Rudder problem

[caughtthewind]

Hi guys

Just hauled out my to be Beneteau 411 for inspection/survey and noticed that the rudder is hitting the hull when turned fully to the starboard.

What do you reckon the problem is please?

[Cavalier]

Originally Posted by caughtthewind

Hi guys



Just hauled out my to be Beneteau 411 for inspection/survey and noticed that the rudder is hitting the hull when turned fully to the starboard.



What do you reckon the problem is please?

Is the upper corner of the leading edge or trailing edge hitting the hull? If leading edge then your rudder is bent towards starboard, if trailing edge then bent towards port.

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[caughtthewind]

It's the upper corner of the trailing edge that is hitting the hull, but only when turned to starboard. The rest have good clearance.

[Cavalier]

Originally Posted by caughtthewind

It's the upper corner of the trailing edge that is hitting the hull, but only when turned to starboard. The rest have good clearance.

It's worth checking to see if the rudder bearing and bearing-shoe has been displaced. Also check to see if there is too much movement in the rudder (I.e. Can you shake/rattle it) forward to aft? Otherwise it would suggest that the rudder stock has been bent to port and slightly aft (collision?).



Is the trailing edge corner hit stopping the rudder going to it's full end-stop (the restrainer chains at the quadrant) or simply brushing/wearing on the bottom paid.

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[caughtthewind]

Bearing seem solid. Cannot notice any play. I'll be inspecting this tomorrow in more detail. Antifouling is gone where it is brushing.

[Cavalier]

Originally Posted by caughtthewind

Bearing seem solid. Cannot notice any play. I'll be inspecting this tomorrow in more detail. Antifouling is gone where it is brushing.

Might also be worth checking inside the hull at the rudder tube to see if there's any cracking around the joint between the tube and the hull or between tube/hull and gusset plates (supporting triangular plates that reinforce the angle between rudder tube and hull).

Good luck!

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[Cavalier]

Originally Posted by caughtthewind

Bearing seem solid. Cannot notice any play. I'll be inspecting this tomorrow in more detail. Antifouling is gone where it is brushing.

Also, get a length of inextensible string/line and put a loop in one end and put it over the winch on the stb side, then pull the string taught down to the middle of the base of the rudder, marking off the position on the string. If you do the same with the line from the port winch (assuming them both to be symmetrically located around centerline), then you'll get an indication of how far to port the rudder is bent.

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[caughtthewind]

Hi guys

Here are a couple of photos. When the rudder is turned to starboard you can see that it brushes against the hull while to port you can see the proper clearance.

[rognvald]

I believe Cavalier is correct. Check rudder shaft and rudder tube inside the boat. It's a simple matter of physics. Good luck and safe sailing.

[gamayun]

Originally Posted by rognvald

I believe Cavalier is correct. Check rudder shaft and rudder tube inside the boat. It's a simple matter of physics. Good luck and safe sailing.

I'll be curious how this turns out. I had dropped my rudder last year and everything was straight but I noticed a piece of wood had been taped to the rudder stop by the PO. I removed this and am now noticing that the rudder is rubbing away the paint on the port side. There is good clearance on the starboard side. Everything otherwise looks good at the rudder post so I'm going to reinstall the wood stopper! At least until I figure out if this is a problem....

[rognvald]

Originally Posted by gamayun

I'll be curious how this turns out. I had dropped my rudder last year and everything was straight but I noticed a piece of wood had been taped to the rudder stop by the PO. I removed this and am now noticing that the rudder is rubbing away the paint on the port side. There is good clearance on the starboard side. Everything otherwise looks good at the rudder post so I'm going to reinstall the wood stopper! At least until I figure out if this is a problem....

There is one thing both you and the OP should also consider: misplacement of a retaining shaft collar when the boat was manufactured or after a later repair. Although the shaft is generally held in place by the steering quadrant with a shaft bolt, there could very well be some slippage if a shaft collar is either out of alignment or one does not exist. When I pulled my rudder for rebuild, I replaced my shaft collar directly above the shaft tube and added an additional collar directly below my upper bearing for added security. Perhaps overkill, but bulletproof. However, as Cavalier noted earlier, I would have a strong suspicion of a slightly bent shaft since even a defective rudder bearing would cause improper alignment/rubbing on both port and starboard. Take a trip to the back of your boat and look at your steering system carefully. Take some pix so you can think about it over time. I hope this helps. Good luck and safe sailing.

[caughtthewind]

Hi guys,

I ended up dropping the rudder. All seems well with the rudder. The rubbing is quite minimal but I did not want to splash it back without doing something about it.

I sanded the top of the rudder and of course, I have now taken off the gel coat layer and exposed the core of the rudder. How should I protect the core now? Apply gel coat? Fibreglass? Primer?

Any help is appreciated.

Thanks for all your above comments.

[Cavalier]

There's, of course, a number of ways tp attack this...

Now you've exposed the core, you'll need to reseal it in with epoxy (always underwater so don't use polyester) and fair down the area to the correct profile. Once that's complete you may want to sand around the area of the repair and reseal with a decent barrier coat or four (Interlux 2000e or similar), such that you ensure a continuous surface. Finish off with reapplying your anti foul.



You'd be smart to start off ensuring that you have enough clearance on the modified area to re-add epoxy, barrier and anti-foul, so that you don't end up back at square one w.r.t. a lack of clearance.

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[UNCIVILIZED]

It's an obvious possibility, or perhaps not so much, but the rudder itself may not be mounted 100% vertically in the boat. Which actually is quite common (ditto the keel).

Get several good plumb lines, & hang then in front of & behind the keel. Then adjust the boat so that the keel is plumb (carefully) using the screws on the jack stands. And then have a peek at the rudder & see if it's lined up with the keel/is plumb. Not that keels are always 100% straight either, nor are masts. But you can check the keel (or the spar) similarly, as well as by using a tape measure led to the gunwales on either side of the boat.

Also, it's quite common for boats to not have 100% symmetrical hulls. There are a lot of things that can contribute to this. Anything from the mold halves being slightly different from each other, to the boat bending slightly as they were being joined, or while she was being built. Including a few of her bulkheads being a tiny bit asymmetrical. Or even that when the hull halves were joined, one side of the joint got a bit more laminate or fairing compound than did the other.

Getting something as big as a boat, with as many complex curves as they have, to be totally symmetrical is tough. Even nowadays, with all of our high tech measuring & machining tools. Let alone 20 or 40yrs ago. When boats were literally drawn full size by hand.

Long winded theories not withstanding, pull the rudder & check the shaft. Since if it's bent you'll want to know. And bends can be a focal part for the beginnings of crevice corrosion or cracking. Plus it'll give you a good chance to do a good inspection of ALL of your steering gear.

PS: Boat hulls also change shape over time. Due to extended periods on the hard, asymmetrical loadings on their structures, load imbalances in tankage or ballast flexing the hull, holes (doors) in only the port or starboard side of a bulkhead, imbalanced laminates in the hull's structure between port & starboard, sailing more on one tack than the other for years on end due to localized wind patterns, out of plumb out of tune rigs stressing the hull, broaches/knockdowns bending her structures a tiny or not so tiny amount. The list is endless.

[psk125]

Unciv seems to hit the nail on the head: lots of possible reasons for this. Your solution of shaving off the offending part of the rudder seems like the most practical and simplest one. If you haul again next year and it happens again, THEN you should try harder to find out exactly what is going on and fix it.