Fellow Chrysler Sailors,
I thought I'd post a new topic so that others may learn from our experience (and mistakes!). We bought our 1978 C-26 a few years ago and have systematically gone through and renovated just about everything on the boat. Before the boat went in this season, I wanted to be sure and inspect a critical part of the boat not previously inspected--the rudder post assembly.
It took a lot to get the aluminum rudder post collar that sits below the tiller off. To remove the s.s. allen head bolts used to attach the aluminum collar to the s.s. rudder post required several rounds of heat and solvent to free them. The head of one broke off and the remainder had to be drilled out. This was the first clue to the problem of adjacent dissimilar metals without Tefgel or a similar barrier in place. Removal of the aluminum collar itself also required heat, solvent and impact.
After we dropped the rudder post, we were able to inspect the rudder bearings and other parts of the assembly. The lower bearing was badly cracked and seriously out of round, but the upper was not too bad, except for the accidental scorch from the blow torch when we were heating the aluminum collar. Both bearing seats will need some attention since they are grooved and have delaminating or missing gelcoat.
We noticed some heavy pitting on the head of the rudder pivot bolt when we removed the rudder in order to drop the assembly. This was bad, but just the first sign of corrosion problems we would discover. We noticed some tiny holes in the s.s. collar on the rudder post just above the rudder cheeks. They looked tiny on the surface, but probing with a screwdriver revealed much wider and deeper penetrations into the body of the metal. Upon doing some reading, this appears to be "pitting corrosion" which can cause serious structural problems as it travels well below the surface.
Once we started looking, we found a number of similar areas, but none as bad as that s.s. collar. From my reading on the subject, all this could be caused by one or more problems that we may have innocently/ignorantly contributed to:
1) Used 304 stainless fasteners below waterline. Somehow, when the boat was on the hard I didn't think of using 316? Duh.
2) Before launch 2008, I painted the rudder cheeks with antifouling paint without a metal primer applied first. The copper in the antifouling paint can promote galvanic corrosion between dissimilar metals.
3) We may have a wiring issue which could have resulted in stray current entering the water, though I'm not sure how. On my list before launch this year is to figure out why the bow/stern lights are not working, while the steaming light controlled by the same switch is.
4) No zincs on the rudder cheeks. Strangely, our rudder has a hole toward the aft portion which appears to be intended for a zinc. We attached one, but from what I've read the zinc needs to be in contact with metal (not the fiberglass rudder) to do its intended job.
It's a good thing we inspected all this before going in the water this year. You will see from the pictures I've posted, that the bolts were not far from becoming useless. Leaving all the same as last year could have resulted in loss of the rudder and/or use of the control lines (for what they're worth).
Our plan for repairs/remedy are as follows:
1) Grind out pits and fill all pits with epoxy/silica mixture.
2) Remove antifouling paint and use a metal primer intended for submersion before reapplication of antifouling.
3) Attach zincs at rudder pivot bolt and rudder control line spacer bolts ensuring bare metal contact.
4) Inspect and fix wiring issue with bow/stern lights.
5) Replace all fasteners with 316 stainless steel.
6) Inspect rudder assembly annually.
I know the epoxy is probably a temporary fix, but short of filling the holes with weld, it's probably the best approach. From what I can tell, the s.s. collar above the rudder cheeks acts as a spacer and does not appear integral to the structure of the rudder assembly. If others have other suggestions for repairs I'm all ears!
Please see photos at http://www.flickr.com/photos/36339036@N ... 264580528/
Best wishes for happy and safe sailing!
Evil Electrolysis - Don't let this happen to you!
Evil Electrolysis - Don't let this happen to you!
eamac
s/v Bay Tripper
1978 C-26
s/v Bay Tripper
1978 C-26
-
EmergencyExit
- Site Admin
- Posts: 2954
- Joined: Wed Dec 10, 2003 5:02 pm
- Location: Mississippi Gulf Coast
Whoa. Great post ! And good info. I have to confess I applied bottom paint to my rudder cheeks and never thought of the galvanic possibilities.
I hauled out this week to hang my repaired outboard (kinked my back lowering in over the transom last time), and to retrieve my lost control lines ( as you say, for what they are worth). I washed her down and all my antifoul on the rudder cheeks washed off. Glad it did now.
