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1 . 
  S&S Swan Maintenance - Loose rudder on S&S 40
 
 
 
31 July 2007 - 21:08
#1
 
  peter J. Lange Join Date: 31 July 2007
Posts: 52
 
  Loose rudder on S&S 40  
 

Last year when I hauled out, I observed that the rudder is loose on the shaft. It moves from side to side about 12 mm measured at the end of the blade. The play comes from the keys being loose on the rudder stock. The rudder stock is a solid shaft 40 mm diameter from the cockpit down to the lower bearing that is attached to the skeg and takes the downward load. There are two straps, 60 mm wide and 250 mm long that hold the rudder blade. The straps wrap around a sleeve. The rudder stock goes thru the sleeve. There is a 8 mm key that transmits the turning force from the shaft to the rudder. Because there are two straps, I assume there are two keys, one in each sleeve. The looseness is between the shaft and the sleeves. This year, when I hauled out, there was no increase in looseness; it was the same, but I have not used the boat either. In the past, when I did build rudders, I would bend the shaft about 45? about 5 inches from where it comes out of the hull and machine a flat on the end of the bend, so that I could taper the rudder. When it was embedded into the rudder blade, it became a solid assembly. With this key arrangement, there must have been some clearance initially to assemble it. Over the years the play is probably increasing, or maybe, I never noticed it before. Your suggestions/comments are invited please!

 

 

 
     
 

 
     
 
 
01 August 2007 - 16:22
#2
 
  hnakajima Join Date: 20 February 2007
Posts: 116
 
 

I had the same identical issue on my 1969 Swan 43. The keyway on the rudder stock and key develop wear over time and results in the rudder movement. I suspect this was a very tight pressure fit initially at the factory but over time it develops slop.

I made repairs by welding the strap bushings directly to the rudder shaft.  Don't forget to inspect the lower bearing on the bottom of the rudder skeg.  This can also develop wear and induce lateral (side-to-side) play of the rudder stock.

It appears that all of the older Swans are exhibiting this issue.

See forum discussions dated February 20, 2007 and March 19, 2007 for pictures and discussions.

H. Nakajima

 

 
     
 
 
03 August 2007 - 13:20
#3
 
  peter J. Lange Join Date: 31 July 2007
Posts: 52
 
 

Dear Nakajima-san: I have heard of such a repair from another owner of a S&S43. His name is Robert Ahabel. The repair was done in Sausalito, CA but I can not find out exactly how it was done because a shipyard did it. You are quite possibly right that it is a condition that affects these models and it becomes worse as time goes on. Did you remove the entire rudder assembly from the boat and then remove the rudder blade? Did you experience distortion from the welding? Did you stick-weld or heli-arc TIG weld? Did you passivate the assembly after welding? Did you find corrosion? How long did it take you? The answer to that question determines what kind of arrangements I have to make to keep the boat out of the water. Thank you very much for sharing your knowledge!

 

 
     
 
 
03 August 2007 - 22:07
#4
 
  hnakajima Join Date: 20 February 2007
Posts: 116
 
 

Dear Mr. Lange or Lange-san:

 

I performed the rudder repair work myself except for the welding component and can say that the repair is very straight forward and can be done in about 5-7 days time.

 

To properly weld the strap bushings to the rudder stock the entire rudder assembly should be removed from the boat.

 

Removal of the rudder assembly goes quite quickly.  First remove the rudder quadrant and loosen the rudder stuffing box.  Next grind away the fiberglass fairing at the bottom tip of the skeg to expose the cast bronze shoe which supports the bottom of the rudder stock.

 

Remove the 4-5 bolts securing the bronze shoe to the fiberglass skeg.  You may need to heat up this shoe with a hand held torch to release any epoxy used to secure the bronze shoe to the skeg.  Be very gentle here not to heat distort or hammer distort this shoe since this is a custom Swan casting and not overly robust.

 

Once the bronze shoe has been freed the entire rudder assembly should slip out.  Have a helper here since my rudder assembly weighed about 90 pounds.

