# Keel Bolts repair question??!!



## Petar (Nov 20, 2005)

Hi

I am looking into buying a nice boat but during survey i was discovered that seven out of nine keel bolts have rusted badly in the area where nuts were tightened on them. Both were stainless steel so no dissimilar material issue was there. I am not looking into the reason for corrosion but would like your opinion on local shop/engineer suggested method of repair. In essence they will first cut the bolts just below rusty area which will leave approximately 1 1/4" of bolt protruding from the keel. then they will be making 3/4"-10 UNC extension sleeve( it will have similar length as the original bolt height above keel) which will have inside thread to be threaded onto the keel bolts once the keel is put into position. Then they will put a compression sleeve around that sleeve and a washer on top then tighten all with a bolt on top which will be of certain length but not long enough to touch the old studs left in the keel. I am attaching few photographs. what do you think of this? Do ypu know of other method of keel bolts repair?

Keel bolts pictures by petarlolic - Photobucket

Regards/petar


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## Maine Sail (Jan 6, 2003)

Petar,

That is an option but if it were my keel, and I was going to this level, it would be on a pallet heading for Mars Keels in Canada. They actually physically replace the keel bolts with a special process.

*Mars Keel - Keel Bolt Replacement*


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## davidpm (Oct 22, 2007)

According to the Catalina 30 official repair recommendations they just use large stainless lag screws with a machine thread on the inside end.


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## roline (Apr 7, 2000)

Stainless is subject to crevice corrosion should it become in contact to stagnant sea water. The Na and Cl ions set up a corrosion battery in the stagnate water not allowing the stainless to oxidize to form a protective film. (Stagnate water results in the lack of O2 to allow oxidation) Monel, Bronze or if you need to consider stainless, Aqualoy 22 is less likely to pit. Best companies for keels is Mars and Foss for rudders. If the keel bolts are suspect, better check the rudder post in case there was a little galvanic corrosion going on.

Link to Mars:
MarsKeel - Technology


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## Maine Sail (Jan 6, 2003)

davidpm said:


> According to the Catalina 30 official repair recommendations they just use large stainless lag screws with a machine thread on the inside end.


David,

Lag screws are a band-aid at best and should be used along side other bolts that may have suffered some crevice corrosion. They should generally not entirely replace a cast in place J bolt unless this is a small boat. Lead keels are far to soft to be supported by just lag screws.

When I re-set the keel on my C-30 I spoke with three keel manufacturers and I was told by all three to absolutely not drill & tap or use lags in lead keels. I used the barrel bolt method but would not do it again as it leaked. If I need to do it again I would use the Mars method.

The op's keel has enough threads to use the sleeve method but personally I still much prefer new j-bolts cast in place..


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## zz4gta (Aug 15, 2007)

Anyone got a price estimate for 1000 lbs of lead heading to Canada? Sounds a bit pricey to me.


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## Petar (Nov 20, 2005)

Maine Sail said:


> David,
> 
> Lag screws are a band-aid at best and ONLY to be used along side other bolts that may have suffered some crevice corrosion. They should never replace a cast in place J bolt. Lead keels are far to soft to be supported by lag screws or just simple tapping directly into the lead.
> 
> ...


What are barrel bolts? How are they fitted?

regards/petar


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## Maine Sail (Jan 6, 2003)

Petar said:


> What are barrel bolts? How are they fitted?
> 
> regards/petar


Basically you drill and tap 2" diameter solid bronze round stock, cut about 2.5" long, to accept the 3/4" keel bolt. You then drill into the side of the keel to create a corresponding pocket for the bronze barrel nut to sit in.

Next a hole is drilled down into the barrel pocket from the top of the keel.

Please ignore my MS Paint skills, they suck.

Red circles are the drilled holes, gray is the barrel nut and red line coming into the holes is stainless or bronze keel bolts from above.

Once done you seal the whole thing up with epoxy and hope it does not leak. We actually tapped mine all the way from the top into the barrel hole so there was no slop but even after coating the keel bolts with epoxy and threading them in it still leaked..


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## ereiss (Nov 25, 2002)

Regarding hauling, you might try uship.com. No direct experience but haulers bid on your work and you can get references from them. Seemed like a good program when I was investigating moving a possible boat purchase from WI to MA. 

Just a thought.

