? The shipwright thinks it may not be shaped correctly but that does not explain to me the force that is on it when in the water.

He will need to pull the boat out again but I’d like to have an understanding of what it could be.

Kind regards
Daniel (Stellar, MKIII)

[steve]

Hi Daniel,

Foam inside the rudder is the standard arrangement for a Mark 3. Most of the weight of the rudder is in the stainless steel shaft so the back part of the rudder is probably lighter than water and may be inclined to float upwards. This would explain why the tiller moves to one side when you are moored. It is not something I have observed on my boat, but appears theoretically possible. It is good practice to tie the tiller amidships when anchored even if there is no current or waves.

Were you motoring or sailing when the boat was misbehaving? You mentioned that the boat was doing circles which would suggest you were motoring. If you have an outboard, was it centred? If you have an inboard with the propeller between hull and rudder, then maybe there is some slight asymmetry on the face of the rudder immediately behind the propeller, which might not be a problem when sailing. It is hard to imagine that a rudder would be so misshapen as to cause a serious problem when sailing without being clearly visible before launching.

Regards
Steve

[Macintechno]

Hi Steve,
I was in the boat today again to check some things. The tiller is very happy to move to the starboard side of the boat so it indicates the rudder floats rather toward the port side. When amidships I can give it a little nudge to port and then it will slowly turn the tiller to port but not as much as the other way.

The tiller is always tied amidships when I’m not on the boat but I had just noticed it Just when income back to the cockpit after picking up the buoy and then I did some more playing with it to confirm the behaviour.

When I came home from the hard I was motoring with outboard centred. But to test it I did switch the outboard to neutral at 6kn before letting go of the tiller which results in identical behaviour (turning hard to port)
I Just never had that before. I could happily Motor with outboard on full steam ahead and wouldn’t have to hold the tiller. She’d just go straight. Now as soon as I let go it turns to port.

I believe it’s a combination of mis-shaped rudder (causing lift on the port side) and it floating up.

I will try calling the shipwright again and get him to pull her out again. Open the bottom stern facing corner and add some lead before closing it up and reshaping it properly.

Kindest
Daniel

[steve]

Hi Daniel,

Is it possible that the outboard is not sitting properly on its bracket, so the shaft is not vertical and the propeller is therefore off centre?

regards
Steve

[Phillip]

Shaun and I have discussed this and we cannot see much of a problem.
Remember Top Hats will look after you, in other words if you get into trouble when sailing, letting go of the tiller will cause her to round up and heave too.
To say she will do donuts when you let go of the rudder under power is probably a good thing in that she just doesn't sail off over the horizon!
All yachts have their own little unique problems and one of the joys of sailing is to overcome them.

[Miker]

Maybe Bear, Phil or Shaun can clarify this, but on my Mk3, I also have a hollow rudder that has a drain hole at the bottom. The guys who've slipped my boat for the last 14 years have never said there was anything wrong with it, although have picked up, and repaired all kinds of other small issues when doing the annual slip.

If they filled your rudder with foam, it will indeed float and do what you've said, as in turning one way or the other.

Mine has given no issues and steers true when left free, so yours may have been perfectly fine left well alone.

There is a thread here that discusses the internals of the rudder in some detail. viewtopic.php?f=6&t=2203&hilit=rudder

[steve]

Hi Daniel,

The design drawing for the rudder indicates that it should be foam filled. When I cut mine open there was no foam but there was a brown sludge coating the inside. The sludge may have been the disintegrated foam or mud from the muddy creek that my boat is moored in. I did not bother replacing the foam but ideally it should be there to prevent water reaching the polyester resin.

Inserting lead into the rudder as you propose seems unnecessary as other boats do not have it. Is it of any consequence if the rudder moves to one side while moored? The weight of the tiller will theoretically cause this even if the back of the rudder is not buoyant.

As the problem appears to be while motoring you could check (a) that the outboard is in the centre of the well. (b) that the outboard is sitting flat on its support so its shaft is vertical, and (c) that the outboard is pointing straight forward. Presumably while motoring the problem can be solved by pointing the outboard to one side, even if the cause of the problem is the rudder.

Have you tried sailing, with the outboard lifted out of the water, on both tacks? Only if there is a great disparity of the required tiller position on each tack, would the rudder appear to be the cause of your problem.

Regards
Steve

[Macintechno]

Hi all,

Thanks for your feedback.

My major concern is that this has never happened before. When I motored around I always went straight without holding the tiller. Now I can’t do that. Even at low speed with the engine off I need to hold onto the tiller. There is no difference when the motor is engaged or not engaged. Haven’t sailed her yet but will try soon. Motor setup is fine. Straight as always. No change to prop or bracket (sitting in a well)

It’s just such a massive difference to how it was before. It wouldn’t worry me what the tiller goes on the mooring but if I have to hold onto the tiller all the time it’s weird. I could sail my boat without holding the tiller on a straight line by balancing the sails. I doubt that I can do that now. When I let go of the tiller it feels like a crash tack quick stop method. I’ll try it under sail - will be fun…

The shipwright says it’s likely that they didn’t shape it properly. I think that may be true but the floating suspicion may have more weight on that?! Not sure yet…

To me it is a problem as it was never like that.

Kindest,
Daniel

[steve]

Hi Daniel,

Did you manage to sort out your rudder problem? I am curious to know what the remedy was.

Regards
Steve

[Macintechno]

Hi Steve,

I got the boat back last week after it was pulled out of the water again. The rudder still floats up when on a mooring likely due to the foam inside. But that’s not at issue at all.
The sharp turning is no longer the case. The blade was mis-shaped and caused it to turn as suspected by some users and the shipwright.

After reshaping the blade we’re good.

Cheers
Daniel