Terrifying Keel Bolts !!

[wyb2]

Originally Posted by MicHughV

look at minute 4:06 thru' 4:10....you can see the inserts clear as daylight...

The hexagon depressions? I suppose that could be some sort of insert. Could also be a locating feature for the drill/tap operation.

[fourlyons]

Why would you use a thread insert in a steel fin, lead maybe, but not steel?

[Icarus]

Originally Posted by Papawads

We have 3 rows of 2 huge bolts holding the keel on, to our 2001 Jeanneau SO 43 DS, each row with a metal plate and nuts above.



The centre row have corroded to the point that the nuts are disintegrating, edges literally falling away. The others seem OK.



Questions:



1. Are these iron, not steel? Or maybe cheap steel not 306/316 SS? If so WHY????



2. Assuming this is a job to replace the nuts, should I renew the plate too. Its also rusty. Do you think the threaded bar, coming up through the hull, is changeable also? Can we use 316 SS?



3. Presumably I need the boat hauled out and sat on the keel when thus is done? Or being the centre ones, could this be done afloat?



This is mildly terrifying us, so any help greatly appreciated.



Thanks

Papawads

Clean the nuts and if there is enough metal left unscrew it with a socket and breaker bar. By the looks of it they are ready to fall of already.
Inspect the thread, new wahers and nuts and torque them..120N or so.
Why they don't use galvanised carbon steel keel bolt god only knows.
If it was my boat I would I certainly would lift the boat off the keel for piece if mind.
If the bolts are SS there is a danger of crevice corrosion which is hidden where the bolts go through the hull.
If the ballast keel is cast iron the bolts are most likely screwed in and not cast in.
I removed a number of keels on Beneteaus and they used gal bolts...screwed into the ballast
Judging from your lack of engineering knowledge it would be best to get a shipwright to do the work, just to be on the safe side.

[Icarus]

Originally Posted by neilpride

You can do better and without worries in the hard, better to retrofit with 316 ss plates, probably the bolts are ok, something you are going to see when the nuts and washers plates are gone, clean well the bolts and see if they are still solid, easy job..

Btw, ask Jeaneau for torquing specs.

Probably ok ?
How would you know unless they can be extracted and checked or replaced?

[neilpride]

Probably ok, I'm not saying that they are 100% ok, good to see if there is rust streaks coming from the hull keel joint, if not, they are probably ok , looking at the photos what i see is a very common problem on these french boats, and very easy to fix if you are a bit handy, the plates and nuts look bad, the steel looks horrible once it starts to corrode, but even I would dare to say that once those nuts are free of visible corrosion they may even have material to hold a little more, or not.
What I see in the photos is that the bolts don't look any worse than many beneteaus or jeaneaus sailing out there.

[neilpride]

One more issue to consider with these flat bottom fin keel boats, the massive structural grid liners are hollow, any leak tend to found this way by the limber holes to the small mickey mouse bilge sump, and some amounts of water tend to rest inside on the molded liner, leaving you with a wet bilge 24/7.

My advice to the OP after this rust keel bolts episode? try to found all the leaks , fresh water or salt water , link the shower sump to a pump who discharge to the grey water tank, prop shaft dripless packing glands are superb, fridge , etc.. leave the flat bilge bays dry as much as possible , my 2 cents.

[Pete7]

Originally Posted by neilpride

leave the flat bilge bays dry as much as possible , my 2 cents.

Indeed, makes the boat much drier and reduces the smell.

Its bilge keeled so no centre keel studs. Down side is the water tank has to come out to reach the starboard studs.

Pete

[MicHughV]

You guys tear me up...watch the rest of the video and you can see the keel bolts being screwed into the keel threaded inserts. The guy doing the job, covers the inserted part of the bolt with locktite and screws it into the keel. Clear as daylight. Minute 5:12 onwards. The threaded part of the keel bolt appears to be around 6" embedded lenght.

I'm not sure how the threaded inserts are cast into the steel keel, but I suspect that they are likely part of a cage, whereby all the inserts are welded to a cage of sorts to keep them all aligned correctly. The cage then gets dropped into the keel mold and the steel poured. It is just a guess on my part based on how I would approach the job. The small embedded lenght of the keel bolt would suggest that the "cage" extends down into the keel.
Locktite comes in various strength forms...from you'll never remove this to you might remove it.

[MicHughV]

As an aside. My Beneteau does not have a bilge pump per se. It has a hose in the shoebox sized cavity in the keel that pretends to be a bilge that is connected to a pump under the starboard side settee. It has another hose with a strainer connected to the manual pump in the cockpit.
That's all the size available in that "bilge cavity"

It is not a good setup. With that flat bottom, water that finds it's way into the boat ends up on the low side of the boat when heeled over, and not the bilge cavity. While there is an automatic bilge pump switch, it is located on the hull, as there is no space in the bilge cavity. You'll have quite some water in the boat, before the switch activates.

The hull is only about 9" or so below the floorboards.
It requires diligence to lift the floorboards to check for water in the bilge. It's a pain in the butt, but if you want to keep the bilge dry, as you should, this must be done.

[Pete7]

Originally Posted by MicHughV

I'm not sure how the threaded inserts are cast into the steel keel, but I suspect that they are likely part of a cage, whereby all the inserts are welded to a cage of sorts to keep them all aligned correctly.

If its a helicoil then an oversized hole is drilled and special tap used to create a thread which the helicoil then screws into. Reversing the direction snaps off a little bar across the helicoil after it grips the hole. There is an bit of thread visible which perhaps shows the end of the helicoil at 4.12m. However, this doesn't mean its original and could have been added if the threads were in poor condition.

Pete

[MicHughV]

I suppose that's an option, but I would think it would be easier and less expensive to cast something into the keel, rather than drill it out later.

I've been involved with construction projects where rebar was inserted into cast concrete with inserts, not often seen or done.

Nonetheless, the video does provide a clue as to how the keel bolts are attached to the keel.

[skipperpete]

Originally Posted by MicHughV

I suppose that's an option, but I would think it would be easier and less expensive to cast something into the keel, rather than drill it out later.

I've been involved with construction projects where rebar was inserted into cast concrete with inserts, not often seen or done.

Nonetheless, the video does provide a clue as to how the keel bolts are attached to the keel.

Yes indeed, those holes have thread inserts, just watched the Vid on a wide screen TV. Any guy that shows up to a job with just two big adjustable wrenches and a less than speedy approach when using anaerobic adhesives needs to lift his game, why did he slightly unscrew the stud when he released and removed the locking nuts. I use thread inserts of several types on cast iron engine blocks when head bolts strip but then fit a stud rather than a bolt.
Thanks for the video, all good info.