Best wishes.


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## hellosailor (Apr 11, 2006)

"Once done you seal the whole thing up with epoxy and hope it does not leak."
What ever happened to tradition? You can indeed build a clay dam outside the hole in the keel, and then pour molten lead (with a bit of solder or flux to help it bind perhaps?) to seal the hole, instead of using plastics. If you preheat and do the pour right, the new metal will liquify into the existing keel metal and there'll be nothing to leak, just solid metal.


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## Maine Sail (Jan 6, 2003)

We were going to try that but the thinking was that the lead would cool too quickly and dam up prior to hitting the bottom of the bolt hole. It is COLD here in Maine and this was being done outdoors in the early spring late winter with cold keel temps so we decided against the lead. We did use a cold temp epoxy. 

If I had known about the Mars process at the time I would have shipped to them. We thought about pre-heating the bolts but in the end decided to tap and coat the threads with epoxy. It did not work out well, so in hind sight I should have melted some lead..

The only benefit to the barrel bolt is that you can always thread in a new keel bolt if it gets bad.


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## Petar (Nov 20, 2005)

So, short of shipping 2 Ton slab of lead from NW USA to East Canada for very expensive fix, i believe the fix i described in my original post seem to be most attractive solution. Looking at the sketch the engineer prepared (i am unable to scan and post it here) sleeves he is proposing to fit have 65% larger cross sectional area than original keel bolts hence 65% larger stress area. I guess I swill have to look at other solutions to see what else is available.

regards/petar


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## hellosailor (Apr 11, 2006)

Maine-
I would have thought a little tenting and one of those big ugly orange industrial heaters that looks and works a bit like a jet engine on a bad day, would have kept even the barnacles cozy and warm. I've always had reservations about epoxy bonding to lead, the oxide film seems to form so quickly that it sneaks it while you blink.

Petar-
I think the reservations some of us have about your engineer's solution, is that if you have stainless steel kell bolts, the traditional "J" bolts that go deep into the keel, even if you replace the top of them the lower section of the bolt is now likely to be suffering from crevice corrosion after all that neglect--and then the bolt can fail and let go within the keel, way below the top of it. So putting on barrel bolts and strengthening the "bolt" section up top, is NOT a structural repair to the bolt.
That's why the traditional repair is still to drill down into the keel, sink in new rod stock (bronze or stainless) and then either bend a "J" into the bottom of it, or add bolts on the bottom of it, working through transverse holes drilled or chewed into the keel. Complete new bolts are required in order to have faith in them.
The non-traditional repair would be to simply drop the keel, clean it and the hull surgically clean, and then literally GLUE the keel back on with 3M 5200 adhesive. Use the bolts to tighten it up until it cures, but once it cures--the 5200 alone will keep it attached and the bolts become a moot point. And even with your engineer's solution and keeping the old bolts? That's what i'd do for insurance. (Assurance.)

Mars Metal are THE go-to folks in this field, I would strongly suggest calling them to ask before you do anything. They can tell you about motor freight options (folks with motor freight accounts pay way less than strangers do) or perhaps dead-heading your keel back with a truck that is heading out your way. And certainly, they know how to attach a keel so it stays stuck on.

Some parts of a boat I'd screw around with, like how to mount the soap dispenser in the galley. But the keel....Nuh-uh, I want 110% reliability from that, with no questions, reserves, or doubts. And the folks at Mars are REAL nice folks to talk to.


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## mitiempo (Sep 19, 2008)

According to Dave Gerr lags would work as long as it is a low aspect keel. If the keel is higher aspect j bolts are the recommendation. Below is a portion of a letter from Dave Gerr published on Professional Boatbuilder issue 98 December/January 2006
If 5200 would hold a keel by itself why do manufacturers use bolts at all instead of 5200 and a few lags until it sets? I have never heard a qualified expert state that adhesive alone would ever work.


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## GaryHLucas (Mar 24, 2008)

After looking at your pictures I would consider another option. Cut off the keel bolts above the good threads. I'd buy a length of 1-1/4" Hex 316 Stainless bar stock, about $106, and have 9 Tee nuts made. They would have a internal thread to match the keel bolts, and one end turned round to go into the hole in the hull, leaving a hex nut at the top. Put a large washer under each hex nut to spread the load. I'd guess the machining cost would be another $200, but I think that would be competitive with all the other options.

