Sealing weeping keel bolts.

[jviss]

I know this is a well-worn topic, and that I will get a flurry of links from Stu Jackson, but I have a very specific question, narrowing the topic quite a bit, and I would really like to get Mainesail's view on this.

I think I'm making water through the keel bolts on my 1984 Catalina 36. Once, about 10 years ago, I torqued the nuts to 105 ft-lb. I haven't since, and the water increase is recent.

I've read everything I can find on the topic, with remedies from removing the keel and re-bedding, to simply tightening the nuts; in or out of the water is debatable.

One thing that has a lot of appeal is to remove the nuts one at a time, applying some kind of sealant, and then replacing and tightening the nut. The generally recommended sealant is 3M 5200 (yes, Satan's glue).

I'm inclined to try this while in the water, having dried the bilge as well as I can, observe any water entering, but probably do all nuts, one at a time.

Here's the question: what sealant? 5200, 4200, flax packing, butyl tape?

 

[Don S/V ILLusion]

This is one of the few areas where 5200 makes sense and used for it's intended purpose

 

[Stu Jackson]

John, you can't do it in the water. Why? One of our gurus said it simply: "You can't lift 5500 pounds of lead on a single bolt."

http://c34.org/bbs/index.php/topic,6842.0.html

Link? What link?

 

[jviss]

John, you can't do it in the water. Why? One of our gurus said it simply: "You can't lift 5500 pounds of lead on a single bolt."

Thanks Stu. I don't agree with this statement, exactly. Perhaps you can't with a single bolt, but you can with all the bolts. Per the link you posted:

"I lifted the keel up with the bolts and tightened a bit. Those bolts have no problem lifting the keel. "

Think about it. If you can turn the nut, you are either lifting the keel, or stretching the stud, or compressing the keel stub material, or all three. And, in the water the keel effectively weighs less than out of the water.

So, why can't you do this in the water? Are you assuming that the keel need be blocked, with the hull sitting on it to get enough compression to tighten the nuts? I would disagree with that theory.

Regarding 5200, that might make it really tough to separate the keel if it was ever necessary.

 

[jviss]

I got off track here myself. The question is "what sealant?"

 

[Stu Jackson]

And, in the water the keel effectively weighs less than out of the water.

So, why can't you do this in the water? Are you assuming that the keel need be blocked, with the hull sitting on it to get enough compression to tighten the nuts? I would disagree with that theory.

Regarding 5200, that might make it really tough to separate the keel if it was ever necessary.

How much less? I used to "do" physics, not so much lately.

Why not ask right on the link I posted? They seem to have "some" experience.

 

[Rob19574]

I would be interested to hear what Maine Sail has to say.

My take is that the water coming in thru the keel bolts is coming in externally obviously via the keel stub (where the hull meets the keel). You need to seal this up to stop the ingestion of water. That seawater will cause crevice corrosion on the keel bolts (ss will corrode in absence of oxygen). I would wait until your next haul and address the external leak first -- then move inside to torque the nuts and seal them up. If the leak today is fairly recent and you really want to seal such - then use 4200.

- Rob

 

[philwsailz]

Rob brings up a good point. I would rather personally have a leak, if it were a small one, allowing the oxygen-rich fresh water to flow past the SS bolts, as opposed to stopping the leak internally, and dooming the water next to the SS to slowly stagnate and start eating away at the bolts.

To my mind, the fix needs to happen externally on your next haul-out, less you find you ARE hauling out to fix the proiblem you introduced with the internal sealant, whichever brand or type it might be.

 

[jviss]

I personally think that all of these boats have water between the keel and stub, and that you only notice when the bolt starts weeping. Sure, you could fix it "right," by separating the two and bedding the keel to stub joint with something - I don't think there's a consensus on what that should be - or, you can go on after sealing the bolts on the inside for another 28 years.

I think it's reasonable to address this as two separate issues: sealing the leak; and then addressing the longer term issue. The first is a more immediate concern, and probably easily, quickly, and inexpensively fixed. The second is a big job, out of the water for weeks on end, and probably quite expensive.

This post: part one. What sealant?

 

[Stu Jackson]

The link I provided said this in the very first post:

"I did do the sealing of the keel nut washers the year before, however this was not successful. Water came up around the washers after a few weeks. This method may keep the water out of the bilge, but it does not eliminate access to your keel bolts from the lake or sea, and I'd really like to seal this one up like it's supposed to be."

While I am sure you might have read that, perhaps you missed it in your review, since the post was pretty good and had great pictures and text.

The C34s and C36s are pretty much the same boat construction.

I recommend that in addition to this forum you ask away on those, too. Tom Soko, who recently purchased a C400 (I believe) remains very active on the C36 Forums and personally is a wealth of knowledge. I'm sure this has been discussed on the C36 board, as well as on our C34 board, and it wouldn't hurt to find out what their experiences have been (unless you have it already on your C36IA Tech CD-ROM).

Seems our linked C34 skipper's experience on just bedding the bolts didn't work, at least for him.

Good luck.

Also said in that link:

I lifted the keel up with the bolts and tightened a bit. Those bolts have no problem lifting the keel.

Guess our guru was wrong! Me, too!

 

[Rob19574]

I would use no sealant on the bolt / nuts at the moment -- it may do further harm. On your next haul for paint, clean out the hull to keel joint (before they paint) where you have a separation and fill it in with 5200....then do the same internally to the bolts. That would be the quick fix on this. I am sure there are more detailed and permanent ways to fix the keel joint but that is a quick and simple fix. Your probably fine for the season allowing the bolts to weep.

 

[jviss]

...oxygen-rich fresh water...

What fresh water? Unless you mean fresh salt water, as opposed to stagnant salt water.

