Corrosion rudder stock. Do I need a new rudder?

[Viviane2000]

Bavaria 42 - 2001. After we suspected some corrosion on our rudder stock we dropped the rudder for further inspection. See pictures. The length of the corrosion is ~8mm with 4.5mm depth. Quite substantial.

I've contacted Jefa who makes replacement rudders, I'm not sure if they made the original rudder. They state any corrosion bigger and or deeper than 4mm means a new rudder. Corrosion smaller than 4mm can be fixed with a sleeve.

So according to Jefa it appears we need a new rudder. Since we're planning to go to the Pacific I tend to agree. Seems it's the only way to know for sure the rudder is sound.

- Anyone got experience with corrosion on the rudder stock?
- are there other solutions or is a new rudder the only solution?
- Is Jefa the only company making these rudders?

The cause of the corrosion is probably copper containing anti foul too close to the rudder stock.. We switched to Silic One 1,5 years ago, but the damage was probably already done. So please be careful with copper containing anti fouls!

[Yngmar]

With just that one pit, I'd take it to a welder. Also looks like the usual problem with JP3 rudders where the GRP isn't sealed to the stock and you probably have water in the rudder. Check for that and then you can decide if it's worth splitting (probably not, but it might make you feel better) or you just grind out the bevel and seal it as per the instructions on the Jefa site.

[Viviane2000]

Thanks Yngmar, with 88mm of solid aluminium there should be some wiggle room. But Jefa seems quite confident on their greater than 4mm putting = new rudder. But then again, they sell rudders..

After sailing 1,5 years including crossing the Atlantic I drilled a hole in the bottom of the rudder. Nothing. So the rudder should be dry on the inside. The sealing on the shaft / GRP definitely needs to be redone. If we keep this rudder..

[Viviane2000]

"The rudder stock can be "rescued" only if the pitting - each single pitting - is less than 4mm in depth and/or in width."
In that case a sleeve can be fitted. This means the rudder stock dia gets bigger so you'll also need new bearings and possibly new bearing house.

"Should the pitting be in some parts around 4mm in depth and/or in width or bigger, you need a new rudder, as it's not strong enough any longer. Then a new rudder is unavoidable!"

"No way – this rudder cannot be rescued, the pitting / corrosion is too serious and there is risk for breakage of the rudder under pressure."

"No, the rudder stock cannot be repaired/spot welded. The 4mm is due to strength parameters.

But most important is, that the corrosion/pitting will not only be visible outside / at the surface, but can follow / meander within the rudder stock itself."

For anyone interested I've included some snippets of my mail conversation with Jefa. They are quite confident in their 4mm corrosion maximum. Since they are they are the only experts with in depth rudder knowledge I've spoken to, I tend to agree with them. Mostly since we're planning to cross the Pacific.

Btw, Jefa is super helpful in their response and they have a rudder mold that is more or less the same as my existing rudder. So there's that.

[Yngmar]

A welder would have to clean it up before welding and then see if the pit goes deeper or not. I've taken things to a good welder that had been condemned by their manufacturer as "completely impossible to repair and cannot be welded! Must replace entire unit!" and the welder (although a highly skilled one, certified to work on nuclear reactors as I later found out) just laughed and had it sorted in 15 minutes and charged me a pittance.

Industrial welders regularly repair shafts that see much greater loads and/or spin at vastly higher rpm than a rudder where a slight distortion wouldn't even be noticeable.

The repair method Jefa suggests is a sleeve, which usually just means the pit gets filled with epoxy underneath. That indeed does not add any strength to the shaft, so they're right about their repair method's limitations.

But it's your rudder and your money

[Viviane2000]

If I was coastal sailing in the Carribbean or Med, I'd probably agree. Since we're going to cross the Pacific I don't want to take chances.

I'm not sure what aluminium the stock is made of. Could be AL6082 aluminium, in that case it's probably heat treated. The rudder stock would lose significant strength in the welded area. Correctly heat treating it again without removing the rudder blade is not possible imo. At that stage I'd rather spend the money on a new rudder. Moreover, I think my chances of finding a nuclear certified or similar welder on Curaçao are slim as well

Btw, I've contacted JP3 as well. This was their response: "We thank you for reaching out to JP3 about the repair of your boat. JP3 hasn't supplied Bavaria ever so we have no information about the steering system of your boat. Bavaria Customer Service will better assist and give you tips to repair or source a new rudder."

No response from Bavaria Yachts..

[Happysailor]

Well... I happen to know Curacao quite well and with regard to welding capacities you may get surprised.. they have Damen Shipyard and also previously a refinery.. you also need good (boiler)welders and machineshops in those places. Perhaps the shipyard or their partners can help you out for ND testing of the rudderstock and weld / flamespray / HVOF coating to beef it up again? https://www.damen.com/companies/shiprepair/damen-shiprepair-curacao  https://dickanddoof.com/
Always worth a try...

[Yngmar]

Btw, I've contacted JP3 as well. This was their response: "We thank you for reaching out to JP3 about the repair of your boat. JP3 hasn't supplied Bavaria ever

Odd! I wonder why their name is on so many old Bavaria steering parts then  

https://www.bavariayacht.org/forum/index.php?topic=3217.0

Corporate memory loss?