Beneteau First 405 keel bolts replacement

Discussion in 'Sailboats' started by bigkahuna, Mar 30, 2013.

  1. bigkahuna
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    bigkahuna Junior Member

    I'm looking at a 1987 Beneteau First 405 that looks to have some of the typical issues of the Beneteaus of that vintage. One area that concerns me most are the keel bolts. The keel on Beneteaus of that vintage are cast iron and galvanized, high tensile steel bolts were used to secure it to the floor of the boat. The keel bolts on this boat are pretty badly rusted, and the very aft most bolt appears to be directly under the Perkins diesel engine. I've already done a bit of homework on the subject but after talking to the local Beneteau dealer I've gotten some conflicting opinions on how to handle the issues.

    The advice I found on the internet recommends I clean up the rusty bolts and replace them one by one with galvanized, high tensile steel replacements available through Beneteau USA.

    The local Beneteau dealer said what they do now is to drill new holes (though the floor and into the cast iron keel) and install new stainless steel bolts.

    I'm not sure I like that idea for several reasons:

    1 - I fear the use of dissimilar metals (cast iron + stainless steel) will cause bigger headaches down the road.

    2 - Stainless is weaker than high tensile galvanized (what the original bolts were made of).

    3 - When it comes time to sell the boat it's surely to get the scrutiny of the marine surveyor.

    Opinions anyone?

    The real sticky issue will likely be that keel bolt that is directly under the engine. There's maybe 4 - 6 inches of clearance under the engine so it will be darn near impossible to pull the old bold out without first lifting the engine. I wasn't really able to see the condition of that bolt on my last visit, but when I poked my fingers in the hole it felt like it was in really bad shape.

    Anyone else have a F405 and have any ideas how to handle this?
  2. sean9c
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    sean9c Senior Member

    I don't know anything about Beneteau keel bolts but I'm curious. Are they studs cast in the keel or bolts threaded down into the keel? If Beneteau has a recommended repair I'd do that. You might want to contact Beneteau rather than a dealer for the correct advise. If not I'd use galvanized and keep the bilges dry.
    Just move the engine to get to the last bolt, it isn't all that heavy.
  3. michael pierzga
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    michael pierzga Senior Member

    Nothing wrong with galvanized keel bolts. What is the problem ? Have they lost mass at the keel hull joint ? or are they simply corroded in the bilge ?

    Is the keel leaking ?

    Has the keel been removed from the boat ?

    Has corrosion formed in the keel hull joint ?

    Replacing keel bolts in a cast keel is major it necessary. Has the boat been surveyed.
  4. gonzo
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    gonzo Senior Member

    If the rust is only on the surface, it should not be a problem. Replacing them is an expensive job, and unless it is done properly will make things worse. To do it right when you change the bolts, you will need to separate the keel for re-bedding.
  5. PAR
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    PAR Yacht Designer/Builder

    What Beneteau has likely found is it's cheaper to pay for the labor to drill and install new bolts, then the labor to remove the old ones (if they can), chase the threads, possibly drill them out and install coils, then install new bolts.

    In a perfect world, the bolt should have been replaced by now, but if left too long, you'll probably get half out, while breaking the other 50%. You can try to remove the broken bolts, but this too can leave you with broken extractors in the holes. So, just drilling and tapping for new bolts makes a fair bit of sense, as the cost effective way to get back in the wet stuff.

    If the keel is currently tight, you can just drill and install the new bolts. If the keel is leaking (probably), then you have no choice but to drop it, clean up the faying surfaces and while you're there torque out the old bolts.

    If it was me, I'd make a good try at backing off the old ones. You can usually tell by looking if they'll come out, though only torque will tell. If they come out, you're in luck, if not, you know what you have to do.
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    BATAAN Senior Member

    At a yard I spent many years working in, our standard keel bolt test was to mark a line across the top of bolt and nut, then try to tighten the nut. Usually it tightened slightly and we could see how much from the marked line. Sometimes it refused to move (3/4" drive with a long bar) or broke off, showing the condition of the bolt. Many times we dropped ballast keels, made new "Aquamet" SS bolts, re-bedded the faying surfaces and re-bolted the whole thing. Not an easy job, but not too hard either. When machining the tough SS threads we used Coca Cola as a cutting fluid and it worked great.
  7. bigkahuna
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    bigkahuna Junior Member

    I'll try to provide some additional info:

    - The bolts are threaded into the top of the cast iron keel. So what you see in the bilge are the heads of bolts and washers. I'm told (by other Beneteau owners) that the bolts do not penetrate the keel very far, roughly 3" or less.

    - I don't see any weeping of the bolts nor leaking of the keel.

    - I don't own the boat yet so won't know how bad the corrosion of the bolts are as I cannot do anything more than a visual inspection. From what I see, though, it's worse than just surface rusting and the washers are almost completely gone.

    I got a couple replies from other Beneteau owners on a different forum and they all indicated that they were able to extract and replace the bolts. I plan on giving Beneteau USA (the US distributor) a call tomorrow to see what they have to say.
  8. PAR
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    PAR Yacht Designer/Builder

    Bolts (given proper tools and techniques) are fairly easy to extract from a bore. If the washers are eaten up, the exposed "neck" of the bolt at the interface, will also be fair chewed up, but again, you can drill them and extract them if necessary. The bolts don't have to "penetrate" very far to be effective.
  9. keith66
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    keith66 Senior Member

    Similar problem different boat, I own a Sabre 27, built in 1971, she has a bolt on cast iron keel that was bolted on with 7 one inch whitworth studs tapped into the keel. After 30 years afloat the frd most one had started to leak so i dropped the keel to reseal it.
    Apart from the leaking one the bolts were as shiny as the day they went in.
    No galvanising just plain HT steel, the nuts had been glassed over on the inside & the lack of oxygen had prevented corrosion. Interestingly the yard had bedded the keel on wet csm before bolting it up, no mastic whatsoever.
    Not something i would normally regard as good practice but it had guaranteed a perfect fit that had lasted 40 years.
    In the end all but the frd bolts were re used.
  10. bigkahuna
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    bigkahuna Junior Member

    Spoke with a tech at Beneteau USA this morning and he pretty much agreed with what the other Beneteau owners have been telling me.
  11. DGreenwood
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    DGreenwood Senior Member

    All this advice is good and I could probably throw more at you but I get the impression what you are really after here is a sort of affirmation that your bolts will be OK.
    This is my philosophy on keel bolts: If I am not 100% sure about them, then any amount of labor or investment is worth it to make myself comfortable about them. It is like wondering if the wing is going to stay on your airplane. You do not want to ever be in a position to ask yourself that question. Considering you are already asking yourself this , you should only buy the boat with the notion that you are going to take the keel off and do whatever it takes to make yourself absolutely confident.
  12. bigkahuna
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    bigkahuna Junior Member

    No, not at all, and I apologize if you misunderstood my original post. The keel bolts need to be replaced on this boat, no argument. But what I wanted (and got) were opinions on how best to achieve this.

    Thanks to everyone who replied. :)
  13. powerabout
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    powerabout Senior Member

    in the old days they used manganese ( or others) bronze studs
    you could remove them to inspect or replace them.
    I think Stormvogel still has its originals in it

  14. jamieh3
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    jamieh3 New Member

    If you put in Stainless keel Bolts (which is a good idea) be careful of the grade as 316 won't be good enough, might need to get Duplex bolts machined to order:

    And you will need to keep dissimilar metals isolated to prevent Galvanic Corrosion:

    Tef Gel does a good job of this - you should be able to find some locally where ever you are:
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