SS keel bolts, dees nuts?

[krisb007]

So I am in process of cleaning up my bilge area and one for the things on that list is to refresh the nuts and washers. This is a 70's model boat with SS studs in a lead keel. Studs look good but the nuts and washers are showing their age. What is the best choice for replacement? I know there are issues with SS on SS with galling. Would bronze nuts be a good option?

Let the beatings begin.....

[JPA Cate]

krisb007,

If the threads are clean and not dinged up, the nuts shouldn't gall going on. In what way are they showing their age? If it is just surface rust, clean them. (you can do it chemically, with oxalic acid, then rinse. If they show cracks, replace. 316 s/s is easily cleaned, and no, I don't think you'd gain anything from going to bronze, and you'd have to check about the dissimilar metals issues then.

Ann

[krisb007]

Originally Posted by JPA Cate

krisb007,

If the threads are clean and not dinged up, the nuts shouldn't gall going on. In what way are they showing their age? If it is just surface rust, clean them. (you can do it chemically, with oxalic acid, then rinse. If they show cracks, replace. 316 s/s is easily cleaned, and no, I don't think you'd gain anything from going to bronze, and you'd have to check about the dissimilar metals issues then.

Ann

I am mostly thinking of replacing the nuts because I need to replace the washers. Washers are heavily corroded but the nuts just mainly have surface rust.

[Cheechako]

Bronze should be OK ...but expensive. If the old are SS and lasted that long maybe good SS and use some lanokote or lanolin heavily on the threads would be a good idea. The lanolin will keep the water out of enclosed places like threads and prevent corrosion.

[Adelie]

I wouldn't mix materials. Use a water excluding grease like lanolin.

The question that follows replacement is how much to tighten the nut.

I replaced my keelbolts, nuts & washers (bolts not studs) and the Cal20 guru who sold them to me didn't answer the question.

Turns out there a lot of differing opinions on the matter even between manufacturers.

The thing that I think many miss is not what the capacity of the bolt is but that there is fiberglass in the bolt grip and damaging the glass by overtightening is distinctly possible, especially if well lubricated.

The tightening table I went with is the one from the J-24 association:
http://www.j24class.org/news/keel-bo...ance-bulletin/

[Lepke]

If you end up taking off the nuts, it might be worthwhile to remove a bolt and check for corrosion. Even 316 isn't perfect for salt water immersion.

[Terra Nova]

Originally Posted by Adelie

I wouldn't mix materials...

I wouldn't, either.

[roverhi]

Use 'Never Seize' on the threads and that will solve the galling issues. If the fastener is going to gall, makes no difference if the threads are clean and straight. Lanolin is a good corrosion preventer but a poor lubricant. Don't know how it would work as an anti-seize. Have had unlubricated SS parts seize and it was not a pleasant experience. It happened with almost no warning and ruined the pieces. Took two large wrenches with cheater bars and and two of us to unscrew the fitting. If it happened with a keel bolt would probably take a 'blue wrench' to get the nut off.

[Martkimwat]

It is interesting that a lot of people on here are saying don't mix metals which is normally true, but bronze and stainless are the exceptions as they have similar values on the metals nobility scale and the advantages of bronze are that it does not gall on stainless threads and does not suffer from crevice corrosion, which is why most quality bottle screws are actually chromed bronze on stainless threads or at least threaded bronze inserts. Having said that, I am surprised that the keel bolts are stainless rather than forged steel or even mild steel, due to its propensity for crevice corrosion. Keel bolts, with their high possibility of being immersed in stagnant water, are in an ideal environment to develop such corrosion. I would definitely try to draw the bolts and inspect them but it may be that they were cast into the keel mold using 'J' Bolts or some other captive head. Looking at the exposed part of the thread will tell you nothing, it is where the bolt is encircled and where water collects around it, becoming stagnant (starved of oxygen) that crevice corrosion has the ideal conditions to develop.