Gary H. Lucas


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## Maine Sail (Jan 6, 2003)

mitiempo said:


> If 5200 would hold a keel by itself why do manufacturers use bolts at all instead of 5200 and a few lags until it sets? I have never heard a qualified expert state that adhesive alone would ever work.


My comments on lags were directly related to the keel in question and even Gerr suggests no lags in that scenario just as the three keel manufacturers I spoke with also did.

As for 5200 I can tell you that it will hold a keel on in the static position with keel nuts removed. Under sail the fiberglass would simply delaminate and the keel would part ways. When I was dropping my keel it held with nuts removed and we had to cut it off. Unfortunately if 5200 was as good as everyone thinks it is I would have never needed to re-set my keel in the first place.

When we had about 10 linear inches of 5200 left the keel ripped from the hull and dropped the 3/4" into its cradle. The 5200 held but the keel stub did not. 5200 can bond stronger to fiberglass than fiberglass does to itself.

That keel was re-bedded with Sikaflex and to this day is bone dry along the keel/hull joint. That keel was finally wrapped and the barrel bolt weeping stopped...


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## mitiempo (Sep 19, 2008)

Maine
I posted Dave's comments on keel attachment in full. He says lags only for a keel with an aspect ratio of .5 or less. That I think means a keel twice as wide at the attachment point as it is deep. I wasn't trying to suggest lags so much as put a qualified engineer's comments on this thread. 
I agree with your drawing of drilling through the keel side to side and using threaded rod with nuts on both ends. 
Merry Christmas


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## roline (Apr 7, 2000)

The barrel bolts that I think of are actually long nuts that will engage the exposed stud ends to allow additional threaded rod to continue upward. The lead would be removed around the exposed stud to allow maximum contact, at a minimum, greater than the diameter in contact length. The barrel bolt and new extension threaded rod would be sealed by pouring lead back into the area around the barrel, wicking locktite can be used to seal the threaded interface. Main issue is now the length of the barrel and its diameter in relationship with the holes on the hull. If the hull holes have to be enlarged, they will also need additional sized load washers to spread out the load to prevent stress risers for possible fatigue failure.....
The Cal 9.2 has side pockets for the bolts/threaded rod to pass into where nut/washer is used to secure it. This pocket is then filled with expanding foam and faired, or filled with highly filled epoxy...


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## Gary M (May 9, 2006)

I think your repair method described in the OP is just fine. It can be easily calculated by a mechanical engineer exactly how much load can be supported by the sleeve arrangement that you are contemplating. That and the addition of 5200 or my preference would be Marinetex and I think you would be fine. 
Of course it all depends on who is doing the calculations and does he know the original design loads. 

I looks like you have crevasse corrosion, not "rusting". I would suspect that there was a lot of salt water sloshing around in the keel sump for many years to cause that.

My 1984 boat had carbon steel nuts on SS rods. I removed the nuts and the SS was just fine. I took the keel off this summer to do some repairs to the glass. We put it back on with Marinetex and new SS nuts. It is much stronger than new.

Good Luck


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## NCC320 (Dec 23, 2008)

hellosailor said:


> Maine-
> 
> the bolt is now likely to be suffering from crevice corrosion after all that neglect--


How can one say "all that neglect". Exactly how do you neglect or not neglect something like this? The top of those bolts look fine, except for the one that was broken. So, inspection of the bolts wouldn't seem to show anything wrong until keel is dropped, which doesn't seem to be a normal preventative inspection.

Bilges are designed to collect water from various parts of the boat, and then the water is usually pumped overboard with a pump, but a small amount of water typically remains, covering the bolt heads/nuts. And typically keel bolts are exposed in the sump where water freely gets to them. What's wrong here?

Why does the corrosion on the bolts seem to be in the middle portion of the bolts, while the part next to the keel and the top end seem to be fine?


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## sailhog (Dec 11, 2006)

Mitiempo makes a very valid point, especially with repsect to the keels on Catalina 30s. It's my understanding that they are lead and lead-saturated brick, which would likely have very different structural properties than pure lead. With this in mind, it's probably why the people at Catalina suggest the lag screw approach -- because it works. And they would know.


