Keel Bolts repair question??!!

[Petar]

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

[Maine Sail]

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

[davidpm]

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

[roline]

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

[Maine Sail]

Originally Posted by davidpm

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..

[zz4gta]

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

[Petar]

Originally Posted by Maine Sail

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.

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.

If lags were strong enough factories would use them as it is far easier to set the hull on a keel with no bolts, then drill into it vs. templating each hull/keel and setting the hull carefully over the bolts.

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

What are barrel bolts? How are they fitted?

regards/petar

[Maine Sail]

Originally Posted by Petar

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..

[ereiss]

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.

[hellosailor]

"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.