 

[jviss]

(before they paint)

Who's "they?" That would be me; or more precisely, my wife.


I can't see what harm sealant under the washers would do.

 

[zeehag]

either dowhat stu sent ye

OR

haul, separate the keel, rebolt, and for more permanence and peace of mind, fiberglass the joint after rebolting, for more security.

 

[FastOlson]

I know this is a well-worn topic, and that I will get a flurry of links from Stu Jackson, but I have a very specific question, narrowing the topic quite a bit, and I would really like to get Mainesail's view on this.

I think I'm making water through the keel bolts on my 1984 Catalina 36. Once, about 10 years ago, I torqued the nuts to 105 ft-lb. I haven't since, and the water increase is recent.

I've read everything I can find on the topic, with remedies from removing the keel and re-bedding, to simply tightening the nuts; in or out of the water is debatable.

One thing that has a lot of appeal is to remove the nuts one at a time, applying some kind of sealant, and then replacing and tightening the nut. The generally recommended sealant is 3M 5200 (yes, Satan's glue).

I'm inclined to try this while in the water, having dried the bilge as well as I can, observe any water entering, but probably do all nuts, one at a time.

Here's the question: what sealant? 5200, 4200, flax packing, butyl tape?

"None of the above."

1984 is plenty old enough for it to be time for a rebed. Lift the boat off the keel, check those leaking threaded rods for corrosion (and hope there isn't any significant amount!), and then clean up the mating surfaces super well, and then rebed with good sealant. New nuts and washers/plates would be good, too.
Then you're good for another 20+ years.

To borrow a riff from that HGTV remodeler, Mike Homes, "Fix it Right" !

 

[FastOlson]

To be Blunt: "Bad Idea"

Who's "they?" That would be me; or more precisely, my wife.
I can't see what harm sealant under the washers would do.

Imagine sealing the leaking water from the top (i.e. under the washers) and then the confined moisture, in an oxygen-starved interface with the ss threaded rods, corroding the rods away.
Seen it. Awful sight. Takes lots of money to remedy.

Please do not do that.

BTW, do not look at this as a "Catalina thing" but rather an issue that afftects all external keels, sooner or later.
Internal ballast boats have their own completely separate concerns, so they need not feel smug, either....

 

[jviss]

Imagine sealing the leaking water from the top (i.e. under the washers) and then the confined moisture, in an oxygen-starved interface with the ss threaded rods, corroding the rods away.
Seen it. Awful sight. Takes lots of money to remedy.

Please do not do that.

BTW, do not look at this as a "Catalina thing" but rather an issue that afftects all external keels, sooner or later.
ternal ballast boats have their own completely separate concerns, so they need not feel smug, either....

Where did you see it?

By the way, water is not necessary for crevice corrosion, just lack of oxygen. Where does the oxygen come from if these things stay dry?

 

[Maine Sail]

Here's my take as one who actually had to re-bed a Catalina keel due to the laminated plywood used in the stubs getting wet and causing severe corrosion of the keel bolts..

#1 If the bolts are weeping let them weep or fix them correctly by removing the keel assaying the wood core and removing it if necessary then re-bedding the keel. Top sealing is nothing more that a feel good measure that may create more bad then good.

#2 Sealing the washers will only cause stagnant seawater to become trapped in no-mans-land and can lead to accelerated corrosion of the keel bolts. Allowing some fresh oxygenated water to pass through is not such a bad thing if it is leaking and your bilge pump can keep up.

The good: I don't know of any Catalina's that have lost a keel though ours was barely hanging on and the bolts were 1/3 the size they should have been.

They looked very similar to this:

The bad: No Catalina keels have fallen off YET!!! Knowing what some of these look like when dropped, and seeing how badly the bolts are wasted away, it scares the bejesus out of me to think of all the Catalina's out there sailing around not knowing what is happening in "no-mans-land"...

If you own a pre 1987 (some models) or pre 1988 (some other models) the wood in the stub will eventually become an issue. As the wood gets wet it compresses and allows the keel to move more than what the sealant can handle. A leak starts. Once leaking there is really only one true fix...

The fix: The only true fix, if outside water is entering around the keel bolts, is to drop the keel and re-bed it. Anything else is a bad-aid that may cause more harm than good. While you are in there it would be a very, very good idea to get rid of the plywood core. Plywood does not belong in the fiberglass keel stub of a fin keel boat... If you drop it and find corroded bolts Mars Keel in Canada and Broomfield in RI can actually replace the bolts with brand new ones, and do it the right way...

Sadly with these boats getting long in the tooth, and most owners unaware of what is or could be going on, I worry that we will soon be hearing of more keels dropping off .... Scary stuff...

Really, how much did they save by embedding plywood.........:cussing::cussing::cussing::cussing:

PS I did not have time to read the thread so if I repeated stuff others said, sorry....

 

[philwsailz]

Imagine sealing the leaking water from the top (i.e. under the washers) and then the confined moisture, in an oxygen-starved interface with the ss threaded rods, corroding the rods away.
Seen it. Awful sight. Takes lots of money to remedy.

Please do not do that.

Hey, that's what I said!!!

 

[jviss]

#2 Sealing the washers will only cause stagnant seawater to become trapped in no-mans-land and can lead to accelerated corrosion of the keel bolts. Allowing some fresh oxygenated water to pass through is not such a bad thing if it is leaking and your bilge pump can keep up.

Thanks. It's weeping, not much at all, I don't think. I wonder about that statement, though. Do we know that the trapped water is indeed stagnant? How much of a factor could that be?

I know about the "proper" fix, but I'm not planning on ending my sailing season to fix this, but I wouldn't mind stopping the weeping now.