Cast iron keel problem! Advise needed

[timot]

Hello All,

I really need your advices or suggestions from experts...

Last year in May 2022, I bought a Dufour Gib Sea 33 from 2000 and during the survey, the surveyor just noticed that my boat needs to be sanded till gelcoat and do the antifouling from scratch. (Previous owner did the antifouling by himself and did it very badly...)

Yesterday I took the boat off to do antifouling, and while observing the keel, I saw a crack and with little force the part just came to my hand. (Please see the photos..)

I am now truly worried if this is a big problem or not. For now, the paint company did only one layer antifouling and covered the broken part with epoxy. Asking me to come in October after the summer and fix things properly. I am also attaching the photos of fix...

I am not sure what to do now, according to people in the yard the boat has an electrolysis problem and it resulted in this and advicing me to do a check when the boat is again in the water. And I dont know what to do, my biggest horror is that the keel goes off one day while sailing....

Could you please have a look at the photos and advice what to do! Thanks from now...

I also add photos from the bilge, there are 11 stainless steel screews holding it, the setup: 1-4-4-1-1

[neilpride]

If the entire upper part that join to the hull is in the same condition, I think you need a new keel.

[timot]

Originally Posted by neilpride

If the entire upper part that join to the hull is in the same condition, I think you need a new keel.

Do you know there is a way to check it? I will ask for a surveyor to look at it.

[neilpride]

Get a chisel, hit the joint, until you see healthy iron, another idea can be ultrasonic testing.

[RaymondR]

First thing to do is clean it off and dye check it to see if it has other cracks.

[bil56]

poor quality cast iron + probably corrosion + possibly shock (check the bottoms), it's worrying ...

[neilpride]

Jezz, pic number 3, is that a bolt sticking out?

You definitely have to lower the keel, sorry to be pessimistic, but if that is the bolt you see, you're screwed.

[neilpride]

If I were in your place, I would call Mars Keels, send them the photos and they will advise you or give you a quote.

[MicHughV]

Have to echo neilpride's view...that 3rd pic shows the keel bolt in plain sight.....and that's what you see....no telling what you can't see elsewhere...

Also note the rust under the keel bolt washers....another "sign" of potential problems elsewhere

I wouldn't sail this boat anywhere....seriously....

Don't second guess the situation....have the keel dropped for a closer look...it's a bummer.....but the keel issue needs to addressed.

[boatpoker]

I feel for you, i just went through a 4 month $60k horror story myself.
Take Neils suggestion and call the keel manufacturer tho' I don't think it's Mars as I've been through their plant and they don't do iron castings.

Also don't take advice from anyone who uses the word "electrolysis". Electrolysis is an induced process found in industry and laboratories in which the anode is positive and the cathode is negative whereas on your boat it’s the anode that is negative and the cathode which is positive … it simply cannot occur on a boat.

[hugosalt]

Yes, keel bolt in pic 3 and threads on piece in pic 4.

[wyb2]

I got to think that started with a casting flaw, maybe with a grounding break the camel’s back (location is right). It’s iron, corrosion comes with lots and lots of classic red/orange rust, on the order of 10x the volume of the iron it replaces. I don’t see any of that.

But yeah, just sailing on would be insane. Drop the keel and get a good look at everything.

Edit: what on earth is going on in photo 2? Something sticking out the top of the keel bulb?

[Marathon1150]

Beneteau uses iron keel bolts in their iron keels to avoid galvanic corrosion. We had to replace 4 of the 10 keel bolts on our Beneteau Idylle when the bilge was flooded for a couple of months while we were off the boat and our boat checker didn't check the bilge The tops of the corroded bolts were easily broken off by hand. We used stainless replacement bolts coated with epoxy to minimize the risk of galvanic corrosion occuring between the iron keel and the new bolts. That was 6 years ago and all is well.

I bring this up because if Dufour uses the same construction techniques as Beneteau, the bolts should be iron, not stainless. Its possible that the keel has been previously removed, possibly for repair, after a grounding.

Our second boat, also a Beneteau, has this precise condition. During a pre-purchase inspection I noted that the keel bolts were stainless and the PO said "yes the original bolts were showing some rust so they were replaced". What he did not mention was that the keel was off because of a grounding and the boatyard replaced all of the iron bolts with stainless when they reinstalled it. I learned this from the boat yard that did the work.

Dufour's are well known for high quality. It is possible that the keel has a casting flaw but it seems more likely to me that it was damaged and then repaired. Other Dufour owners might be able to help with this question. In any case, as others have noted, it would not be prudent to sail the boat in its current condition unless the yard that did your new but temporary paint/epoxy job are super confident that the rest of the keel is ok.

[double u]

Originally Posted by boatpoker

I feel for you, i just went through a 4 month $60k horror story myself.
...Also don't take advice from anyone who uses the word "electrolysis". … it simply cannot occur on a boat.

easy there!
While "electrolysis" of course is used falsly (the problem usually is "galvanic corrosion"), "electrolytic corrosion " (which is meant by "electrolysis) does exist:
https://www.belmontmetals.com/galvan...h-zinc-anodes/

[Don C L]

I'd want to see the rest of the keel too, but that also looks like it may have been damage from a grounding. The aft part of the keel gets thrust up and given there is not much iron there around that bolt, I can imagine it just snapped off the iron around that one bolt. The rest of the keel may be ok. Hope so!

Welcome aboard BTW!