Bolt on Keel Issue

[Carl-T705]

Well, you certainly received a plethora of responses here. Might I suggest this, it's not as glamorous as some responses but it may shed some light where there is darkness. Get a wire wheel brush on a hand held grinder and clean up all the bolted/fastened surfaces and then go to the exterior hull surface and clean up the keel to hull joint removing what looks like a lifetime of bottom paint and sealer. Take it right down to the gelcoat. At this point, post more pictures and perhaps it may look a little less ugly or it may really show damage. Even a banana has to be peeled to reveal the condition of the fruit. Cheers

[jroberts]

I have a 1984 C&C. We pulled her out in February for new standing rigging and some cosmetic work (new gelcoat in the cockpit). The first thing my rigger recommended when she came out was to check the keel. It had some play which contributed to the "smile". Everything looked good from the inside of the bilge. It was only when we dropped the keel that we found two of the keel bolts were corroded. But more importantly we found delamination in the keel stub (I hope I have the correct terminology here) due to poor workmanship 20-30 years ago in a repair. We had to make a tough decision, spend more on all the fibreglass work (grinding to good glass then build it up, two new keel bolts, etc) than the boat cost us, or scrap her. I do almost all my own work because I enjoy doing it and I want to know how it all works and goes together so when offshore I have some idea on how to fix it. That being said, in hindsight, the safety issues and critical component meant that I needed to rely on expertise. I could have paid someone less to do the work but at the end of the day we bit the bullet and paid someone with the best reputation in our area. We spent a lot more than we ever wanted to but decided that we would invest in this beautiful boat and use it for the next 20-30 years instead of scrapping her. I can't tell anyone what to do, but this is one area that you should not mess with and need to fully investigate. To me it's like a crack in the foundation of your house - yes you can cover it with filler, but what's behind the problem that's holding your house up?

[Icarus]

Originally Posted by USA1791

Hey,

Have a question of what to do. One of the sections of the bolt on keel is rusted. The whole backing plate is basically dust, when I touch it, it just crumbles.

It looks like 2 sections of the bolt on keel has been replaced before since the backing plates look different. Does anyone have the best way of removing it? Talking to some people about it and they said I have to be careful so as not to mess up the bolt and make it harder to take out. I’m hoping it’s not rusted all the way through though.

My question is:

1. Should I go ahead and replace all of the bolt sections, or just do the rusted part?
2. From my understanding, there shouldn’t be a reason to removed the keel. I would just need to get the rusted bolts out and replace?
3. I checked the outside of the keel and have noticed some rust around the keel/hull touching.

Attached are some pictures to get a better idea of the issue.

It depends on how the keel bolts are fastened in the ballast keel.
Some times they are actually part of a frame which has been cast into the Lead ballast keel Not good
If your keel is cast iron they will be screwed in. To remove the bolts might be not so easy as the the corroded bolts don't have anything to grab on in order to unscrew them.
Welding the nut on the bolt to be removed might overheat the substrate and in any case might just snap the bolt if it's seized.

As a shipwright we removed a number of bolt on keels in the past and generally dropped the keel to get access to the bolts.
We used a ship lift or crane to lift the boat off the keel after the nuts have been removed of course.

Trouble is crane fees are expensive.

Hope it helps

[Icarus]

Originally Posted by Jim Cate

Mark, if the owner is able to pull the studs (and they are not bolts, folks) one at a time for inspection, and if they do not show corrosion in the area below the hull, why would he need to drop the keel for inspection? Such joints often have corrosion at t he outer edge of the join, corrosion that does not propagate inward and cause damage to the suspending connectors. And corrosion in the bilge isn't specifically related to the unseen areas below, is it? Replacement of the studs, nuts and backers is, of course, mandated.

If there is damage to the fiberglass in way of the studs, then yes, dropping and repairing is indicated. However from my reading of his posts there is no evidence of such damage as yet discovered.

A side observation: professional repairers are often quite willing to encourage owners to spend their money on repairs, citing "what-ifs" to support their viewpoints. Such repairs may or may not be essential to basic safety considerations. Making low cost inspections (like drawing the studs for inspection) is a viable first step before committing large sums to a possibly unnecessary procedure.

And yes, I am one of your despised non-professionals, but I've been around boats for a good chunk of my adult life and seen a lot of bad advice proffered by "experts".