My lower mushroom bearing is broken, I 5200'd it for now. Planning another haulout for hot July to address that.
I hauled out this week to hang my repaired outboard (kinked my back lowering in over the transom last time), and to retrieve my lost control lines ( as you say, for what they are worth). I washed her down and all my antifoul on the rudder cheeks washed off. Glad it did now.
My lower mushroom bearing is broken, I 5200'd it for now. Planning another haulout for hot July to address that.
OH BOY! Now you've done it.... I have been putting off a rudder job for many seasons now... originally worried about the fragility of the blade -- fearing it water logged, then worried about the thru-hull assembly.. now this! I bought new rudder bearngs and new tiller from IdaSailor.. but have put it all off since I thought I should do it all at once and then it became a bigg job... IdaSailor wants 999 just for the MDF blade, and Foss wants 1000 to do a full blade and SS stock assembly.. i could not decide over the ease of the OEM R/R Ida Sailor blade vs dropping the whole assembly Foss R/R... now I see I should probably get a whole new blade and stock set-up from Foss ( also saw some pics of the IdaSailor MDF blade splitting in two.. not cool for a 1000 rudder blade) and deal w/this... How many feet did you need to drop the assembly... I would hate to have to hang in the yard slings while I do this time comsuming task...also the yard does not permit me to do any work below the waterline..unreal...so they are chomping at the bit to do this job for me at $90/hr labor + materials + parts... ( still lookign for a trailer).. also the electrolosys could be coming from stray voltage from a neighbor slip ( bilge pump ) or even the marina ..
thanks for the pics and I alwyas thought getting the tiller collar off would be the easiest part... on my assembly the lower collar is up near the hull and I always thoguht it was to hold the bearing in or to keep the stock from riding up..
thanks for the pics and I alwyas thought getting the tiller collar off would be the easiest part... on my assembly the lower collar is up near the hull and I always thoguht it was to hold the bearing in or to keep the stock from riding up..
NYC Sailor,
With regard to your question about the distance required to drop the assembly. We have the boat on stands in the yard and had to dig a hole about 1 foot deep and wide to remove the rudder assembly. I am not sure of the exact distance and this would certainly depend on the height of your stands if you're on the hard. I remember reading 51" in another post as the required distance to drop the assembly, but we didn't measure. If you can't do work below the water line, I don't know how you'd do this job yourself. If you did, you would probably do best to remove the rudder before dropping the assembly as it would be prone to float and fight you trying to remove the assembly. After removing the rudder, I would tie a safety line through the hole in the rudder cheeks to prevent the whole thing from going to the bottom as it's pretty heavy. I am not sure if water would get into the boat.
A couple of other points on this whole issue of electrolysis worth mentioning:
1) I once thought the rudder cheeks were aluminum, but I don't think this can be the case as they are welded to the s.s. rudder post. I'm no expert, but I don't think it's common practice to weld dissimilar metals together. Also, this would create a galvanic corrosion nightmare. Thus, all rudder assembly parts are s.s. so there really aren't any dissimilar metals below the waterline. Certainly, the alloys of each part could be different providing differing potential for corrosion, but what was different this year compared to last? The wiring issue and anti-fouling paint.
2) Use of nylon washers under the s.s. washers may have isolated them from the copper of the anti-fouling paint. Didn't think of it, since I didn't think of the problem.
3) We are on a mooring, so are not plugged in to AC shorepower, though the boat is wired for it. Could stray current from boats moored nearby still be an issue?
4) Obviously, we are in saltwater and I don't believe electrolysis is as much of an issue in fresh water.
5) You'll notice from the pictures that the areas of the 1/4-20 bolts under the Nylock nut are more corroded than the rest of the bolt. From what I've read, this is because of the occlusive nature of the Nylock. Apparently, s.s. requires oxygen to maintain its "stainless" character and the Nylock reduces the ability of oxygen from getting to the bolt. I think I will still use Nylocks, but inspect every year.
We have a s.s. fastener company in our town and I brought the bolts in to show the owner. He recognized the damage immediately as caused by electrolysis. He says it is a major issue and mentioned that lobsterman have told him that when they pull up their wire pots, they can hear them humming from all the electrolysis going on. These are pots that are on the bottom of the ocean, not near marinas, so the stray AC current from shorepower should not be a concern.
