Keel bolt nightmare

[merrydolphin]

I’m sorry that you are having this problem. I know this doesn’t help you any but in 50 yrs of owning keelboats, I have always gone for encapsulated ballast, preferable lead. But the one boat that I had that wasn’t lead, a Kelly Peterson 44, had iron punchings with concrete, and none of them ever gave me any trouble of any kind with 10’s of. Thousands of miles of cruising. good luck and again, sorry.

[hirondeller]

Maybe not a nightmare at all.


Posts #8 & #57 deserve reiterating and some expanding. How about a 1/2" drive electric automotive impact gun (if a compressor is not available)? Turn the torque setting up one step at a time. The high frequency hammering action really does help, hammer a few minutes at low power to break the corrosion; soak, then apply more acetone/ATF (or, liquid wrench, or whatever brand) right before hammering.



If you round off a hex, that is a lot better than breaking the bolt off inside the keel. Remember that there are some sockets that are designed to 'bite' on a rounded hex head.


Best of luck, they might just spin off.

[hirondeller]

Upon further reflection.......


If you practice this first on a vise, you might be surprised at how easy this is.



These are studs with hex nuts, correct? If so, cut a slit in the rusted nut with the 'right size' abrasive disk (dremel or high speed grinder, air powered, or electric versions abound). Go as deep into the nut as you can without hitting the threaded stud. Insert a chisel into the slit and give a sharp smack. The nut will split open, once the pressure is gone it will turn right off with any wrench. Or, try a 'nut splitter', where the chisel is turned inwards by the action of a screw.



Best wishes

[Manateeman]

Hi. I think you ought to examine some way to lift the hull or drop the keel just a few inches. It seems you have three, no one problems. I’ll start with the destruction of the existing bolts / nuts. One removes the water or chooses a metal which works under water. This is why I suggested silicon bronze. I guess you could use titanium. What clearly might fail without looking bad, is stainless.
It is very difficult to prevent water from getting at the bolts. Builders have tried all manner of magic adhesives. They tried an band set into both the keel and a stub keel which was part of the hull. The band a high strength glass set in a flexible epoxy. Worked ok unless you had a grounding. If you sail into an underwater obstruction, and the leading edge near the bottom of the keel hits something solid, a huge force pushes up into the hull where the surface area is very small. The hull gets stabbed by the fine taper of the keel. The forces are enormous. I’ve seen all the internal structure designed to spread the keel loads pulled cleanly off inside the boat, the plywood cabinets crushed, the engine bed
tabs split. The keel attachment to the vessel relies not only on the bolts, but the design, condition and strength of the area where keel and hull meet.
If you are limited to stainless bolts, please, use Ted-Gel on the threads so you can remove them for inspection. Please Lightly grind all the glass inside and out.
Check for any damage. Consider adding reinforcement glass set in epoxy. I’m concerned about the surfaces between the keel and the hull if you cannot seperate them. You have three issues. 1. The current strength of the hull at the keel...has it been compromised...if so, can you spread the load out further inside the hull. 2. Replacing the bolts and backing plates. 3. How to keep the bolts safe from corrosion in the future.
When I began building wooden boats, we had the keel / hull issue. I remember Larry Pardy had elegantly cast bronze floors made to spread the keel hull loads.
Today you could construct them with modern materials but the purpose would be identical. Please let me know if I can be of further assistance.
Mark the manatee and professional boat builder.

[mitiempo]

Originally Posted by Manateeman

Hi. I think you ought to examine some way to lift the hull or drop the keel just a few inches.

What clearly might fail without looking bad, is stainless.

When I began building wooden boats, we had the keel / hull issue. I remember Larry Pardy had elegantly cast bronze floors made to spread the keel hull loads.
Today you could construct them with modern materials but the purpose would be identical.

No sense using anything except fiberglass and epoxy if strengthening the keel stub is desired. Biaxial would be my choice. Of course hull thickness is unknown until the keel is dropped.

