Both rudders toast after less than 8 years!

[lauriek]

SO349 rudders stocks are not in the water when the boats is moored, so it is surprising that both my rudders stocks are so badly affected by crevice corrosion - I think related to an annular groove around the stock at the top of the rudder, enclosed by the thrust bearing which sits on top of it.

The linked video goes public on Thursday - to give Jeanneau time to comment before it is public.

[Zanshin]

Crevice corrosion has several potential causes, only some of which pertain to the metals Jeanneau uses.

Years ago, I bought a used 4-year old Jeanneau 43DS. Shortly after buying the boat and sailing around, my rudder snapped off at sea. Both the conscientious surveyor and myself missed the crevice corrosion that caused this. It turns out that the marina where it was kept was very electrically active and this triggered and exacerbated the corrosion.

Therefore it is important to realize that corrosion (once we can see what's in the video) is not necessarily the manufacturer's fault or doing, there is always more to the story.

[Trevor]

Hello lauriek,

That is indeed an unfortunate position to be in. I echo Zanshin's comments that sometimes things are not necessarilly how they seem.

Within this forum we have heard of a Jeanneau losing a rudder that was caused by electrolysis, the corrosion caused by leakage current from the binnicle light conducting throught the steering gear and entering the water throught the top of the rudder stock. This caused the rudder stock to reduce in size until it ultimately snapped off. The return path is through the propshaft back to the motor (negative of the battery).

This form of corrosion is aggressive and unlike galvanic corrosion has the power of the house batteries to accelerate the damage.

I know the corrosion mechanism has been quoted as "Crevice Corrosion". I am curious how that corrosion mechanism has been identified as the cause. I guess seeing the video when available may answer some questios.

Regards,

Trevor

[MalcolmP]

My sympathies for this occurrence. Hopefully you will be able to get new rudders and be back sailing again soon.

The article that Trevor mentioned regarding the stray current from a compass light on a Sun Odyssey 45 is written up here:


www.jeanneau-owners.com/hintsandtips/so45rudderloss.html

Please keep the forum updated on how this progresses and Jeanneau's response.

Good luck. Malcolm