I recently hauled my boat and after few days I noticed allarming
coloured streaks oozing out of the thin crack (very thin and of little
concern by itself) between the keel and the hull.
The colour of the streaks is green-blueish, something that suggests
copper sulfate, and sort of shiny that suggests micro-cristals.

According to the boat makers the keel bolts are AISI 316 SS and the keel
is of lead.
The boat was made in 1978.

Do you have any suggestion? Do I have to drop the keel and check the
bolts? I would rather avoid it, if not really necessary.

Thank you
Daniel

Daniel,
There have been a lot of discussions about using SS below the water line as
well as using SS with other metals in an electrolyte solution (salt water).
The arguments boil down to the susceptibility of SS corrosion. In the
absence of electrolysis, SS protects itself by using excess oxygen in its
environment to create a thin skin of corrosion, which prevents additional
corrosion. If abrasion through mechanical movement abrades the skin and
additional oxygen is available, it self heals. If the surrounding
environment is oxygen depleted because of the lack of air or water flow
around it and mechanical abrasion occurs, corrosion is very rapid and
severe. This is commonly called crevice corrosion. In addition to this is
electrolytic corrosion, the first mentioned case. This is where the
dissimilar metals in an electrolyte create an electric current which erodes
the most anodic metal at a rate according to their difference in the
periodic element table.

Now, in your case, you know nothing because you did not build it yourself.
You observe a staining which could be corrosion. You have been told your
keel is lead and the bolts are 316. You have the prime ingredients of both
corrosion cases. You have no peace of mind here without keel removal. Can
you afford the loss of the boat or possibly even the loss of life? Your
call.
Steve

"Daniel" wrote in message
...
I recently hauled my boat and after few days I noticed allarming coloured
streaks oozing out of the thin crack (very thin and of little concern by
itself) between the keel and the hull.
The colour of the streaks is green-blueish, something that suggests copper
sulfate, and sort of shiny that suggests micro-cristals.

According to the boat makers the keel bolts are AISI 316 SS and the keel
is of lead.
The boat was made in 1978.

Do you have any suggestion? Do I have to drop the keel and check the
bolts? I would rather avoid it, if not really necessary.

Thank you
Daniel

The one way to tell if there's a problem is to remove a couple of bolts.

"Daniel" wrote in message
...
I recently hauled my boat and after few days I noticed allarming
coloured streaks oozing out of the thin crack (very thin and of little
concern by itself) between the keel and the hull.
The colour of the streaks is green-blueish, something that suggests
copper sulfate, and sort of shiny that suggests micro-cristals.

According to the boat makers the keel bolts are AISI 316 SS and the keel
is of lead.
The boat was made in 1978.

Do you have any suggestion? Do I have to drop the keel and check the
bolts? I would rather avoid it, if not really necessary.

Thank you
Daniel

Jim,
Normally the keel bolts will be cast into the leadballast and are not
removable without recasting the keel. They will appear as long studs and
fasten thru the floors with nuts and washers.
Steve

"Jim Conlin" wrote in message
...
The one way to tell if there's a problem is to remove a couple of bolts.

"Daniel" wrote in message
...
I recently hauled my boat and after few days I noticed allarming
coloured streaks oozing out of the thin crack (very thin and of little
concern by itself) between the keel and the hull.
The colour of the streaks is green-blueish, something that suggests
copper sulfate, and sort of shiny that suggests micro-cristals.

According to the boat makers the keel bolts are AISI 316 SS and the keel
is of lead.
The boat was made in 1978.

Do you have any suggestion? Do I have to drop the keel and check the
bolts? I would rather avoid it, if not really necessary.

Thank you
Daniel

I've no idea if it's applicable to ss keel bolts in a lead keel, but it's
certainly possible to detect loss of bolt thickness caused by corrosion for
steel bolts in concrete foundations - as used in chair lifts, power wire
towers etc. Ring a few local non destructive testing companies, it's
reasonably specialised but you might find someone with the right equipment,
experience, and an interest in boats ...
Has to be better than taking off the keel!
David
"Steve Lusardi" wrote in message
...
Jim,
Normally the keel bolts will be cast into the leadballast and are not
removable without recasting the keel. They will appear as long studs and
fasten thru the floors with nuts and washers.
Steve

"Jim Conlin" wrote in message
...
The one way to tell if there's a problem is to remove a couple of bolts.

"Daniel" wrote in message
...
I recently hauled my boat and after few days I noticed allarming
coloured streaks oozing out of the thin crack (very thin and of little
concern by itself) between the keel and the hull.
The colour of the streaks is green-blueish, something that suggests
copper sulfate, and sort of shiny that suggests micro-cristals.

According to the boat makers the keel bolts are AISI 316 SS and the keel
is of lead.
The boat was made in 1978.

Do you have any suggestion? Do I have to drop the keel and check the
bolts? I would rather avoid it, if not really necessary.

Thank you
Daniel

Steve Lusardi wrote:
Jim,
Normally the keel bolts will be cast into the leadballast and are not
removable without recasting the keel. They will appear as long studs and
fasten thru the floors with nuts and washers.

They can be removed. That's what the threads do.

You might have a really tough time getting them to turn... if you put a
slugging wrench down onto the nut, then put on a lock nut over that, you
should be able to get it started.

DSK

"DSK" wrote in message
.. .
Steve Lusardi wrote:
Jim,
Normally the keel bolts will be cast into the leadballast and are not
removable without recasting the keel. They will appear as long studs and
fasten thru the floors with nuts and washers.

They can be removed. That's what the threads do.

I believe he means from the keel itself.

Steve

You might have a really tough time getting them to turn... if you put a
slugging wrench down onto the nut, then put on a lock nut over that, you
should be able to get it started.

DSK

They can be removed. That's what the threads do.


Steven J. Ross wrote:
I believe he means from the keel itself.


So did I


Regards
Doug King

They better not be able to be removed.
All keel builders either weld a cage, or J-hook the bottom of the
bolt to lock it in the lead. Only older iron keel are not done this way.
There was a few cases of keels falling of because the forgot to bend the
bottom of the bolt. The lead/antimony will not hold a straight bolt.
Most keel builders tack the bottoms together to prevent them from floating
away during the lead pour.

"DSK" wrote in message
.. .
Steve Lusardi wrote:
Jim,
Normally the keel bolts will be cast into the leadballast and are not
removable without recasting the keel. They will appear as long studs and
fasten thru the floors with nuts and washers.

They can be removed. That's what the threads do.

You might have a really tough time getting them to turn... if you put a
slugging wrench down onto the nut, then put on a lock nut over that, you
should be able to get it started.

DSK

Daniel,
If you decide to remove the keel and inspect the bolts, I for one would be
very interested in their state. I personally believe that malleable iron or
manganese bronze is the keel bolt of choice and that the use of SS is very
dangerous for the reasons stated in my other thread. However, there are many
others that don't feel this way. Your inspection could go a long way in
determining which school of thought is correct.
Steve

"Daniel" wrote in message
...
I recently hauled my boat and after few days I noticed allarming coloured
streaks oozing out of the thin crack (very thin and of little concern by
itself) between the keel and the hull.
The colour of the streaks is green-blueish, something that suggests copper
sulfate, and sort of shiny that suggests micro-cristals.

According to the boat makers the keel bolts are AISI 316 SS and the keel
is of lead.
The boat was made in 1978.

Do you have any suggestion? Do I have to drop the keel and check the
bolts? I would rather avoid it, if not really necessary.

Thank you
Daniel