Scary stuff!
With regard to your question about the distance required to drop the assembly. We have the boat on stands in the yard and had to dig a hole about 1 foot deep and wide to remove the rudder assembly. I am not sure of the exact distance and this would certainly depend on the height of your stands if you're on the hard. I remember reading 51" in another post as the required distance to drop the assembly, but we didn't measure. If you can't do work below the water line, I don't know how you'd do this job yourself. If you did, you would probably do best to remove the rudder before dropping the assembly as it would be prone to float and fight you trying to remove the assembly. After removing the rudder, I would tie a safety line through the hole in the rudder cheeks to prevent the whole thing from going to the bottom as it's pretty heavy. I am not sure if water would get into the boat.
A couple of other points on this whole issue of electrolysis worth mentioning:
1) I once thought the rudder cheeks were aluminum, but I don't think this can be the case as they are welded to the s.s. rudder post. I'm no expert, but I don't think it's common practice to weld dissimilar metals together. Also, this would create a galvanic corrosion nightmare. Thus, all rudder assembly parts are s.s. so there really aren't any dissimilar metals below the waterline. Certainly, the alloys of each part could be different providing differing potential for corrosion, but what was different this year compared to last? The wiring issue and anti-fouling paint.
2) Use of nylon washers under the s.s. washers may have isolated them from the copper of the anti-fouling paint. Didn't think of it, since I didn't think of the problem.
3) We are on a mooring, so are not plugged in to AC shorepower, though the boat is wired for it. Could stray current from boats moored nearby still be an issue?
4) Obviously, we are in saltwater and I don't believe electrolysis is as much of an issue in fresh water.
5) You'll notice from the pictures that the areas of the 1/4-20 bolts under the Nylock nut are more corroded than the rest of the bolt. From what I've read, this is because of the occlusive nature of the Nylock. Apparently, s.s. requires oxygen to maintain its "stainless" character and the Nylock reduces the ability of oxygen from getting to the bolt. I think I will still use Nylocks, but inspect every year.
We have a s.s. fastener company in our town and I brought the bolts in to show the owner. He recognized the damage immediately as caused by electrolysis. He says it is a major issue and mentioned that lobsterman have told him that when they pull up their wire pots, they can hear them humming from all the electrolysis going on. These are pots that are on the bottom of the ocean, not near marinas, so the stray AC current from shorepower should not be a concern.
Scary stuff!
eamac
s/v Bay Tripper
1978 C-26
s/v Bay Tripper
1978 C-26
When I did my rudder repair, I just cut the aluminum ring and I had one made out of SS, and I the allen screws I used where also SS. Below the water line, I added some aluminum (I wish I had the photos) Also what I did, I replaced the tube for the rudder with a piece of PVC and I glassed everything including the plastic mushrooms.
1976 Chrysler 22 Halve Maen - Sail # 595
Hi Gus,
Good idea on cutting the aluminum ring. I plan to replace this with a s.s. ring to avoid the dissimilar metals problem in the future. It would have made sense for Chrysler to do this from the get go.
Regarding the addition of aluminum below the waterline-that's another great idea since it has similar sacrificial qualities as zinc, but for a lot less weight. I was thinking of adding a piece of alum. rod or pipe cut the long way at the space along the rudder post where the cheeks are welded on. There are factory mount holes there for something, but whatever it was it's long gone. The half rod/pipe would act as an anode and perhaps reduce drag a little since this area must be a bit like a scoop going through the water. Hopefully, 6061 aluminum will suffice.
I like the idea of the PVC pipe instead of the heater hose on the interior, but this will have to wait until another time. This rudder job will set us back some on pre-launch time and there's more to be done. Hopefully, future rudder disassemblies will be less involved!
Good idea on cutting the aluminum ring. I plan to replace this with a s.s. ring to avoid the dissimilar metals problem in the future. It would have made sense for Chrysler to do this from the get go.
Regarding the addition of aluminum below the waterline-that's another great idea since it has similar sacrificial qualities as zinc, but for a lot less weight. I was thinking of adding a piece of alum. rod or pipe cut the long way at the space along the rudder post where the cheeks are welded on. There are factory mount holes there for something, but whatever it was it's long gone. The half rod/pipe would act as an anode and perhaps reduce drag a little since this area must be a bit like a scoop going through the water. Hopefully, 6061 aluminum will suffice.
