Author Topic: Contest Rudder Problems  (Read 2095 times)

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moonie5961

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Contest Rudder Problems
« on: 29 June, 2013, 06:49:16 »
Hello, I found a significant crack in the leading edge of my rudder in my 1974 Contest 31. I have tried my best with Google translate, but could not find an answer; do Contests have any history or pattern of rudder failure?

I am considering cutting a roughly 6"x12" hole in one side of the rudder to inspect the stainless webbing/fingers that form the rudder structure. Has anyone else performed this repair, seen or heard of it being done?

Does anybody know what the rudder structure looks like inside? Depth from the surface, etc.?

Here is a link to what I am considering: http://www.epoxyworks.com/12/rudder.html

I am very interested in hearing whether these rudders are prone to failure; I cannot decide whether to risk cutting into my rudder or just clean and seal up the crack and let it be.

Thanks for any advice!


Offline Ewout

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Re: Contest Rudder Problems
« Reply #1 on: 29 June, 2013, 12:23:48 »
Hi there,

Several years ago i refitted my c34.
We saw a crack in the rudder as well.

Conyplex was asked what to do:
Their answer: the rudder is not filled with foam or anything else. It is fully filled with a massive compound that cannot take any water itself.
Just repair the crack and you will be fine..

Just my 2 cents.

Kind regards
Ewout

moonie5961

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Re: Contest Rudder Problems
« Reply #2 on: 29 June, 2013, 17:55:24 »
That makes me feel better, thank you!

I am still concerned about the possibility of crevice corrosion within the internal rudder structure, though. I noticed some pitting on the rudder shaft after grinding out a collar around the shaft where it terminates at the top of the rudder. Corrosion in this solid, substantial stock of stainless makes me wonder about corrosion at less robust pieces and welds within the rudder.

Does anybody know what the structure looks like inside?

Valentine

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Re: Contest Rudder Problems
« Reply #3 on: 01 July, 2013, 11:21:10 »
Hi,

did you follow the crack into the rudder grinding it open? So did I on the rudder of our 1967 C29. After some 1,5 cm there was only fresh and clean laminate left. So the crack didn´t go any deep and the water came nowhere near any metal parts. So corrosion is not an issue, as far as I am concerned. After that, I left it dry up for two weeks and filled it with fibre-filled Epoxy. At the end two fibre matts laminated on top, and ready. And it works just fine for six years now.

Best regards

Alex

moonie5961

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Re: Contest Rudder Problems
« Reply #4 on: 02 July, 2013, 14:43:15 »
That is very good to hear, thank you! I have ground the crack out a bit but need to go further...

Offline sjoerd

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Re: Contest Rudder Problems
« Reply #5 on: 05 July, 2013, 14:50:36 »
On our pre-purchase inspection we found some cracks in the rudder of our '84 36S. The rudder was completely solid and 100% dry. The cracks were gorund out and repeired. It was suggested to us by the surveyor that the original filling of the rudder might have caused some expansion and thus created small cracks in the gelcoat surface which then progressively opened up, so no structural failure of the rudder itself just the gelcoat.

Kindest,

Sjoerd
SY Camelot
Contest 36S
Hull# 206
Fractional rig
http://www.sailingcamelot.nl

moonie5961

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Re: Contest Rudder Problems
« Reply #6 on: 09 July, 2013, 19:04:46 »
In case anybody else is interested in the future, I emailed Dick Zaal and asked him about the construction of Contest rudders at the time.

He was very kind and replied with the detailed message below and a drawing that is representative of Contests built around 1974. Very nice man, I was happily surprised to get a response and feel much better about the situation now. I am not planning on cutting the skin away to inspect the inside, as I feel confident that the rudder is unlikely to be delaminated inside. Thanks everyone for your input, and thank you Mr. Zaal!

Message from Dick Zaal:

Although I don’t have any drawings of your Contest 31, there is not much difference in the rudder structure with the rudders of the other Contest’s.

So I enclosed a copy of the rudder frame of the Contest 34 showing what is inside.

 

The rudder blade is built up from two halves, which before they were released were joined together by clamping the moulds.

The fill material is a mix of polyester resin and cement, which is a tough block when hardened.

The polyester halves are bounded by it as well.

After releasing the rudder, possible open seams and the open top were puttied in shape.

This putty was not of a quality which would stand the years below the waterline.

 

On the topic of corrosion; it might be so that inside the rudder blade there is no rust.

I enclosed a copy out of an American booklet which described why stainless steel rust near where it comes out of GRP or something.

If the resin/cement is still without any voids, I bet no unpleasant corrosion is enclosed.

But if the stock is heavy pitted above the rudder blade replacement is advisable.

 

Otherwise the cure you already mentioned, cover the blade with glass cloth and epoxy resin will be right measure.

 

I am only a humble draftsman, and not a specialist in boat repair, and it would be more prudent to contact Contest Yachts about this kind of things the next time!

 

Wishing you success with the repair.

Yours truly,

 

 

Dick Zaal.



Offline sjoerd

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Re: Contest Rudder Problems
« Reply #7 on: 10 July, 2013, 15:31:40 »
I think that a response like this proves that ALL the people behind the Contest's are indeed wonderful craftsmen and that they still provide value for our boats even when they are older.

This was a big thing for me when looking for our boat.

Sjoerd
SY Camelot
Contest 36S
Hull# 206
Fractional rig
http://www.sailingcamelot.nl

Offline jasn

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Re: Contest Rudder Problems
« Reply #8 on: 03 March, 2014, 00:35:23 »
Thanks for providing this information.

On my 1991 35S, I too have discovered that I have a crack that begins at the top of the rudder's leading edge, and goes all the way down to the bottom. I also think that the inside metal skeleton is likely fine, but my problem is that with this crack, the rudder's leading edge has spread out a little. This means when you turn the rudder to starboard all the way, (to turn to port), the rudder moves without issue. However, when you turn the rudder to port, (to turn to starboard), the added width of the leading edge rubs against the skeg.

So based on the information here, it's nice to see that the crack can simply be ground out and then patched to fix it. However, I think that I may need to sand down the rudder on the port side, along the leading edge, so that it stops rubbing against the skeg. Do I need to worry about sanding through the fiberglass? If I do, would the fix simply be to reapply fiberglass?

Lastly, I'm assuming that to work on the rudder, one should remove the barrier coat paint somehow. Once the rudder is fixed, the paint would need to be re-applied. If someone has any recommendations on what to use (for salt water), I would be interested in hearing about it.

Thanks,

Jason

Offline sjoerd

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Re: Contest Rudder Problems
« Reply #9 on: 03 March, 2014, 10:08:32 »
Hello Jason,

I think you can just shape the rudder and buidl it up with epoxy. This wil both provide a strong leading edge as well as form a strong bond to the old fiberglass. I would grind back quite considerabley so there'se lots of room to build up and shape the epoxy. You can use glassfibre ,atts in the initial layers if you like. I have done the same procedure on my previous boat (from aVERY repsectable swedish yard) and sailed around the atlantic with it.

Kind regards,

Sjoerd
SY Camelot
Contest 36S
Hull# 206
Fractional rig
http://www.sailingcamelot.nl

Offline jasn

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Re: Contest Rudder Problems
« Reply #10 on: 04 March, 2014, 03:28:50 »
Thank you Sjoerd,

I'm going to go ahead and use the method you describe. It was reassuring to read in this thread about the construction of the Contest rudder, and so I believe that it should be fairly straightforward to repair the crack in mine and then fair and shape the rudder with fiberglass and epoxy.

Jason

 


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