 

Once the rudder assembly is off the boat remove the stainless steel shrouds covering the stainless steel rudder stock along the leading edge of the rudder blade.  Next grind away the fiberglass fairing to expose the stainless steel straps holding the fiberglass rudder blade.  Remove the stainless steel bolts from the strapping and the fiberglass rudder blade should separate from the strapping.

 

Clean the stainless steel rudder stock, strapping, etc with a wire brush wheel on a grinder.  You will probably see numerous areas of crevice corrosion and pitting.  The factory rudder stock is 40mm and I concluded that this is a very conservative design and unless I saw an obvious area of concern the shaft, although not pretty, was structurally OK for another 37 years.  Also one should keep in mind that unlike contemporary spade rudder designs the older Swans have skeg hung rudders where the bottom of the rudder stock is supported by a bottom shoe and at the top so dynamic loads are supported at two locations.

 

I had my local rigging shop perform a TIG weld to continuously weld the top and bottom faces of both the upper and lower strap bushings.  The welds were then ground smooth.  Before you have the bushings welded double check their alignment and location with the rudder blade.  I had to re-weld one of my bushings due to a slight mis-alignment.

 

Passivating would not hurt but I did not have enough time so I did not do this. 

 

Re-assembly is reverse of dis-assembly.  Make sure to replace all stainless steel bolts with new.  Per Swan factory technical director?s direction all bolts should be torqued into place using a wrench on a double nut arrangement.  Using a screw driver is totally inadequate.

 

I also replaced the bushing/bearing in the cast bronze shoe with a composite unit from this web-site http://www.garlockbearings.com.  Again per Swan factory technical director?s comments do not use Teflon since this will expand when in contact with water and may cause binding and also not to use any graphite type material against stainless steel as this may promote crevice corrosion.

 

The time consuming component for me was the re-fairing of the rudder blade at the straps, shrouding of the rudder stock and the cast bronze shoe.  I am pretty finicky about these and it took multiple applications over a course of 3-4 days to achieve satisfactory results.

 

I have attached photos for your info.

 

Good luck.

 

Happy to answer any questions.  Hiro

 
     
 

 
     
 
 
04 August 2007 - 19:32
#5
 
  peter J. Lange Join Date: 31 July 2007
Posts: 52
 
 

Thank you Hiro for your detailed reply and instructions. That is exactly what I had hoped for. Someone who has done the job and taken pictures like you did. It will make it so much easier for me. Thank you!

Pete

 
     
 
 
31 October 2011 - 21:27
#6
 
  Peter J. Lange Join Date: 31 July 2007
Posts: 52
 
  Original message:

Thank you Hiro for your detailed reply and instructions. That is exactly what I had hoped for. Someone who has done the job and taken pictures like you did. It will make it so much easier for me. Thank you!

Pete




 
 
Dear Nakajima-san:
Back in 2007 you explained to me how you repaired the loose rudder on your Swan 43. You also said, you had tried to pin it first, but that did not work: The pins sheared. So, How is the welding holding up after all these years? I have not used my boat because I had to take care of my wife. She died this year and I am addressing the loose rudder on my boat again. Just want to know how your repair held up. Also, your photograph shows that you did not weld all around. Is that what you recommend? Maybe, because welding tends to pull or distort things, and also because welding may cause a notch effect, you did not weld all around. You also mentioned that after welding you noticed a slight misalignment and had to correct that. Do you think it would be good to tack-weld before I remove the rudder blade? It appears that would prevent subsequent misalignment. Thank you very much and I really appreciate that you allow me to draw on your experience! Thank you!
 