I like the idea of the PVC pipe instead of the heater hose on the interior, but this will have to wait until another time. This rudder job will set us back some on pre-launch time and there's more to be done. Hopefully, future rudder disassemblies will be less involved!
eamac
s/v Bay Tripper
1978 C-26
s/v Bay Tripper
1978 C-26
-
EmergencyExit
- Site Admin
- Posts: 2954
- Joined: Wed Dec 10, 2003 5:02 pm
- Location: Mississippi Gulf Coast
50" inches was what it took to remove EE's rudder assembly. Breakdown pics are here:
http://my.att.net/p/s/community.dll?ep= ... 301349&ck=
eamac, those holes you mention are for a fairing such as you describe, read somewhere that the original was wood.
http://my.att.net/p/s/community.dll?ep= ... 301349&ck=
eamac, those holes you mention are for a fairing such as you describe, read somewhere that the original was wood.
I'm going to try to attach a crude diagram I made of my rudder assembly.eamac wrote:Hi Gus,
Good idea on cutting the aluminum ring. I plan to replace this with a s.s. ring to avoid the dissimilar metals problem in the future. It would have made sense for Chrysler to do this from the get go.
Regarding the addition of aluminum below the waterline-that's another great idea since it has similar sacrificial qualities as zinc, but for a lot less weight. I was thinking of adding a piece of alum. rod or pipe cut the long way at the space along the rudder post where the cheeks are welded on. There are factory mount holes there for something, but whatever it was it's long gone. The half rod/pipe would act as an anode and perhaps reduce drag a little since this area must be a bit like a scoop going through the water. Hopefully, 6061 aluminum will suffice.
I like the idea of the PVC pipe instead of the heater hose on the interior, but this will have to wait until another time. This rudder job will set us back some on pre-launch time and there's more to be done. Hopefully, future rudder disassemblies will be less involved!
The aluminum is attached to the rudder with some screws. I also when I cut the aluminum ring out of my rudder, I took it to the machine shop and they made an exact copy out of SS. I have to look at my boat, but I don't remember if I used the allen nuts they gave me, or regular SS screws. I replaced the hose with the PVC because first it leaked bad, and second, I didn't like the idea of having something like that instead of a solid connection between the hull and the cockpit. Also, it didn't took me that long to make that mod, most of the time was spent taking the rudder off and preparing the area, and waiting for the epoxy to kick.
Good luck!
1976 Chrysler 22 Halve Maen - Sail # 595
Gus,
Thanks for sharing your diagram. It looks as though you used sheet aluminum at the forward position on the rudder. Do you get a lot of growth in the space between the fairing and the rudder post?
I took the aluminum collar to our local metals shop today to see if they could make it out of s.s. They said they could but will give me a quote first. Half inch s.s. probably won't be cheap, but it's probably worth it.
I will post pics of the completed project when complete.
Thanks for sharing your diagram. It looks as though you used sheet aluminum at the forward position on the rudder. Do you get a lot of growth in the space between the fairing and the rudder post?
I took the aluminum collar to our local metals shop today to see if they could make it out of s.s. They said they could but will give me a quote first. Half inch s.s. probably won't be cheap, but it's probably worth it.
I will post pics of the completed project when complete.
eamac
s/v Bay Tripper
1978 C-26
s/v Bay Tripper
1978 C-26
No, not really a lot of growth, I did get some thing attached to the aluminum the first time I went out, but it washed right off when I pulled the boat off the water.
I can't remember how much it was when they did the SS collar for me, because they did other things for me, but I think the collar and the aluminum wedge and something else, I can't remember what, was like 150 bucks or so.
I can't remember how much it was when they did the SS collar for me, because they did other things for me, but I think the collar and the aluminum wedge and something else, I can't remember what, was like 150 bucks or so.
1976 Chrysler 22 Halve Maen - Sail # 595
When I first started to contemplate fixing my rudder up it had a large round zinc on one side and i thought it was just a washer to reinforce the ss plate. Then i saw the same large zinc at West Marine and it hit me (Boat spent most of it's early life in the water). The last paint job had painted the ss but i removed it all and polished it then left it be. Since my boat does not sit in the water i don't have to worry about the problem anymore.