Jim

Not quite sure what you suggesting, Why is it bad advise to remove the keel in order to replace possible corroded keel bolts?
It pretty obvious, according to the pics, that some bolts have been compromised.

[Icarus]

Originally Posted by Dymaxion

Gad!! The truth is in the studs, not in anyone's amateur or professional opinion. Fear mongering and what-ifs are invalid. Stick a 6-sided socket that you know is the correct size, not oversized due to rust, and unscrew the nut!! Meaning clean the nut off thoroughly on all six side and fit the snuggest socket on you can. If the nut begrudgingly comes loose, then the stud is solid enough that a fresh new nut and well cleaned up threads will allow you to retorque it to builders spec. If the nut and stud come out together, hooray, you can put in a new stud, new nut and have at it. Okay, so your keel has been loose for years, wobbling about a bit and allowing water to enter from below the waterline. Have you tasted the water to see if is salty? Or fresh from intrusion via the cabin top. If it's fresh water, congratulations, your keel is water tight. If it's salty, then you need to reseal it. Find out if your keel is flush mounted, drawn up against a flat surface, with a layer of sealant/adhesive between the top of the keel and the hull. Or if it is fitted up into a pocket within the hull. In either case, get an angle grinder with a very thin cutoff blade in it. Use the thin blade to clear out the old sealant. You could lower the keel a bit, but why bother. Buy a cheapo mini grease gun, buy the hypodermic needle tip and some empty cartridge tubes. Full the tubes with your favorite sealant, jam the needle well into to slot you just cut with the angle grinder pumping sealant in until it appears at the surface of the keel joint. Move the needle around the keel seam an inch or do at a time and keep pumping in the sealant until done. Go back inside and torque your keel boats up to spec. Wait 5 minutes and retorque. No, I'm not a boat builder, just a tired old aerospace engineer who likes low buck common sense solutions, not the freak out end of the world pronouncements by professionals, who in their world are correct, dropping the keel is the absolute best way to go. But if you've verified your keels bolts are good enough to take full torque, then your keel is not coming off, and if you've sealed up the cracks/leaks, what else is the to do... go sailing?

How do you verify if the studs are in good condition?

If they pass through a dead wood and metal reinforcement say 120mm?

Ultra sound?

Don't worry might be the 'low buck solution for a while.

[Jim Cate]

Originally Posted by Icarus

Not quite sure what you suggesting, Why is it bad advise to remove the keel in order to replace possible corroded keel bolts?
It pretty obvious, according to the pics, that some bolts have been compromised.

In short, it is a cast iron keel. The studs will be screwed into tapped holes in the top of the keel. It should be possible to unscrew them one at a time, in the water, for inspection. If when inspected there is no significant corrosion on the shanks or threads of the studs, then there is no real need to drop the keel.

And yes, the NUTS and the exposed portion of the studs there in the bilge, as well as the backing plates are compromised. Obviously they should be replaced with new, a simple and inexpensive task.

IMO, the bad advice is to automatically assume that there is corrosion to the studs and to thus drop the keel as the first step, an expensive and time consuming step that may not actually be required. If in fact there has been water intrusion and corrosion below the backing plates, only then would he need to undertake the dropping exercise.

If it were my boat, I'd approach the issue in steps, beginning with the easiest and least expensive and if required, escalating the repair as needed.

His boat, his choice... it's his money!

Jim

PS Inspection of the glass around each stud would be part of the process. If there is damage to the glass, then dropping and repairing is mandated.

[5BTM]

Perfect job for an induction heating tool.

I would do myself, but as a retired contractor, I have all the tools and then some.

The purchase price of the boat is "sunk cost" and should have no bearing on your future spending.

[kenbo]

Originally Posted by Icarus

Not quite sure what you suggesting, Why is it bad advise to remove the keel in order to replace possible corroded keel bolts?
It pretty obvious, according to the pics, that some bolts have been compromised.

As Jim Cate stated, they are not bolts they are studs screwed into the cast iron keel. As a shipwright, you should use the proper nomenclature.

The French manufacturers use a special galvanizing on these studs but I'm not sure if the nuts receive the same galvanizing. I'd contact Jeanneau and ask about the nuts and buy them from them if available.

But do not use SS nuts in that assembly.