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-   -   Symmetric Rudder damage and surprise hardware! (http://www.sailnet.com/forums/gear-maintenance/114634-symmetric-rudder-damage-surprise-hardware.html)

Reefpoints 01-01-2014 04:42 PM

Symmetric Rudder damage and surprise hardware!
 
I've got a few questions for those with any insights, but let me explain the situation: When I first pulled the boat out of the water this year, I found it odd that the leaky/damaged spots on my rudder were exactly symmetric on the port/stbd side - see for yourself:

http://www.sailnet.com/forums/member...aks-damage.gif

When I started cutting into it (with an oscillating tool) I was surprised to find stainless steel nuts and bolts under the damaged weeping areas!! It is not in the foam-cored portion, but at the thick lower and leading edge of the rudder:

http://www.sailnet.com/forums/member...are-rudder.gif

So my thought is this - this hardware is not original, but some previous owner made some sort of poor make-shift repair with the hardware. Then over time, the bolts worked cracks into the rudder due to differing rates of thermal expansion between the epoxy (or vinylester?) and the stainless.

Questions:

1. Is my assumption above correct that this is a poorly executed repair and not original?

2. Is it okay to cut out and remove the hardware, or does it serve a valid purpose?

3. How best to repair this area? My inclination is to go and clean it out, fill it with epoxy thickened with colloidal silica and put a layer of glass and epoxy over both areas for strength. Does that sound about right?

Thanks all, and happy new year!

sony2000 01-01-2014 09:09 PM

Re: Symmetric Rudder damage and surprise hardware!
 
I think the hardware may be doing what it was intended to do, but the covering failed.
If it took ten years to fail, it may be worth doing it again, the same way, or with something insolating between the stainless and fiberglass.

paul323 01-01-2014 09:42 PM

Re: Symmetric Rudder damage and surprise hardware!
 
Just a thought - why cover the bolts? Yes, it may effect the flow of water over the rudder, but the stainless would be happier exposed (as opposed to being in an anoxic environment) and you would not have to worry about the covering cracking.

Reefpoints 01-01-2014 09:58 PM

Re: Symmetric Rudder damage and surprise hardware!
 
Insulating the steel between it and the epoxy (maybe with butyl tape) is a very interesting idea. I will think on that!

I didn't make it clear in my above post, but I planned on just cutting out the steel bolts entirely. They appear to be sandwiched in solid epoxy, it's not like it is joining anything that I can see. Since the rudder seems (overall) in fairly solid shape I thought at this point the hardware is redundant.

Has anyone seen anything like this before?

Faster 01-01-2014 10:21 PM

Re: Symmetric Rudder damage and surprise hardware!
 
If, in the course of cutting away material around the bolts it looks like molded recesses for the bolts themselves, it may have been an original way of joining the two halves of the rudder, not wishing to rely 100% on adhesives or glass...

Too bad Clark isn't still in business.

mitiempo 01-02-2014 12:32 AM

Re: Symmetric Rudder damage and surprise hardware!
 
I agree with Faster, it could be original. I would leave the bolts in place.

Butyl would be a poor choice because it never cures, is oil based, and epoxy will not stick to it. I would just make sure the recesses are cleaned well of foreign matter, acetone is good for this. Fill the recesses with thickened epoxy and it should last many years. Stainless steel fasteners are used successfully when hardware bonding with epoxy so there should not be any difference in this case. I have not heard of epoxy separating from fasteners like this - probably just poor execution when the recesses were filled.

I have a few tools that have had epoxy on their metal handles for a few decades with no sign of separating.

overbored 01-02-2014 02:26 AM

Re: Symmetric Rudder damage and surprise hardware!
 
Is it possible that the bolts are also part of the rudder shaft attachment to the rudder skins? I would make sure the shaft is still tight and refill the the depressions with thickened epoxy and an over lapping layer of light glass cloth. then go sailing for another 10 years. it does look like the way it was made by Clark and would have been filled originally with polyester filler back in the 80's

Gladrags1 01-02-2014 07:34 AM

Re: Symmetric Rudder damage and surprise hardware!
 
Inside the rudder would be a stainless steel backbone that he fiberglass is fashioned around. I agree with those who say to not remove the bolts as you may be creating more problems. The bolt further up the rudder is on the leading edge where the rudder shaft would be and the bottom bolts are where you would expect the bottom framework under the fiberglass skin to be. Inside rudders you have a framework that looks like a "b" with fiberglas around the lower rounded part.

Check for areas of water intrusion and seal to keep water out. This will eliminate freezing and further splitting.

Reefpoints 01-02-2014 09:00 AM

Re: Symmetric Rudder damage and surprise hardware!
 
Hmm, good points to think on - I had assumed it was a an aftermarket repair due to the fact that the "recesses" the bolts are in are roughly and irregularly shaped and a different color than the surrounding material. The basic structure is white while the area over the bolts is a gray-ish blackish color.

So, maybe the gray material is a previous owner's repair over the original hardware.

I suspect you all are right and it might be best to leave the hardware in place - I'll just put a lot of effort into making it very, very clean to ensure a good solid bond.

I was thinking of cutting in deeper to see what, if anything, the hardware is attached to, but now I think I'll skip that seeing as it may just weaken the rudder.

As always, thank you for your help!

I'll post final pictures when the repair is complete.

SJ34 01-02-2014 09:21 AM

Re: Symmetric Rudder damage and surprise hardware!
 
The bolts are original and joined the rudder halves. Before removing them I would recommend talking to Gene Adams at Port Gardner Sailboats. Gene was a San Juan dealer and worked very closely with the Clarks and was a consultant to San Juan MFG when they bought the Clarks out. I believe he still builds rudders for some of the boats.

I discovered water in my rudder 5 yrs ago and figure it was getting in at the top, past the rudder post. I sealed that and it's been dry since. Of course, my boat's in SoCal and has never frozen.


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