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## Maine Sail (Jan 6, 2003)

Gary M said:


> That and the addition of 5200 or my preference would be Marinetex and I think you would be fine.
> 
> We put it back on with Marinetex and new SS nuts. It is much stronger than new.
> 
> Good Luck


There are a few ways to re-bed a keel and none of them, for me, would involve only a standard epoxy. Fin keels on older boats will move and flex some. They can be essentially a live joint unless you physically wrap the keel with lamination's of glass which many have done after re-sets. Epoxy it on and it will still move or flex some. A flexible epoxy in conjunction with a marine sealant will work better.

Unfortunately standard epoxy has minimal elongation before break so when it flexes it will fail considerably quicker than a flexible marine sealant. A product like a polyurethane can have a flexible range of 450% to 800% of the joint thickness thus allowing for movement/flex and the differing expansion contraction coefficients between the lead and the polyester/glass laminate. On a low aspect lead keel the flex is much more minimal and epoxy may be an okay choice but on a fin it is a likely short life before water gets to the keel bolts unless it was of the flexible type. Some manufacturers use special epoxies from the factory but even builders like Morris use a polyurethane sealant.

The best method I've seen where epoxy is involved is to mix an epoxy butter and then heavily wax the lead keel & bolts, or use mylar tape, or better yet grease the bolts. Drop the boat onto the keel and epoxy butter, let it cure lift boat off. Now you have a nicely matched hull to keel joint like a cylinder head to an engine block. You can also do it in reverse but I prefer the bond of epoxy to fiberglass as opposed to epoxy to lead for the epoxy butter mixture though either is probably fine as epoxy is tenacious.

Next you take a Dremel tool and cut a shallow v-groove into the top of the lead face of the keel that meets the hull. A laminate trimmer and edge guide with v-bit works better if the keel is wide enough for it to fit. Go all the way around the keel about 3/8 to 1/2" in from the outer edge until you complete a circle and the v-groove joins its self. Now apply a marine sealant, I like Sikaflex but 5200 is also good as is 4200, and drop the boat back down. The v-groove makes a nice thick gasket that can absorb lots more flexing than no thickness or minimal thickness. A 1/8" thick bead at the v-groove, of 5200, 4200 or Sika will stretch and move a LOT more than 1/64th of an inch of sealant before a failure. 600% of 1/8" is much more allowable movement than 800% of 1/64".

Most all builders do not take the time to make a "gasket groove" or to "butter match" the hull to the shape of the keel. It involves a lot more time than builders are willing to exert or spend time/$$ on.

For anyone's sake I would not advise solely the use of standard epoxy to bed a fin keel on a production boat. You may need some allowable movement as the forces on a fin keel are tremendous. I've yet to see very many that did not move some.

Any movement with standard epoxy will likely mean failure. Just because a fairing compound has cracked due to movement does not mean the marine sealant between the hull and keel has. All one needs to do is look at the raw number of boats in yards with fairing cracks along the keel/hull joint to see why using epoxy on an older hull as the sole sealant may lead to trouble. If the fairing cracks so then will the epoxy.

Here's a link to a good description, of "butter matching" the keel/hull joint, though they did not cut a sealant/gasket groove..

*Keel re-bed (LINK)*


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## mitiempo (Sep 19, 2008)

I agree with Maine. A perfect hull/keel interface is important but you also need enough sealant to handle the movement. 

sailhog
Lead saturated brick? A fellow named Antoni on the Catalina 30 group just dropped his keel and replaced all the bolts the proper way. He also reglassed the inside of the stub for added strength. He cut into the keel to remove the bolts and replaced them with threaded ss rod and nuts. The bilge was contoured so the nuts are on raised sections and won't end up sitting in water. He used epoxy and G10 for the stub rebuild. It was a big job and he did a proper job. His boat was an 80's model. The keel was lead. No bricks were evident.


