Sealing keel bolts in epoxy

Solarfry · Mar 13, 2018

It keeps the nuts from galling or rusting in thread when there is wetness in area all the time. But makes it hard to re-tighten keel bolts yearly as required by most sailboat mfgrs.

dlochner · Mar 13, 2018

MightyMike said:
At any rate, I noticed the keel boats are encapsulated in clear epoxy a couple of inches deep at least.

I had never seen this before and am wondering if this some sort of acceptable repair.

Seems to be an odd arrangement. It makes it difficult to access the keelbolts. Removing enough epoxy to access the nuts might be a good idea. There is no way to know if one of the bolts is leaking and if there is any crevice corrosion going on. Not sure how you would remove that much epoxy, perhaps with a hole saw over each bolt?

MightyMike said:
The fiberglass tab at the stern of the keel is another matter, but that's a topic for another time.

Oh, and all the tabbing in aft bulkheads, hull laminate aft of the keel, and the keelboats, to mention a few other key areas.

Scott T-Bird · Mar 13, 2018

Keel bolts ... it's funny how some things you just don't know about. My boat is almost 30 years old. The bilge almost always has a little water in it when underway, either from the ice box or I don't know where. I can't seem to keep it dry during the winter, so there is always a bit of ice encapsulating keel bolts (and bilge pump & float).
The bolts and nuts are as clean as if they were brand new. The keel joint shows no sign of separation. I never see any leakage at the keel joint when the boat sits on stands. During the season, when I dry out the bilge for leaving and come back 1 or 2 weeks later, the bilge is usually perfectly dry (unless it has rained really hard). I have fretted with a wee bit of worry over it, but it seems if it ain't broke, don't fix it. I just can't work up enough worry to do any more than watch for signs of trouble. I've only ever loosened the bolts and tightened them again once. I'm thinking that there may be an adhesive holding and sealing the keel about as secure as it can be.
I've heard that keel bolts should be encapsulated in epoxy. I guess my thought is that until you see something to worry about, there is no reason to really worry. I'd just leave them encapsulated.

dlochner · Mar 13, 2018

Scott T-Bird said:
I've heard that keel bolts should be encapsulated in epoxy.

What is the rationale for encapsulating them? Curious minds want to know.

Scott T-Bird · Mar 13, 2018

dlochner said:
What is the rationale for encapsulating them? Curious minds want to know.

Well, the purpose that I have read is that encapsulating the keel bolts in the bilge prevents bilge water from seeping into the joint between fiberglass and bolt. I have read in at least one of the mags that keel bolts should be protected in the bilge, as it is almost impossible on most boats to keep the bilge dry. I'd guess that the advise on what to do is more varied than for just about any boat component. I've never heard universally that they should be tightened every year, or even periodically. I've also heard that a good bond with 5200 at the keel joint would effectively keep the keel on without need for bolts at all. Honestly, I've heard and read so many different things about keel bolts, that I am effectively paralyzed about doing anything until I see an obvious need to do something. That may come at the wrong time, I realize

. I figure my time is gonna come when it's gonna come and there isn't much I can do or worry about it!
I've also read that some keel bolts aren't even SS, which doesn't make any sense at all. I think I have read that Beneteau has particularly troublesome keel bolts. Mine are definitely SS and they must be one fantastic grade of SS because they appear as if they are brand new.

dlochner · Mar 13, 2018

Scott T-Bird said:
Honestly, I've heard and read so many different things about keel bolts, that I am effectively paralyzed about doing anything until I see an obvious need to do something. That may come at the wrong time, I realize .

Sometimes the internet is not as helpful as it could be.

Stagnate seawater is best for creating crevice corrosion, so I wouldn't worry too much about some bilge water that gets pumped out and exchanged.

My approach has been to re-torque the keel bolts every few years. It is not hard, when the boat is on the hard, loosen a bolt, inspect and re-torque with a decent torque wrench. It only takes a few minutes for each bolt. The biggest danger is over torquing and galling the threads, then nut won't tighten or loosen.

Slow and easy seems to prevent this.

If seawater somehow infiltrated the epoxy it would create ideal conditions for crevice corrosion.

Scott T-Bird said:
I figure my time is gonna come when it's gonna come and there isn't much I can do or worry about it!

I hear ya! I just want to delay the inevitable as long as possible. Sail fast, live long, die quickly.

Whatfiero1 · Mar 13, 2018

Just sail. And don't worry about it. On next haul out maybe 2 to 3 years from now check for keel smile. And if none. Don't worry. I 're torked bolts once and it's not necessary because they were close to spec

dlochner · Mar 13, 2018

Whatfiero1 said:
Just sail. And don't worry about it. On next haul out maybe 2 to 3 years from now check for keel smile. And if none. Don't worry. I 're torked bolts once and it's not necessary because they were close to spec

Two words: Cheeki Rafiki https://en.wikipedia.org/wiki/Cheeki_Rafiki

Whatfiero1 · Mar 13, 2018

Death is inevitable sailing should be done often

Scott T-Bird · Mar 14, 2018

Here is one article that I have read that indicates that it is normal for the bolts to be encapsulated within the bilge. I remember it because I found it alarming to me since my bolts, nuts and washers are totally exposed. There are also discussions in Sailnet and other locations that discuss this topic. The only consensus that I can discern is that there is no consensus. Interesting reading. My comment about Beneteau was finding out that galvanized bolts are used for iron keels. I don't know that I would feel more comfortable with galvanized bolts or SS, but it seems that the key is that if the keel joint is secure and the bolts are not continuously exposed to salt water, there should not be a problem. When I was in fresh water, my concern was far less. Now I'm in brackish water, so I am trying to pay more attention to these salt water issues.
https://www.sailmagazine.com/diy/how-secure-is-your-keel

dlochner · Mar 14, 2018

MightyMike said:
At any rate, I noticed the keel boats are encapsulated in clear epoxy a couple of inches deep at least.