     
 
 
02 November 2011 - 19:41
#7
 
  the professor Join Date: 02 January 2008
Posts: 1173
 
 
Pete and Hiro
Thank you for the information
I would like to add some comments.
The information referring to Teflon bearing sleeves was given by Matteo, and he also stated that POM is a suitable material.
The rudder strap sleeves have originally been shrink-fitted onto the stock by heating them. The resulting joint tightness is very dependent on the tolerances of the components, and am afraid the importance of this was not quite understood in the beginning.
If you choose to weld the sleeves to the stock, the shop doing this must be aware of the risk of weld decay, scientific name carbide precipitation, associated with welding of stainless steel. Weld decay causes catastrophic corrosion in the weld area.
Very strong anaerobic glues are available now, and I had a look at gluing the sleeves to the stock. A calculation suggests that 4 MPa glue shear strength would cope with a 400 N (90 lbs) load on the wheel rim. I think some Loctite glues are much stronger than that, suggest you discuss this with the local Loctite rep.
There may be practical problems with cleaning the surfaces and getting the glue into the narrow slot, but it would certainly be interesting to get their opinion for such an application.
Best regards
Lars
 
     
 
 
03 November 2011 - 01:52
#8
 
  Peter J. Lange Join Date: 31 July 2007
Posts: 52
 
 
Dear Professor Lars:
As you know, I have had my share of corrosion of welds on stainless, especially on my muffler. The welding changes the stainless and the weld becomes magnetic. Crevice corrosion sets in and the now corroded area has a different electrical potential. Galvanic corrosion follows. Hell of a thing. I like to avoid welded areas exposed to salt water. I made a spade rudder for my boat. Used a monel shaft and bent it about 45 degrees. The bent part is embedded in the rudder. The rudder core is Airex. Problem is, the rudder vibrates under power. But it steers the boat very nicely. So I have another rudder when I pull the original one and it takes the pressure off to get the rudder repair done quickly. I can still use the boat. Your suggestion to use anerobic adhesive is interesting. Have to do research. What I would have liked to see is a slightly smaller diameter of the stock before the press-fit area. Just dreaming! I'll get some more ideas when I have the rudder in the shop and can see how the original welding between the bushing and the strap is holding up. What I have designed in the past sometimes for reciprocating loading is two keyways toleranced in such a way they load each other. Very common in gear trains. I hope that Hiro comes back with some service experience of his repair. Nothing like learning from others. Hope you are well!
 
     
 
 
04 November 2011 - 10:24
#9
 
  the professor Join Date: 02 January 2008
Posts: 1173
 
 
Pete
If your spade rudder stock is 40 mm this sounds marginal, depending on rudder size.
Vibration is likely to be caused by leading or trailing edge shape, could you describe them?
Best regards
Lars
 
     
 
 
06 November 2011 - 07:04
#10
 
  Peter J. Lange Join Date: 31 July 2007
Posts: 52
 
 
Dear Lars:
Thank you for responding to my post about the rudder. Here is some clarification: The spade rudder I built is separate from the standard rudder. It installs with the shaft vertical about four inches forward of the backstay tang on deck, thru a bronze packing fitting glassed into the hull. Iíll post a pic when I have an opportunity, but it is not installed at this time. I used it to be actuated by an autopilot actuator made by Autohelm. Thatís what the small arm shown on the photograph is for. I made a tiller for it for hand steering or to connect a wind vane. The tiller, when itís all the way down, just clears the wheel. The rudder blade is 41 inches long and 15 inches fore & aft. Yes, it is small, but it's way aft and fully submerged when the stern wave comes up. The shaft is 1 3/8 diameter and is Monel K500. It has a yield strength about three times of 316 L stainless. Before I used the shaft, I cut off a test slug and had it brinell tested to confirm the advertised yield strength. The test indicated 150,000 PSI Yield. I sea-tested the arrangement and it steers the boat very well, lots of control and good feel. The rudder vibrates a little when running under power. I can feel the prop wash off the two blade folding propeller. When the autopilot actuator steers, the vibration is not noticeable. I plan on using this rudder when I remove the standard rudder for repairs. It will take the time element away. I can take a year for the repair. Your suggestion to use an anaerobic adhesive is well worth considering. Iíll know a lot more after I remove the rudder and Iíll keep you posted.
 
     
 

 
     
 

 
     
 
 
 
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