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## sailhog (Dec 11, 2006)

Brian,
I may be a bit misinformed on precisely how the keel on the C30 is constructed, but I've read this in a couple of different posts. Below is a post from Max Munger, the tech editor for Catalina owners group forum. This is the only post I could find with regard to the brick in the keel. Read the last line:

And with all due respect I can say as technical editor and owner for 26 years, no C30 has ever lost its keel by falling off. The wood was added back when boats were "overbuilt". yes the wood was a bad idea, but thousands of C30s are still out there with no bilge problems. it all depends on the PO care and maintenance and operation.
The bolts and washers do not sink into the bilge. They don;t even move! Only if the owner keeps tightening down the nuts, against all of our advice, will any depression form.
I see you have not perused the web site as yet. The Catalina "fix" is online there. We are well aware of it. If you look at the Catalina fix, it only calls for a couple layers of glass to reform and smooth the removed bilge area. It is NOT adding back any strength to the keel area. 
The keel is 'glued" on at the factory and the keelbolts only align it during curing and movement around the shop. removing a keel usually involves a chain saw to cut the seam! The keel will not flex or bend due to loose keelbolts from the rotting wood.
The smile is caused by "banana-ing" the boat on shore by improper blocking.

Did you know the lead keel is also filled with bricks?


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## GaryHLucas (Mar 24, 2008)

NCC320 said:


> Why does the corrosion on the bolts seem to be in the middle portion of the bolts, while the part next to the keel and the top end seem to be fine?


I beleive that stress also is a factor in crevice corrosion. So the top of the bolt and the portion below the nut don't see the stress of the nut itself against the stud.

Gary H. Lucas


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## roline (Apr 7, 2000)

I found an article on crevice corrosion:
Crevice Corrosion

The issue is lack of O2 in the water to allow for the formation of a passivation layer to protect the underlying metal. Stagnant seawater is responsible for this condition. SO stainless 304 keel bolts in a pocket of seawater that seeps between the keel and hull or down from the bilge and is stagnant is a perfect candidate for crevice corrosion.
When I was working on steering gears we were very concerned on the possibility of Cl contamination due to corrosion effects....


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## NICHOLSON58 (Feb 22, 2009)

Whatever method you choose I suggest 316L stainless. The crevice corrosion discussion was spot on and can even occur in fresh water. 316L is less vulnerable. Seal the heck out it when you are done.


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## hellosailor (Apr 11, 2006)

"Did you know the lead keel is also filled with bricks?"
That couldn't be literal...if you dropped "clay" bricks into molten lead, they'd just float up on top of it. So...beyond asking why, how?

" Only if the owner keeps tightening down the nuts, against all of our advice, will any depression form. ... literally glued on..." That would appear to be part of Arthur Clarke's famous statement, that any sufficiently advanced technology will appear to be magic. I can torque down a 1/4x20 carriage bolt hard enough to pull it through a 2x4, but a 2x4 is strong enough to build houses with. And, more than one boater has found that if their keel was "caulked" with 5200 or a similar product, unbolting it won't matter. Heck, there are aircraft wings "glued" on these days.
An eager beaver with a wrench and no torque specs for it...that's all too common.

But convincing bricks to sink in lead? _Now that's magic._


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## mitiempo (Sep 19, 2008)

The good news is Boeing does not use 5200.


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## Maine Sail (Jan 6, 2003)

hellosailor said:


> And, more than one boater has found that if their keel was "caulked" with 5200 or a similar product, unbolting it won't matter. Heck, there are aircraft wings "glued" on these days.


Surely you are not suggesting that 5200 can hold a keel on for very long while actually sailing??? I have seen first hand that a keel will stick there in the slings withe the nuts removed. But I have also seen it tear a HUGE chunk of a keel stub off when it finally let go.

If Max was right, that the keel bolts are only there for alignment at the factory, then there would only need to be two bolts for alignment, one at the front and one at the back of the keel, and they could simply be tapped into place and be 3/8" instead of 3/4"-1"...

If the assertion is true that the 5200 is what is holding them on why do manufacturers spend huge money on multiple large diameter 316SS bolt stock and then cast them into the keel as j-bolts..? It seems they could save lots of money by simply using two 3/8" keel bolts one at the front and one at the rear...?

I'm sure many of these folks are glad they have bolts as their sealant is surely beginning to fail:

































This guys keel ripped off even with bolts and bedding:









Oh and like anything 5200 still requires proper prep. This keel dropped right off once the nuts were removed and the hull lifted. The keel was just as it came of the hull and all the 5200 was still on the boat.. Despite a lot of crevice corrosion I am fairly certain this guy is glad he had keel bolts.. 









A failure of the sealant, not the bolt, is what cause this crevice corrosion...









So who's going to be the first to remove their nuts and prove Max's theory..?


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