The tops of stainless steel keel bolts are almost always encapsulated with resin to protect them from bilge water. Chip off a cap, and you are likely to find a mild steel washer beneath the stainless steel nut.

I think we're talking about different ideas. The OP said the resin was a couple of inches deep. Casey seems to talk about coating the bolts in resin that can be chipped off.

Entombing the keel bolts in resin, just seems like a really bad idea for reasons I've mentioned above and I don't think you could easily "chip off the resin" to access the bolts. Coating the bolts with a thin coat of resin or something else, like a grease or Lanocote to insulate the bolt from bilge water may have some merit, but I've not seen it done.

The issue with stainless steel and salt water is not the salt water per se, but it is SS in deoxygenated salt water. So long as the water is flowing, the SS will continue to have enough oxygen to preserve the thin layer of corrosion that protects the rest of the steel. That's why SS prop shafts don't develop crevice corrosion, while SS hardware, chainplates and other fittings that sit in stagnant salt water do develop crevice corrosion.

I'm going to stick with my naked SS keelboats, though it has been about 5 years since they have been retorqued. A project for this spring or next.

Gunni · Mar 14, 2018

My keelbolts are alloy (I assume stainless, since they stay shiny) and as in most Beneteaus they remain dry in a dry bilge. Casey refers to coating keelbolts heads with epoxy to keep them dry from water that drains to the bilge. If I saw a bilge that had been filled with resin, and the bolts encapsulated I would assume that the boat has a leaking keel to hull connection and someone was attempting to keep water from percolating up around the keel bolts. The other alternative is a keel stub that has been compromised, cracked and was leaking.

Scott T-Bird · Mar 14, 2018

dlochner said:
I think we're talking about different ideas. The OP said the resin was a couple of inches deep. Casey seems to talk about coating the bolts in resin that can be chipped off.

Entombing the keel bolts in resin, just seems like a really bad idea for reasons I've mentioned above and I don't think you could easily "chip off the resin" to access the bolts. Coating the bolts with a thin coat of resin or something else, like a grease or Lanocote to insulate the bolt from bilge water may have some merit, but I've not seen it done.

I also am not clear about what Casey is talking about with respect to encapsulating the bolts within the bilge. I also don't want to take that step to encapsulate mine. However, if Pearson encased the bolts as the OP describes, I also would not try to chip the stuff out unless I had a really good reason to do so. It seems to me that encapsulating the bolts just might be the best way to preserve their integrity so I would leave it alone if that is the way it comes and I didn't have any apparent problems.

Alan Gomes · Mar 14, 2018

Just as another data point, I used to own a 1984 Newport 27 and Capital Yachts encapsulated the keel bolts.

dlochner · Mar 14, 2018

Alan Gomes said:
Just as another data point, I used to own a 1984 Newport 27 and Capital Yachts encapsulated the keel bolts.

Can you elaborate, were the keelboats "painted" with resin or were they submerged in a pool of resin? The distinction being, if painted it would be relatively easy to access the bolts by removing the resin, whereas, if they were submerged it would take a lot more effort and the bottom of the bilge would effectively be above the keelboats.

Alan Gomes · Mar 14, 2018

dlochner said:
Can you elaborate, were the keelboats "painted" with resin or were they submerged in a pool of resin? The distinction being, if painted it would be relatively easy to access the bolts by removing the resin, whereas, if they were submerged it would take a lot more effort and the bottom of the bilge would effectively be above the keelboats.

Sure.
They were not just painted in resin but completely encapsulated. Over each keel bolt there was essentially a solid "puck" of resin. It would have been a heck of a job to do anything with those keel bolts as removing all that resin would have been quite an undertaking.

FastOlson · Mar 14, 2018

There is a problem alluded to by at least one poster, and it's not a small deal. Corrosion of the threaded 'keel bolt" (actually a J-shaped threaded rod embedded in the lead keel casting) takes place under the inside bilge where you see the nut and washer plate.
The part with oxygen-starved water where the corrosion takes place is under that. What you want, if you have a choice, is NO sealant on top of those nuts and washers, just to make it easy to see any leak from outside. And, last thing you want is trapped water under the nuts.
It is pretty normal to drop, inspect, and re-bed an external ballast keel after X number of decades. Some boats and models have more history of leakage than do others.
If you are shopping a boat with some sort of cosmetic inside "sealant" over the keel bolts, both you and the surveyor will want to factor in a re-bed in the yard as part of the purchase.
Note that designers and builders calculate a LOT of safety factory in their keel attachment scheme; which is why you seldom see stories of keels detaching from production boats. Just remember, "seldom" is not the same as "zero".

So, do not get totally extra-anxious, but do not put off the keel re-bed too long, either.