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Discussion Starter #1 (Edited)
When I bought it two years ago, my '79 San Juan 28 had seawater seeping in around a few of its keel bolts. (Fiberglass hull, exposed lead keel with (8) five-eighths-inch stainless keel bolts through ~2-inch-square backing plates under stainless nuts.)

I staunched the flow with neoprene o-rings under backup stainless fender washers.

Now I'm on the hard, and want to seal whatever spaces there are hidden in there. The boat's supported by its keel and boat stands, and I'm ruling out totally taking off and re-bedding the keel.

I'm thinking that, over the next couple of months, I should:
  • one-by-one, pull off the original nut, backing plate, & any additional o-ring & fender washer;
  • replace each nut with a castellated nut, upside down on a 3/4-inch washer, to allow passage of fluids;
  • flush first with distilled water, to carry out whatever salt I can, & let dry;
  • flush next with acetone, to help dry out the moisture;
  • run in some penetrating epoxy to fill the voids, until it won't take any more;
  • reinstall the original nuts, plates, etc., & torque 'em down.

(BTW, externally I'm replacing the gelcoat with a barrier coat below the water line -- the boat has a serious case of the pox.)

Am I off in the weeds, or on the right track? Thanks for any impressions you might share.
 

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by trying to seal where the water is on the inside of the boat, all you are doing is sealing the water into the laminates of the hull creating more problems. to repair this properly you will need to drop the keel and sandblast the top down to bare metal, seal it with epoxy, dry out the keel socket in the hull, seal this with epoxy then rebed the keel with a true bedding compound, like sikaflex 291. if you are not planning to do the job right you will never be able to stop the water completely. what you will end up with is delam in the hull and severly corroded bolts and lead turned to chalk between the top of the keel and the interior of the hull. my advice is to repair it right or sell the boat.
 

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I ditto SVTFW's comments and further add that if you have had long term salt water ingress you could very well have crevice corrosion in your keel bolts that can only be seen and dealt with by dropping the keel.
 

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I'll sing with the choir. There's a reason the job is done that way--and not with the creative use of castellated nuts. Do it right, and you'll only have to do it once.

And if you use 3M 5200...the keel will stay on even if the bolts fail.(G)
 

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Good luck and keep us posted. I'm a fiend for photos, so please snap a few!

I think you'll find that this isn't too bad of a job and that it will give you a great deal of peace of mind. On the list of things I don't want to worry about while underway, the keel is right at the top.
 

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Discussion Starter #8
Thanks for that.

I'm assuming I brace the keel, loosen the bolts, and jack the hull up with well-placed boat stands. (Someone else had done a keel in the boatyard a few months ago.)

Relevant details must have been previously posted here -- do you know where? Do you know of a book that covers the process?

Thanks again.
 

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It is best to do the work in a yard that has a travel lift. keep in mind that any reputable yard will require taking down the rig before removing the big heavy counterweight at the bottom of the boat. after removing the mast, you will want to remove the fasteners from the inside of the hull and have the travel lift come pick the boat off of the keel and set it down beside it on boat stands. the dificult part may be seperating the keel from the hull enough to drive wedges in between the keel and hull. two years ago I tried to remove my iron keel from my coronado 41 to change keel bolts and rebed/reseal the keel. I had severe corrosion all over the exposed areas of the keel. with the nuts removed from the keel bolts I had the travel lift pick up the boat, but the keel came with it. the 34 year old sealant held the keel in place so well the faring compound didn't even crack when we tilted the boat at a 45 degree angle. I had no choice but to have the keel sand blasted in place and re-sealed without accessing the top. but my story is diferent, my keel was not leaking, I just wanted to go the extra mile.

WARNING: trying to use bottle jacks to raise the boat off its keel is very dangerous and could kill even the most attentive and competent shipwright. if you value your life, hire a travel lift.

joey
 

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Discussion Starter #11 (Edited)
Thanks for the warnings

As I hear more about dropping the keel (removing the rig, using a travel lift, etc.), it's sounding like this project is maybe a couple years down the road. Having to grind the gelcoat and apply a full barrier coat came as a nasty surprise -- I'm not sure how many more such surprises my increasingly skeptical first mate will tolerate!

