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

Doug,
On all the lead keels that I have seen, the bolts are held in the keel by
anchors, because the lead is too soft for threads to hold. Very often a
frame is constructed of steel and the the bolt pattern in the frame is used
to drill the mounting holes in the floors for alighnment reasons. This frame
is then cast into the keel. Alternatively, a wooden frame is made to suspend
the bolts head down with large washers and then the keel is cast. In all
cases the bolts cannot be removed without recasting the keel. I suppose one
could use a threaded anchor, but I have not seen that.
Steve

"DSK" wrote in message
. ..
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

Steve Lusardi wrote:
Doug,
On all the lead keels that I have seen, the bolts are held in the keel by
anchors, because the lead is too soft for threads to hold.

Really? I suppose if you're casting a lead fin around bolts held in
place by some kind armature, maybe you're right.

In my experience, cast lead keels are alloyed with antimony, which makes
it take a thread very well. The place for the keelbolts are drilled &
tapped (using a jig), then the bolts put in.

I have also seen conventional bolts put up through the keel stub via
recesses molded into into the keel, the recesses are then filled with
putty. Then there's the technique (used in a couple of the lower priced
mass-produced boats of the early 1970s) of welding the keelbolts in a
'T' and casting them into the keel. The method you describe is sort of a
variation, I can easily believe it's done but haven't seen it myself.

Fresh Breezes- Doug King