Keel bolt replacement / 3M 5200 strength

[Rol1964]

I was considering keel bolt replacement (one at a time) on my new to me 1974 P26. Previous owner did a full keel re-bed approx 12 years ago. He told me that he used “liberal” amounts of 5200 on the full bolt / bore, as well as the keel to hull joint. I’m a newb. This is my first sailboat. I’m questioning the merits of even bothering with this task. The exposed bolt end and nuts are significantly corroded. Is the 5200 too strong to consider driving the bolts back down through?

[tkeithlu]

It sounds like this job is going to open Pandora's box. Consider cleaning the nuts, and perhaps loosening them one at a time to see that the threads are OK and you can re-torque them.

[slug]

Originally Posted by Rol1964

I was considering keel bolt replacement (one at a time) on my new to me 1974 P26. Previous owner did a full keel re-bed approx 12 years ago. He told me that he used “liberal” amounts of 5200 on the full bolt / bore, as well as the keel to hull joint. I’m a newb. This is my first sailboat. I’m questioning the merits of even bothering with this task. The exposed bolt end and nuts are significantly corroded. Is the 5200 too strong to consider driving the bolts back down through?

5200 was a bad choice . 5200 is a structural adhesive . It incorrect engineering to bond the keel to the skin of the boat

In future use a bedding compound such as 3m 4200

Since the bolts surface area is small you should be able to overpower the 5200 bond

[psk125]

Is the keel falling off? If the PO coated the bores, bolts & nuts w/5200 and put them back in twelve years ago, they should be good for a good while unless you plan on running into some rocks at 10 knots. Putting time/money/effort/worry into the keel of a 1974 boat is a bad ROI. Unless it has apparent problems, tkeithlu is right - avoid Pandora’s box. Slug is right also: if you hit rocks and need to rebed the keel, 5200 is not the thing to use. If it ain’t broke, don’t fix it. In the meantime, leave it alone and go sailing.

[LakeSuperior]

This is pretty obvious but if the nuts are corroded and if you use your energy remove the nuts to inspect the threads at least replace the old nuts with new nuts.

[Rol1964]

As much as part of me would enjoy the challenge, consensus seems to be leave it alone. I will likely just paint the hull and revisit this at a later time if or when necessary. Thanks for the suggestions.

[tml]

Our lead keel was built with 5200 between the keel and the glass " stub". After 14 years and at least 30,000 offshore miles when short hauled it was weeping at the joint. Tried tightening bolts etc but ended up dropping the keel. After removing the nuts and cutting the covering glass the travel lift picked the boat up and we watched waiting for the keel to separate. We waited a long time and it never moved. 11,600 pounds of lead with encouragement from wedges, sledge hammers etc would not drop. Finally the seam was cut with a saws-all and separated the joint.
5200 is not always appropriate but it is very strong and a keel joint seem a pretty good place to use it.
Tom

[glcalahan]

Never use 5200 on anything that might need to come apart in the future....ever. The silicone bronze rudder gudgeon on my '72 Pearson 33 was put on with 5200. I used DeBond, Map, butylene gases, improvised pullers and 3 months trying to remove and failed.


I hope someone can give you positive suggestions regarding your keel but 5200 has no place on a boat. What is worse....I have used it often. Lessons learned....

[Boatwright]

Originally Posted by glcalahan

Never use 5200 on anything that might need to come apart in the future....ever. The silicone bronze rudder gudgeon on my '72 Pearson 33 was put on with 5200. I used DeBond, Map, butylene gases, improvised pullers and 3 months trying to remove and failed.


I hope someone can give you positive suggestions regarding your keel but 5200 has no place on a boat. What is worse....I have used it often. Lessons learned....

Actually... After many sad outcomes trying to improve the durability of mahogany runabouts (Chris Crafts) by painting epoxy resin on the wood that resulted in trapped moisture and rapid rotting, they accepted best method is to bond double-planked bottoms in 5200.

It is tenacious stuff. I'd leave your keel bolts alone. BTW are they steel, galv. steel, or stainless? Corrosion scenarios for all are different. Any chance you have stray current or galvanic corrosion issues? I'd be seeking advice on those issues first.

[Daniel Grant]

I understand Columbia used 5200 on all their keels. To show the strength of the joint they sailed one of their boats from California with no keel boats, only the 5200 holding the keel on. I have had 2 Columbias and have never had a problem with the keel joint. The one I currently have, an 8.7, was made in 1974. I have had zero problems with the keel joint and the keel bolts a over sized stainless alloy and they and the nuts look like they were installed yesterday. It appears if done right the first time there should not be any problems later. I suggest sail and enjoy it.

[roverhi]

Actually think 5200 is the right caulk for the keel to boat joint. You want something that will hold with the flexing that inevitably occurs between the lead and the fiberglass. Never glass over the joint between the hull and keel. It will always suffer from the flexing between the two materials and allow water to infiltrate. Not such a big thing with a lead keel but a rust magnet for cast iron.

[Michael Pope]

I have written about his problem for years. I remember before there was 5200
There was Locally made adhesive (Vancouver BC) used for caulking between pours on Large Power Dams . It was made under patent from the Thiokol Corp who developed "Polysulfide Rubber"for sticking the propellant together in ICBM Rockets. It was later made by 3M as5200
A thunderbird 26' that had a cast iron Keel with a flange around the top
Had a leak so the owner asked me to take the keel off and re seat it. Took all the bolts out shook it with the crane wedges all we could think of-no move. We eventually made a custom knife from a Confectioner's Iceing knife with a very small high pressure water jet attached, fed by a power-washer pump it worked It would cut thru a Car tire like butter. I lost a lot on that job.
But I learned. Only use a thin small horizontal bead around the periphery of the keel with 5200 fill the rest with a weak in tension sealer. That will leak.
This is the root of most of the 316 Stainless steel keel bolt failures. That have cost many lives. It is too good a sealer. 316SS is only non corrosive if it has Oxygen to form Chromium oxide on its surface. The SS and other things can use up the oxygen available in the minute amount of space left on a well made seal. The bolt is stressed and stretches, minutely and cracks the Oxide Film and has no oxygen to seal it so the crack keeps growing . With a less effective sealer it would get fresh Oxygen dissolved in the sea water. So 316SS is not a suitable material for Keel bolts . Use Monel or use Steel galvanized or other so it rusts and weeps and tells you it needs replacing. If you are too poor to buy Monel and sleep well. Mike Pope

[robert sailor]

I think 5200 is a good choice for a keel joint, it's a very good bedding and a terrific adhesive and keels are not something you should be removing anytime as long as the seal remains intact.
If your keel bolts/nuts are mild steel and that's actually a good choice as they are not subject to crevice corrosion plus they are stronger than stainless.
Simply get in there with a good brass wire brush or a brass wire wheel on your portable drill and clean off the rust. Once really clean you might need a bit of acid to remove rust in hard to get at spots and then apply a half dozen coats of 2 part epoxy paint to protect them. Check them yearly and touch up the paint as needed.
There really isn't a need to undo the nuts unless the rust has really compromised the amount of steel remaining on the nuts. It usually looks much worse than it is before its cleaned properly.
The previous owner should have done a bit more homework and simply used a much less tenacious bedding/adhesive than 5200 on the keel studs as the studs only need some decent bedding material applied to the last inch or so below the fibreglass and nut.