Stainless is not at risk inside the boat, but where it is buried in the keel and the stub. As long as the joint is kept dry there is not a problem. Virtually all bolt on keels on US made boats use stainless. The best way is to get a perfect mating surface between keel and hull, not a varying gap filled with sealant. Drop keel, clean both surfaces, install bolts in keel, lay plastic over keel top with holes for the studs. smear thickened epoxy on the bottom of the stub thick enough to fill any expected gap. Lower boat onto keel and let sit a day. When the boat is lifted the 2 surfaces should be perfect mates. Remove plastic. Then apply sealant of choice around studs, thickened epoxy over the rest of the keel top, and lower the boat onto keel. Tighten bolts but not torqued all the way yet. clean up squeeze out between keel and hull. Wait a day or two and then torque nuts to final setting. The bolts should stay dry for years or until you hit that rock.

[Manateeman]

Hi. There is a lot of information on Beneteau keel bolt replacement on the YBW forum. This includes replacement without lowering the keel. I’m not endorsing this approach, simply pointing out more information is available from Beneteau owners who have tackled the problem.
Regards, Mark

[Pitchondesign]

A little off topic, but there has been discussion of dropping the keel to deal with a keel bolt problem. Is it possible to drop the keel if it has been previously bedded with 5200? I did a quick check and it seems that the bonding strength of 5200 is 3x the weight of the keel given the contact surface on my boat. I have no direct experience with this, but have read reports of removing keel bolts, lifting the boat, and the keel refuses to come off due to the 5200 adhesive. Thoughts?

[BBill]

Originally Posted by Pitchondesign

A little off topic, but there has been discussion of dropping the keel to deal with a keel bolt problem. Is it possible to drop the keel if it has been previously bedded with 5200? I did a quick check and it seems that the bonding strength of 5200 is 3x the weight of the keel given the contact surface on my boat. I have no direct experience with this, but have read reports of removing keel bolts, lifting the boat, and the keel refuses to come off due to the 5200 adhesive. Thoughts?

My personal experience shows 5200 got rock hard (like a bowling ball) and brittle over 10 yrs on one of my old glass boats. I originally applied it so I know it was 5200. It wasn't nearly as tenacious as new and had hairline cracks everywhere. It may have been a bad batch but I've seen the same results posted by one other person. I don't know if this applies to the keel bedding but it does align with sailboat hull to deck leaks reported on older boats that were bedded with 5200. I don't use it anymore but guessing it would be near impossible to get a keel loose even with what I've experienced.

[Manateeman]

Hi. Find a fiberglass boat builder. They usually have a pile of very strong plastic wedges as well as hardwood. Disc grind off bottom paint till you can clearly see the line where the keel joined the hull. If the hull has a “stub”, you are in luck.
Sometimes there is a band, like an ace bandage, of glass in epoxy set into the stub and the keel. Bit more work to remove. Once you are sure you have the joint, open it up with a thin metal cutting disc on a grinder. You might get 1/2 “ in.
You might be able to drill parallel to the surface of the joint with long aircraft bits. You might get a saws all blade into the joint. If you can, don’t cut the bolts. Lots of wedges. Boatbuilders have all had parts stuck in the mold. Service yards might give you some background on your boat. The theoretical strength of adhesives is often measured in a lab after perfect application under ideal conditions.
Post some photos of the joint and please let us know what other Beneteau owners have done. I understand there might be a factory keel bolt kit ?
Regards, Mark

[theoldwizard1]

Originally Posted by slug

High class boats have lead keels


Ferrous keels are s huge compromise

https://www.constructionspecifier.co...uctural-steel/

Rust jacking , when rust gets into the keel hull joint , is so powerful that it can pull keel bolts thru the GRP laminate

Yes, rust "jacking" is extremely powerful, but it usually takes a large surface area before it can have an affect.

[CHM]

I replaced my keel bolts about 5 yrs ago. You can probably search for that thread. Anyway, I have a 1988 Beneteau 430 and the keel bolts were original. I see a lot of misinformation in this thread and I can tell you 100% that the keel is cast iron and the bolts are galvanized steel. My bolts broke lose with a 3/4 inch impact wrench. I did not have to drop the keel etc. The bolts were actually in pretty good shape except for the heads. You’re not going to see a lot of rust unless air gets to the bolt and that’s not happening in the keel under the water line. I did have surface rust on the keel itself which is mostly from it being hauled for months before I bought it. I had it sandblasted and barrier coated. I will try to attach a recent photo. Good luck with your project.