Rudder shaft corrosion

[mpahl]

I'm pretty new to this boat- bought it last year. It's a 1977 Oday 27. The other day I dropped the rudder to facilitate replacing the cutless bearing and found some significant corrosion right at the waterline. I do not have the money to replace the rudder with a new one (1000+) and I don't have the time to rebuild the rudder right now, but I can do that this winter. So I need to get through this season.

Here's pictures of the corrosion: http://imgur.com/a/6X8X2

The shaft is 2"OD aluminium tube. The corrosion is in a 1/2" zone and at its worst, the shaft is down to 1.82" in the corroded zone. The walls of the tube are thick, ~.385".

My plan is to clean the inside of the shaft and have a solid aluminum rod machined to fit all the way down to the bottom of the shaft. I'll drive it in there with a bunch of epoxy and basically turn the thing into a solid rod. I can do all that for less than $100.

Just as a note, this boat has lived all its life in saltwater until now. The corrosion I'm seeing has probably been there for a long time and it's been sailed pretty hard during that time.

Any thoughts? Better repair options? Experience rebuilding the rudder?

 

[Rag Doll]

I'm pretty new to this boat- bought it last year. It's a 1977 Oday 27. The other day I dropped the rudder to facilitate replacing the cutless bearing and found some significant corrosion right at the waterline. I do not have the money to replace the rudder with a new one (1000+) and I don't have the time to rebuild the rudder right now, but I can do that this winter. So I need to get through this season.

Here's pictures of the corrosion: http://imgur.com/a/6X8X2

The shaft is 2"OD aluminium tube. The corrosion is in a 1/2" zone and at its worst, the shaft is down to 1.82" in the corroded zone. The walls of the tube are thick, ~.385".

My plan is to clean the inside of the shaft and have a solid aluminum rod machined to fit all the way down to the bottom of the shaft. I'll drive it in there with a bunch of epoxy and basically turn the thing into a solid rod. I can do all that for less than $100.

Just as a note, this boat has lived all its life in saltwater until now. The corrosion I'm seeing has probably been there for a long time and it's been sailed pretty hard during that time.

Any thoughts? Better repair options? Experience rebuilding the rudder?

Are you sure it's aluminum? I have a 1986 Oday 28 and the shaft portion is Stainless Steel 2" Diameter.

If it is Aluminum one option may be to find a Machine Shop/ Aluminum Welding capable (TIG Welder) and have them cut the shaft and weld in an extra heavy wall interior sleeve (not solid because aluminum creates a lot of heat transfer when welded) with a mid section to the O.D of your existing shaft (the sleeve would have to be long enough to eliminate distortion to the shaft). The area of corrosion would then be removed and the existing could be welded to the new sleeve with a full penetration weld. After welding the welds would have to be dressed down to the O.D. of the shaft. You will have to do some fiberglass work on the rudder but at least you know you have corrected the problem. They could weld this sleeve and the corroded area would be removed. The material Grade would need to be 6061 Aluminum.

Sleeving it the full lenght would probably work using epoxy but for the epoxy to adhere to both pieces needs to be very clean. How would you accomplish that? There is no gaurantee you have a absolute bond after all that work.

If anything since you have the rudder removed go to a machine shop and ask them. It will not cost as much as a new rudder. and if the shaft is Stainless Steel they could do the same process as describe above. If it is Stainless the grade wouls be most likely 316.

I hope this helped at least for a consideration.

 

[jbowersett]

If the wall thickness is truly 3/8, I think you would be okay for another season.Try to stay out of heavy wind (+20 knots) situations where you are hard on the wind, as this if where you will see the most force on the rudder also known as weather helm. And finally, start saving for a new rudder. Remember, the shaft has to fit in its hole without a lot of slop and welding that close to the rudder will creat a difficult area to clean up correctly. Also all that heat that close to the rudder is going to creat problems. Melting? Burning? Delaminating?
Good luck