What is this protective covering on my keel bolts?

[Skipper Bob]

Firstly, there is no issue of leaks in or from the keel. The corrosion of the keel bolts is from standing water in the bilge.

Next, the designer kindly supplied me with the keel's design drawing (dated Jan. 1964), in which the keel bolts are clearly visible. At the bottom they are recessed in a 25mm deep cavity, which itself is 50mm wide. The bolts then pass all the way through the keel (650mm high) to the top where they exit and stick out by 70mm. The design drawing states:

Cast in the keel are 6 steel pipes, for the 6 keel bolts diameter 1". The keel bolts diameter 1/2" and diameter 3/4" are screwed into the keel.

and:

Keel bolts to be of suitable material (U.T.S. not less than 14 T/in2) and to be hardened up on large diameter washers as section 25 of the rules.

I should add that there are in total 8 keel bolts: the forward one is 3/4" thick, the aft one is 1/2" thick, the 6 others are 1" thick. The keel itself is cast iron. If I'm reading this right it would actually seem quite easy to drop each of the middle 6 keel bolts (720mm long) out by undoing their nut at the top (and opening up the fibreglass at the bottom of the keel), since they pass through pipes in the keel (if indeed they do).

It looks like I should sail to the nearest shipyard (in Hong Kong, 60nm away), slip the boat, remove one of the long keel bolts to confirm that it can indeed be removed as easily as the design drawing suggests, and then source new keel bolts, to replace all 6 of them.

Question: what material should I use? A quick read-up on the web suggests not to use stainless steel (as it is susceptible to galvanic corrosion), and recommends silicon bronze or monel. Which one should I go for and why?

[reed1v]

If they do drift through the keel, then you should be in good shape to pound them out. Impressed with that design since most builders just lag the bolts into but not through the keel(cheaper that way).

Replacement: silicone bronze or monel. Either will not set up corrosion and are very durable. They can also withstand the constant minor flex they will experience as the keel moves(yes, the keel will move ever so much, so will the hull).

Never, never, never use stainless steel. Its brittle, corrodes(crevasse and stress corrosion), does poorly in an oxygen depleted environment, and sets up a galvanic event between it and the iron.

Some folks with more money than common sense have used titanium, but have no personal experience with the metal.

[Skipper Bob]

Yes, van de Stadt seems to have done a proper job, more than half a century ago. Or perhaps that was how things were done back then...

Now, the next challenge will likely be sourcing those bolts in Hong Kong!

[reed1v]

Originally Posted by Skipper Bob

Yes, van de Stadt seems to have done a proper job, more than half a century ago. Or perhaps that was how things were done back then...

Now, the next challenge will likely be sourcing those bolts in Hong Kong!

There are a number of metal fabricating yards in HK. You could also ask Cheoy Lee if they can machine what you need, or give you references to fabricators who can. Big problem will be ensuring the parts are made according to specs.

This is when one misses old Subic naval base. A lot of American cruisers use to get their metals fabricated at its huge machine shop. Usually done as a courtesy: of course off the books. Maybe if you know someone in the Chinese navy?

[Skipper Bob]

reed1v, thanks for the tips! I’ll be in touch with them, and I assume my boat yard will also have several contacts. Unfortunately I don’t have any connections to the Chinese navy. They are not too popular around here - drive like they own the right of way.

[HappyMdRSailor]

Bob,

Sounds like you are on the right path.... These nuts/bolts/ and washers look frighteningly close to their "unintended end of service life" Don't let it drop off the radar...

[Franziska]

Just a thought.

If you can not remove the old bolts. Could you leave them alone and add some additional ones?
Maybe together with the idea of adding extra floors.

It's a big operation too, but sometimes it's easier to walk around an issue than to fix the initial one.

Obviously depends on the exact situation, size of the flange and more.

Good luck!

www.ladyrover.jimdo.com

[reed1v]

Originally Posted by Skipper Bob

reed1v, thanks for the tips! I’ll be in touch with them, and I assume my boat yard will also have several contacts. Unfortunately I don’t have any connections to the Chinese navy. They are not too popular around here - drive like they own the right of way.

Can imagine they are not popular with the locals. The HK Cantonese look down on the northern Mandarins as clods in any case. Have not been back there since the handover. Was a member of the RHKYC, and at the time members were worried the "northerners" would kick them out of their location. The Chinese did parade their goofy soldiers into HK right after the handover but quickly removed them when the rich and powerful tactfully suggested the Chinese were about to kill off the golden egg.

Worship of money is the supreme meaning of life down there. Which actually is a good thing for getting business done in the place.

[HappyMdRSailor]

Originally Posted by Franziska

Just a thought.

If you can not remove the old bolts. Could you leave them alone and add some additional ones?
Maybe together with the idea of adding extra floors.

It's a big operation too, but sometimes it's easier to walk around an issue than to fix the initial one.

Obviously depends on the exact situation, size of the flange and more.

Good luck!

Welcome to the Woods Mira 35 - Catamaran Lady Rovers Website!

Heya Franziska,

It's called "sistering" and it's very common... Excellent point to bring up here as nobody else has!

By the way... You sure seem to know quite a bit judging from all of your posts...

[HappyMdRSailor]

And just so everybody knows... I found the same "protective keel bolt coating" on the underside of the seal for my furler bearing... Lucky Me !

[reed1v]

Originally Posted by HappyMdRSailor

Heya Franziska,

It's called "sistering" and it's very common... Excellent point to bring up here as nobody else has!

By the way... You sure seem to know quite a bit judging from all of your posts...

Sistering of ribs, yes; of keel bolts, no. Put in enough holes and you hit another problem. Wctw, just drill out the old bolts and re thread.

[HappyMdRSailor]

Originally Posted by reed1v

Sistering of ribs, yes; of keel bolts, no. Put in enough holes and you hit another problem. Wctw, just drill out the old bolts and re thread.

Replacement is the best way to go, but it is a successful alternative that's been done many... many... many times...

[Marqus]

Originally Posted by reed1v

... just drill out the old bolts and re thread.

I'm just imagining the practicalities of drilling out rusted-in keel bolts. Let's assume a set of 8 such bolts that are 5/8-inch in diameter and 5 foot long.

Doesn't sound like you'd want to do that with a normal hand-held drill and drill bits. If not, what sort of drilling equipment would be employed and would it be necessary to drop and move the keel?

[Franziska]

And if the old ones would happen to be stainless... you'd end up drilling 'til hell freezes over (possibly twice!)

www.ladyrover.jimdo.com

[Marqus]

I was just thinking of conventional steel bolts - 5 foot per each seems like quite a job if there are 6 or 8 of them.

I'm sure there are ways and means, but drilling inside a sailboat cabin is never going to be easy. And even if you drop the keel, what equipment do you need.

Reed1v, can you (or anyone) give a clue as to how such drilling is routinely done?