Rudder rebuild?

[Searles]

Recently came across a C/T 41 with a rudder rotten to the core ,it was all corse grain plywood with steel palms welded to a s/S rudder stock ,the ply had been shaped,quite nicely infact,then glassed over with chopped strand mat and Polly resin about 5/16 thick ,this rudder has had miltipull repairs bur its 40 plus years old, result a completely new rudder ,every thing replaced including bearings .⛵️⚓️

[MicHughV]

These are always interesting topics.

When faced with a sudden unexpected, but likely outlay of major time and $$$, one tends to look for "miracles" where there are none.

A rudder is very much like a steering wheel on a car, without it, you can't do anything, even if the car is in mint condition otherwise.

The pics clearly indicate some investigative work needs to be done, after which a remedial repair can be be planned.

I hope the OP will post more pics once the " investigative" work is done as I plan to save this thread in my box of " unexpected repairs that needed to be done" for future reference.

[JD-MDR]

Just contributing to the conversation: I didn't have much problem with the laminate or core, it was the post that was deteriorated. I notices a little seepage at where the post exits the rudder

[Wolfe10]

Originally Posted by JD-MDR

Just contributing to the conversation: I didn't have much problem with the laminate or core, it was the post that was deteriorated. I notices a little seepage at where the post exits the rudder

Sure looks like electrolysis damage.

[JD-MDR]

Originally Posted by Wolfe10

Sure looks like electrolysis damage.

I'm sure there was some electrolysis in the harbor.. there was no electronics on the boat that sat for ten years. I was told that old water with decomposing organisms in the shaft log was probably the main cause

[Searles]

Yep stale or highly saline salt water will do this every time ,same with encapsulated chain plates ,it never stops .⛵️⚓️

[Bigjim]

Originally Posted by MicHughV

These are always interesting topics.

When faced with a sudden unexpected, but likely outlay of major time and $$$, one tends to look for "miracles" where there are none.

A rudder is very much like a steering wheel on a car, without it, you can't do anything, even if the car is in mint condition otherwise.

The pics clearly indicate some investigative work needs to be done, after which a remedial repair can be be planned.

I hope the OP will post more pics once the " investigative" work is done as I plan to save this thread in my box of " unexpected repairs that needed to be done" for future reference.

I plan on following this through. But I have to wait until temperatures get above freezing constantly so I don't have to deal with frozen water.

[Bigjim]

Originally Posted by JD-MDR

Just contributing to the conversation: I didn't have much problem with the laminate or core, it was the post that was deteriorated. I notices a little seepage at where the post exits the rudder

I do not see any type of electrolysis on any exposed metal below the water line. The damage at the moment seems to be isolated to the fiberglass.

[boatpoker]

Originally Posted by Wolfe10

Sure looks like electrolysis damage.

Be wary of corrosion or electrical advice from anyone using the word "electrolysis" on boats.

Electrolysis is an induced process found in industry and laboratories in which the anode is positive and the cathode is negative.

The corrosion involving electricity on boats falls into two broad categories ... Stray Current and Galvanic Corrosion. in both of these types the anode is negative and the cathode positive - the exact opposite of "electrolysis".

The corrosion seen on that shaft photo is simple pitting corrosion from lack of oxygen.

[boatpoker]

Originally Posted by Bigjim

I do not see any type of electrolysis on any exposed metal below the water line. The damage at the moment seems to be isolated to the fiberglass.

The vast majority of pitting corrosion will be inside the metal, inside the rudder where water has been sitting and turned stagnant (deoxygenated).

The photos below shows an x-ray of a single pinhead sized pit and what the shaft looked like on the inside when it broke.

[Cheechako]

Originally Posted by Bigjim

I plan on following this through. But I have to wait until temperatures get above freezing constantly so I don't have to deal with frozen water.

It looks pretty rough surface. That may indicate some big problems inside. Do you store on the hard in freezing winters?

I rebuilt the water logged rudder on the boat in my avatar, but it was nice and smooth still. I would have never known if I hadn't drilled a hole in the bottom of the rudder and water came out for days. The boat was about 8 years old at the time. Interestingly, the next boat I purchased had a water logged rudder and it was 6 years old at the time.

-I simply cut a large window on one side and pulled out that rectangle.
-I then scraped out all the mush inside and let it dry for a couple of weeks.
-I did not find any corrosion in the SS structure and looked closely. A couple key areas I used Zyglo Penetrant inspection with a black light for assurance.
-It's amazing how water gets into all these rudders. There were no ingress points in this rudder and the shaft was glassed tightly to the rudder. But obviously it had to come in there.
-After full dry out I glassed the rectangle back onto the rudder.
-I then filled the rudder via two 3/4" holes I had cut in the top of the rudder. I filled it completely up with a product called "Rudder cast". A Blue/Green color casting epoxy blend made for actually casting powerboat rudders in a mold. No longer sold that I know of.
-It turned out perfectly and lasted 25 years last I heard from a survey a few years back.

The epoxy weight was very negligible really. IIRC it was about 4-5 gallons? So maybe 30#-35#?. Maybe in water it was bouyant?

[Bigjim]

Originally Posted by Cheechako

It looks pretty rough surface. That may indicate some big problems inside. Do you store on the hard in freezing winters?

I rebuilt the water logged rudder on the boat in my avatar, but it was nice and smooth still. I would have never known if I hadn't drilled a hole in the bottom of the rudder and water came out for days. The boat was about 8 years old at the time. Interestingly, the next boat I purchased had a water logged rudder and it was 6 years old at the time.