So, yeah: it'd be great to pull the keel, and I DO want someday to take down the rig for inspection, service, and replacements -- just not yet. Realities demand I look for a way to hold the line on further expense for now.

So, it's looking like some variation on my original plan. In fact, I'd already obtained a second set of stainless nuts and posted them above the originals, and I'd only tightened them firmly -- thinking the more thread actually or potentially engaged on each bolt, the better.

The water is indeed seawater. (I wonder how much lead I ingested the couple times I tasted it?) The flow was very slow -- really a seep of a mere ounce or less per week. As noted in my original post, the o-rings and backup washers sealed the bilge completely. (I did also have a trickle down the starboard chain plate, but that was a separate issue, and also successfully addressed.)

I've ground away the gelcoat and paint around the keel/hull attachment, and don't see any pervasive, all-around cracking. (That's suggesting to me that the keel hasn't been especially loose.) There is a noticeable vertical cracking/flaking of the fiberglass along the trailing edge, immediately beneath the hull, with obvious loss of whatever fairing compound may have been there. Also, there were a few places where the fairing compound had blistered (like the gelcoat blisters, but much larger). I've dug those out and will be grinding out any detached fairing compound before re-fairing the hull.

The above is why I think some sort of flushing & penetrating (runny) epoxy approach will help for, say, a couple of years. I've got a month or so of heated drying (of the hull itself) coming up, so I'll let some water run down the keel bolts from the inside and see where it comes out.

MUCH thanks for your thoughtful and considerate responses. I do appreciate your time and your perspectives. (And yes, I consider myself duly warned.)
 

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Discussion Starter #13
Thanks for that

My boat has what Don Casey's book describes as "the pox" -- little bitty blisters all over the hull below the water line. A look beneath the gel coat shows what appears to be a layer of randomly-oriented fibers & resin (chopper-gun stuff?) with layer(s) of (presumably hand-laid) cloth beneath that.

It's the layer just below the gel coat that has myriad superficial shallow spots of separation, the larger of which would exude a drop of fluid when the swelling gel coat above was punctured. As I sand away the gel coat, little spots of moisture appear on the sanded surface -- obviously moisture exuding from damaged spots in the affected layer.

I've got Don Casey's directions for following up -- so while I can not yet get to the keel attachment (nor the mast, nor standing rigging, nor . . . ) I am, I think, going to do the pox fix "right". (One major fix at a time!)
 

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The water is indeed seawater. (I wonder how much lead I ingested the couple times I tasted it?) The flow was very slow -- really a seep of a mere ounce or less per week. As noted in my original post, the o-rings and backup washers sealed the bilge completely.
If it is leaking you are far better off to let it continue! Sealing it only traps the water and cause it to become deprived of oxygen which exacerbates and can accelerate crevice corrosion. You are much better off to leave it alone if you are not going to address the issue as this will allow some oxygenated sea water to "pass through"..

Crevice corrosion:

 

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Discussion Starter #15
Dramatic, scary pix, but less oxygen = more corrosion? I'd call that counter-intuitive, at the very least. (But then, as must already be obvious, I ain't no expert!)

Is this another issue upon which the opinions are (nearly) unanimous?

Thanks to all who are hanging with me while I mull this over -- it's appreciated!
 

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Crevice corrosion is a problem in salt water because of the low PH. The naturally occurring chlorides in sea water pit and eat the passivated surface of the stainless where the low PH of the seawater is in contact with it. Because it lacks oxygen, hence crevice, the stainless can not self re-passivate to fend off this attack and the corrosion continues on. Crevice corrosion is most prevalent in oxygen deprived areas like keel bolts or areas starved of oxygen but that have access to salt water via leaks.
 

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Discussion Starter #20
. . . significantly more of a safety danger than the pox . . .
No argument here. Too bad I committed on the "more obvious" problem before I started inquiring about the sleeper.

(Guess I'd better get something like Casey's "Inspecting the Aging Sailboat" and read it through.)
 
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