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Rudder Rebuild/Replace

Shelman

Member III
Blogs Author
I am currently building a new rudder for my 1985 E26 mkIII because it has a badly corroded shaft and a shrunken, deformed, bent blade. I have decided to make the switch over to 6061 T6 aluminum for the shaft and blade because my welder is set up for it. I can also add allot of strength with out adding any weight. I am leaning twards staying with the stock shape and size exactly, because I think it was designed really well. I am building the new rudder with a solid shaft made of bar stock 2-3/8" dia instead of the schedule 40 pipe filled with polyester resin.

My questions are:
1- Does anybody have any advice or experience in rudder shape and profiles design. naca 0012 ?
2- How many fellow Ericson owners have had to replaced their rudders?
3- how many have looked deeply at their rudder

The corrosion on the shaft was not visible until I scraped out some of the resin on the blade pretty deep.
On one side of the blade it is badly shrunken and the ribs are highly visible bumps.IMG_3604.jpg
IMG_3601.jpgIMG_3602.jpg
 

Alan Gomes

Sustaining Partner
I am currently building a new rudder for my 1985 E26 mkIII because it has a badly corroded shaft and a shrunken, deformed, bent blade. I have decided to make the switch over to 6061 T6 aluminum for the shaft and blade because my welder is set up for it. I can also add allot of strength with out adding any weight. I am leaning twards staying with the stock shape and size exactly, because I think it was designed really well. I am building the new rudder with a solid shaft made of bar stock 2-3/8" dia instead of the schedule 40 pipe filled with polyester resin.

My questions are:
1- Does anybody have any advice or experience in rudder shape and profiles design. naca 0012 ?
2- How many fellow Ericson owners have had to replaced their rudders?
3- how many have looked deeply at their rudder

The corrosion on the shaft was not visible until I scraped out some of the resin on the blade pretty deep.
On one side of the blade it is badly shrunken and the ribs are highly visible bumps.View attachment 14499
View attachment 14500View attachment 14501

I replaced mine in July of last year. The cost was $1150. I had them use sch. 80 pipe for the rudder post. I had it made by Foss Foam in Newport Beach.

When I reinstalled it I used stainless shim stock from McMaster-Carr, top and bottom, to dial in the fit.
 

Shelman

Member III
Blogs Author
rudder update

IMG_3661.jpgIMG_3670.jpgIMG_3706.jpgIMG_3701.jpgIMG_3711.jpg
Well.... The rudder is looking really good and in spite of being delayed into the summer and missing half of the sailing season because of it, I am really pleased with the way it turned out.
The rudder stock is solid bar aluminum 6061 t-6 and the blade skin is 1/4" plate marine grade (5052 or something like that.) and the frames are 3/16" marine grade.
The impact strength required to bend the new shaft (the only calculation that really matters in my mind) is many times higher than the original stainless shaft filled with epoxy. stainless steel 316 is actually really soft and although it takes a lot to actually break it off, it takes a lot less to just bend it. like happened to Allen Gomes's original one. the aluminum has a lesser final breaking strength because it will break instead of bending like the steel. it will take a greater impact before deforming I learned allot from the Jeffa rudders website and from many hours reading elsewhere online.
I really like the original rudder profile built by Foss Foam, and designed by I think it had a nice balance between strength and efficiency and power. The profile remains the same except I increased the surface area slightly(about an inch in chord and length) and used the NACA 0012 profile which is just a slight bit different shape than original.
I used a third of a pipe to skin the round leading edge and then shaped the one piece skins on either side by hand, very meticulously to match the entire rudder profile exactly. the first skin side I was able to weld to the frames from the inside and the second skin I attached by drilling 1/2" holes over the surface where the frames intersected and welded through the hole to the frame and then welded it closed. I welded a plate on the bottom and attached a teardrop shaped zinc for an anode.
I sanded the entire blade and coated it with fairing compound made from epoxy and micro balloons and then coated with several layers of thickened epoxy as a barrier layer so that I can apply anti-fouling paint without creating further problems with galvanic corrosion/electrolysis.
The whole thing cost me about $300 and took me the better part of a month working two nights a week on it, so it was not all that time consuming compared to some other lesser projects.
Thanks for the hint on the spacers Allen, that has helped me to get it adjusted just right.
 

Alan Gomes

Sustaining Partner
Impressive work, Shelman!

Nicely done! Congrats!

I'm not sure what I mentioned to you about my previous rudder but on mine not only was the post bent but the blade was also deformed very much along the lines of yours. I wonder what the deal was with that? That yours had the same issues is curious.
 
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Shelman,

Does this pic illustrate what was taken to be severe corrosion? I mean, is this what severe corrosion looks like?

shelmanIMG_3604.jpg
 

Shelman

Member III
Blogs Author
Yes. I have annother picture that shows the corrosion a bit better but I'm having difficulties posting. I'll try again later. It wasn't visible until I scraped away some gel-coat.
 

Shelman

Member III
Blogs Author
ericson rudder corosion.jpg this one is a little bit better. I can email you the full resolution if you would like. The corosion was enough to motivate me to action.
 

mkollerjr

Member III
Blogs Author
I know of an early 80's E38 owner who had his rudder snap off last year on a beam reach under full sail in 30 knots of wind off of the Washington coast. It sounded like water had penetrated the foam at some point and caused corrosion on the rudder post, where it failed. The photo of the remaining 25% rudder stub appeared to show some pretty bad corrosion (much worse than in Shelman's photos). Check your rudder posts for water intrusion!

Mark
 
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