-I simply cut a large window on one side and pulled out that rectangle.
-I then scraped out all the mush inside and let it dry for a couple of weeks.
-I did not find any corrosion in the SS structure and looked closely. A couple key areas I used Zyglo Penetrant inspection with a black light for assurance.
-It's amazing how water gets into all these rudders. There were no ingress points in this rudder and the shaft was glassed tightly to the rudder. But obviously it had to come in there.
-After full dry out I glassed the rectangle back onto the rudder.
-I then filled the rudder via two 3/4" holes I had cut in the top of the rudder. I filled it completely up with a product called "Rudder cast". A Blue/Green color casting epoxy blend made for actually casting powerboat rudders in a mold. No longer sold that I know of.
-It turned out perfectly and lasted 25 years last I heard from a survey a few years back.

The epoxy weight was very negligible really. IIRC it was about 4-5 gallons? So maybe 30#-35#?. Maybe in water it was bouyant?

Excellent info. I can't check for water until the temps rise above freezing for a week or more. As for how the water gets in, it doesn't take much space. My rudder looks like it also has a tight interface to the shaft, but as you sail and go through the water, the minute vibrations can open up tiny microscopic cracks. Any amount of water that gets in, will stay there until you pull out of the water. If it doesn't drain or evaporate before winter hits, it will freeze in place and then expand. Since the boat is 44 years old, that process has been repeated every year. The once microscopic cracks enlarge to visible fissures and it continues to get worse until one day when you eventually will have a major failure at some point.

FYI, I did drill a hole or two the first fall when we pulled, but no water came out. Obviously, this process is like looking for oil. Lots of teams drill for oil but often the holes are dry. As you can see from my photos, the damage is not consistent. So, water did not get into the entire structure. I have a moisture meter, so as soon as the temperature rises again, I'll check the rudder to see where the most moisture is, if any.

If I designed the rudder, I would have incorporated a drainage system where you could remove the entrained water at some point. Sure, you don't want it there in the first place, but it's going to get in there at some point and there should be a method to remove it, like we have pumps for the water that gets in our bilges.

One idea I'm kicking around is using penetrating epoxy and vacuum infusion. First, I would carve out all the damage, rebuild all those areas. Put the rudder in a bag and set up my vacuum pump to first suck out any remaining water. Then, set up a reservoir of penetrating epoxy to fill any voids with epoxy. I think this would give the existing rudder a new life for another 10-20 years. Finally, I would caulk the interface where the shaft meets the rudder to try to keep water out going forward.

[Cheechako]

Originally Posted by Bigjim

Excellent info. I can't check for water until the temps rise above freezing for a week or more. As for how the water gets in, it doesn't take much space. My rudder looks like it also has a tight interface to the shaft, but as you sail and go through the water, the minute vibrations can open up tiny microscopic cracks. Any amount of water that gets in, will stay there until you pull out of the water. If it doesn't drain or evaporate before winter hits, it will freeze in place and then expand. Since the boat is 44 years old, that process has been repeated every year. The once microscopic cracks enlarge to visible fissures and it continues to get worse until one day when you eventually will have a major failure at some point.

FYI, I did drill a hole or two the first fall when we pulled, but no water came out. Obviously, this process is like looking for oil. Lots of teams drill for oil but often the holes are dry. As you can see from my photos, the damage is not consistent. So, water did not get into the entire structure. I have a moisture meter, so as soon as the temperature rises again, I'll check the rudder to see where the most moisture is, if any.

If I designed the rudder, I would have incorporated a drainage system where you could remove the entrained water at some point. Sure, you don't want it there in the first place, but it's going to get in there at some point and there should be a method to remove it, like we have pumps for the water that gets in our bilges.

One idea I'm kicking around is using penetrating epoxy and vacuum infusion. First, I would carve out all the damage, rebuild all those areas. Put the rudder in a bag and set up my vacuum pump to first suck out any remaining water. Then, set up a reservoir of penetrating epoxy to fill any voids with epoxy. I think this would give the existing rudder a new life for another 10-20 years. Finally, I would caulk the interface where the shaft meets the rudder to try to keep water out going forward.

Filling the revamped rudder with microballons and casting resin or epoxy (more $!) should alleviate any new water getting in. I suppose cutting solid wood chunks to fill spaces to use less epoxy is an option. Even just Fir 2x4/2x6 chunks in large spaces should seal in the epoxy and be fine I would think...?

[mcon12000]

Originally Posted by Spot

Might be worth talking to Foss Foam Products in FL and see if they make that one, could quote a custom, or could advise on the repair.

PS- "My plan is to use a hole saw to cut into the meat of the rudder to see what's inside."
I like this idea too.

If you read this send it to Foss Foam. Don’t DIY this its like any other boat project you’ll have plenty of associated items to deal with after removing it. Unless you have a machine shop the shaft work will have to be outsourced anyway. You’ll get a neutrally buoyant rudder back that will last another 20-30 years.

I would not be surprised if you find crevice corrosion in the shaft which will probably need to be replaced.

I’ve used Foss and they do excellent work.

[maine-cruiser]

Had a similar situation with my rudder, not as bad as this one. There was a crack oozing reddish water so I bit the bullet and dropped the rudder and took it home to check it out. Was concerned as well about interior welds. Consulted with Catalina support and also found a YouTube video of the factory making the rudder so had an idea of where the struts were. Interior of the rudder is high density polyurethane foam. Had to chop it out with a chisel, very dense. The shaft and struts and welds looked fine. Poured in a batch of 2 part foam and will cover the hole with biaxial glass and vinyl ester resin then gelcoat. Nice winter project! With any luck I've managed to attach a few pics.

Bill