Small crack on rudder and rust on keel

[Renaissance]

We had our haul-out and the boat-yard came back with a couple of issues: A small crack on the port side of the rudder post and some corrosion at keel bottom, leading edge and trailing edge. I am attaching some photos for reference (sorry for the large sizes, couldn't see to make the linked images smaller)

This is our first haul-out after purchase. We will have the boat yard fix these but wondering how common these are, how worried we should be about them and what other inspections and remediations may be required based on these findings.

Also the crack on the rudder is a mystery to me. We never hit anything major (maybe some small wood pieces at low speeds) never had a grounding etc. Also struggle to envision the type of impact would make a crack like that.

Thoughts welcome.




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[Zanshin]

I think that the rust on the bottom of the keel is not an issue. Any light grounding, even in mud, can remove the bottom paint and also the barrier coat, leaving the keel iron exposed to sea water.

But the rudder might be something different. I had a 43DS where I lost my rudder - it snapped off right where your picture is, where the iron stock meets the rudder. This was not a good experience, as I was at sea at the time...

The cause was crevice corrosion, which had weakened the metal stock. While this looks a bit different, I am wondering if the crack is due to corrosion on the inside of the rudder which expanded and the resultant pressure cracked the rudder outwards.

Can you show the picture to your pre-purchase surveyor? He/She might offer an opinion and perhaps your survey has a picture of this location and you can confirm that it wasn't there a year ago.

[Don Reaves]

I agree with Zanshin's comments. Regarding the rust on the leading and trailing edges of the keel, this seems typical for iron keels. Best to fix them when they are small, as they will only get worse. On my SO35, I made a half-hearted attempt at addressing small rust spots, only to have them finally get away from me. I had the yard sand-blast the keel down to bare metal and then carefully apply a new barrier coat and antifouling. It's been 7 years, and the keel still looks good. So while it was quite expensive, it was the right thing to do.

[Renaissance]

Thank you both. We have a SO 43DS too. This didn’t come up
In the pre-purchase survey. Unfortunately I don’t have a photo of that exact spot from the survey. But we had explicitly asked the surveyer to check the rudder and rudder post but he didn’t come up with anything.

Zanshin, how did your problem manifest itself? Do you have any photos? We are thinking of cruising to Alaska in a couple of months, so if this is serious, it could be a big deal.

[reiner]

 We found  a very similar crack in the same area of the rudder, also a SO 43DS shoal draft during ghe survey, before 
buying our boat.
The surveyor assumed that it is only the gelcoat and not a big problem because he found no delamination.    
It was later grinded and filled by the boatyard.
No new problem the last 5 years.  

[Zanshin]

Renaissance - the problem manifested itself with a sudden looseness in steering and a rounding up that I couldn't correct. When I looked behind me the rudder was floating away from the boat...

It was an ex-charter boat and was kept in an electrically very active marina. The rounded edges in the pictures below hint that this had been going on for a while. While I think my problem was different from what you are seeing, it is worth thinking about. If the boat is still out of the water then a rubber mallet sound test might give you a clue as to whether this is just gelcoat or a symptom of a bigger problem.

[manaia]

We get the rust patches fixed each time the boat is hauled out to do the anti fouling, I have assumed because it’s cast iron it’s just something that it does.

I believe that part of the rudder is pure gel coat and so a crack here is not structural - there was some pics on the internet a while ago of a yard in Greece who regularly repaired Jeanneau rudders and it appears to be a common issue.