Socket for tightening keel bolts

[Noah]

I made a comment/observation earlier in this thread about possible oxygen starvation and rusty keel bolt washers. I looked back and guess what? I picked up that tidbit from John Langford on this forum. Still no other confirmation. But worth consideration anyway:
http://c34.org/bbs/index.php/topic,8325.msg58638.html#msg58638

[Breakin Away]

I did not realize that Catalina finished the bilge with gelcoat. I thought it was just paint over top the fiberglass layup. I also did not realize that they would do this after the washers and nuts were tightened onto the keel bolts. I sort of thought that they would finish all fiberglass work in the keel sump first, then bolt on the keel.

I don't really see any signs of gelcoat on top of my washers.

The washer for my front-most keel bolt has some brown rust on it, but the washer can't be removed because of interference from the drain scupper that sticks out over it. I tried some CLR on it, but the best I could do was to go in with a toilet brush, and the CLR did not take much off. I can barely squeeze my hand down there (but getting it out is real rough on my skin), so I might be able to get some sandpaper on it. I could also lift the washer up partway to dry underneath it and possibly apply some bedding compound.

So to return to my question, is there any perceived benefit to drying the area around the bolts and under the washers, then applying some bedding (perhaps MainSail's butyl) to keep water out of the crevices? Any reason why this would be a bad idea?

[Jon W]

Have you tried FSR from Davis?

[Indian Falls]

The only place you find this topic of "oxy starvation" corrosion of SS is in sailing forums... I'm very skeptical of this old wives tale concerning rusting of SS since oxidation can only occur in the presence of Oxygen.  Opposite of this I have cheap low quality stainless cutlery that rusts in the dishwasher. If  you look elsewhere (not in a sailing forum) for this topic you'll find this at the McNally Institute:

"The basic {corrosion} resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface. This coating is a "passive" film which resists further "oxidation" or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids THAT CONTAIN OXYGEN. Once the layer has formed, we say that the metal has become "passivated" and the oxidation or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. per year).

Unlike aluminum or silver this passive film is invisible in stainless steel. It's created when oxygen combines with the chrome in the stainless to form chrome oxide which is more commonly called "ceramic". This protective oxide or ceramic coating is common to most corrosion resistant materials.

Halogen salts, especially chlorides easily penetrate this passive film and will allow corrosive attack to occur. The halogens are easy to recognize because they end in the letters "ine". Listed in order of their activity they are:

    fluorine
    chlorine
    bromine
    iodine
    astatine (very unstable.)

These are the same chemicals that will penetrate Teflon and cause trouble with Teflon coated or encapsulated o-rings and/ or similar coated materials. Chlorides are one of the most common elements in nature and if that isn't bad enough, they're also soluble, active ions; the basis for good electrolytes, the best conditions for corrosion or chemical attack."

There is more on the subject debunking O2 starvation corrosion here:  http://www.estainlesssteel.com/corrosion.shtml   

It would appear that the two things very common in boats are chlorine and salt  which make far more sense than O2 starvation. 

Why aren't all the properly bedded keels falling off left and right if lack of O2 at the keel bolts is eating them away?   I'm certain there could be a situation where one of the aforementioned chemicals permanently appears in an o2 free environment where the stainless can't repair itself. 

I hope everyone finds this interesting.

[Breakin Away]

To return to my question, is there any perceived benefit to drying the area around the bolts and under the washers, then applying some bedding (perhaps MainSail's butyl) to keep water and chloride ions out of the crevices? It might also provide enough lubrication to avoid scraping away the passivation layer. Both, taken together, might inhibit crevice corrosion.  Any reason why this would be a bad idea?

[KWKloeber]

Dan,

There's discussion of different forms of stainless corrosion and O2 starvation than just on sailing forums.  I'm not a metallurgical engineer, but it was my understanding that crevice corrosion (O2 starvation) was due to free oxygen not being available to form and/or repair the protective layer, and so then the presence of H20 (containing dissolved O2) results in corrosion.  ie, dissolved O2 (or combined H2O) cannot form or repair the protective layer.  This looks like a pretty good description (with excellent pics "describing" the reactions) from UA (apologies to those War Eagle fans.)
http://bama.ua.edu/~mweaver/courses/MTE271/22_MTE%20271_Corrosion.pdf

I think keels don'r fall off because 1) you're talking a huge mass of the bolt compared to maybe a small crack on a standing rigging swage that attacks its holding integrity.  Plus, if the bilge is dry, there's no dissolved O2 to get down to the thread.  When I dropped dropped my keel (due to water infiltration down the thread/attacking the keel bedding) was there surface rust on the bolts?  Yes.  Was it enough to cause any sleep loss?  Not a minute.

-kk

[KWKloeber]

To return to my question, is there any perceived benefit to drying the area around the bolts and under the washers, then applying some bedding (perhaps MainSail's butyl) to keep water and chloride ions out of the crevices? It might also provide enough lubrication to avoid scraping away the passivation layer. Both, taken together, might inhibit crevice corrosion.  Any reason why this would be a bad idea?

pics?

Is it serious corrosion (integrity of the fastener) or just some surface rust (cosmetic)? 
Unless it's dramatic, I'd be more concerned about unseen crevice corrosion in a standing rigging swage or on a clevis (every one one of which is critical), than surface rust on one washer on a (over-designed set of) keel bolts.

Yah nevah know the grade and more importantly the quality of OEM fasteners used, which may be the cause of or contributing to the corrosion.

-kk

[DaveBMusik]

If there was no "O" in "H2O" would it still be wet?     
Happy New Year!

[KWKloeber]

If there was no "O" in "H2O" would it still be wet?     
Happy New Year!

ABSOLUTELY!!  But unfortunately you won't hear the tree in the forest fall..

HNY all y'all.

[Indian Falls]

Ya'll know there are two steel lifting points cast into the lead on the top of the keel?
Are ya'll sure this rusty residue isn't from these?  Leaking the rusty red crap up through your keel bolt holes?
That's what I had.   I had rusty water running out of the smile on the hard and water coming up through the bolt holes every year until I re-bedded the keel.