keel bolts
 

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

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

DSK wrote:
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


If the bolts were bent and cast into the molten keel, you will not
remove them. You should find out the breaking strength of the bolts
and then do not exceed this torque when trying to remove the nuts or
bolts. If you get up close to breaking torque for your bolts and
they don't come out and they don't break they are ok. Hell, If they
get up to 75% and don't give, I'd trust them.

If you break one, you've got to do them all.

If they need to be changed, you might cut them out with a torch or
saw, and re solder the keel top sections around the replacements,
which you will position with very carefully crafted jigs tack
soldered on, then cut off afterwards.

Should keep you busy for the weekend. Older bodymen and plumbers
have experience with lead filling, using a naptha blowtorch. Old
cast iron pipes were often caulked with molten lead.

Good luck

Terry K

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

Hi

Is the sound sound when you knock on the top of the bolts with a
hammer, do they all response with the same sound ?
Lead and ss with no deforming of the wood , with no black water with no
strange coloring of the wood around --- well I guess that the lead
protected the ss well , --- one are in the plus and the other in the
minus end of metal catalys ability ,acturly the lead would protect the
rods , in such cases what you realy shuld look at is the nuts not the
rods.
---------- If there are any corosion there will be miscolored wood not
just a profe that the seames are well copper sulfated , there shuld be
a huge quantity of iron salts , are there ? If there are any corrosion
you will hear it instantly as bolts corode in different stated , one be
good another almost gone they will respond with a click or a knock
depending how much material left. Damn plain steel bolts been lasting a
century , this is even ss progerly a place where the only metal near
by, are one that acturly protect the rods.
Listen to them look if there are any dameage on the wood ,if huge
amounts of iron salts are miscoloring the wood ---.
Don't repair it if it's not broken.
P.C.

On Thu, 26 May 2005 00:41:47 -0300, Terry Spragg
wrote:


If the bolts were bent and cast into the molten keel, you will not
remove them. You should find out the breaking strength of the bolts
and then do not exceed this torque when trying to remove the nuts or
bolts. If you get up close to breaking torque for your bolts and
they don't come out and they don't break they are ok. Hell, If they
get up to 75% and don't give, I'd trust them.
///
Terry K

This certainly sounds like uncommonly good advice.
Unfortunately, it is not practical - something of a day dream in fact.

Engineers find great difficulty in relating tightening torque on a
well-characterized fresh nut and bolt to its allowables or breaking
strength - but when it comes to a submerged, possibly corroded
fastener, you will be hard pressed to compute a torque value that is
within a factor of three of the actual value which snaps the shank.

Brian Whatcott Altus, OK

Brian Whatcott wrote:

On Thu, 26 May 2005 00:41:47 -0300, Terry Spragg
wrote:



If the bolts were bent and cast into the molten keel, you will not
remove them. You should find out the breaking strength of the bolts
and then do not exceed this torque when trying to remove the nuts or
bolts. If you get up close to breaking torque for your bolts and
they don't come out and they don't break they are ok. Hell, If they
get up to 75% and don't give, I'd trust them.

///

Terry K


This certainly sounds like uncommonly good advice.
Unfortunately, it is not practical - something of a day dream in fact.

Engineers find great difficulty in relating tightening torque on a
well-characterized fresh nut and bolt to its allowables or breaking
strength - but when it comes to a submerged, possibly corroded
fastener, you will be hard pressed to compute a torque value that is
within a factor of three of the actual value which snaps the shank.

Brian Whatcott Altus, OK

Well, let's presume a non-corroded bolt, then. If it breaks, it was
corroded. Surely, the fact that it is submerged doesn't matter much.

I know little about this but I do have a couple of suggestions.
Perhaps try to cut the lead out from around the top of one boltat the
joint to allow inspection. If it is good, just make a sheet metal dam
and pour in molten lead.
Maybe put in additional bolts. This involves drilling a large diameter
hole deep into the lead and an access hole from the side, putting in a
long threaded rod and putting two nuts with a large washer on the
threaded rod via the access hole. Then you fill the access hole with
some lead and epoxy and pour lead down around the threaded rod. I
believe I got this idea from Practical Sailor who discussed this same
topic once.
What could these green corrosion products possible be? Are the bolts
really SS? Check the tops of the bolts. If they are SS what could
this material be? Look into SS corrosion and then in the CRC Handbook
to see what the possible products look like.

Is it possible the builder put a copper sheet between the keel and hull
for some reason?

Your problem got me curious so I did a search on keel bolts and there
is a plethora of info on the subject of inspecting and replacing keel
bolts. Owning a 28' boat, I have never had this problem because my
ballast is internal to the hull of my S2. Considering the difficulties
with bolt-on keels, why do they seem favored over good internal
ballast?
Now I cant stop and will become obsessed with finding a way to inspect
keel bolts...

Daniel wrote:
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

Thankyou for all your kind replies.
Just to add a little more information:
1) the hull is fiberglass
2) still according to the manifacturer, the bolts are fixed in the lower
part with a washer and a nut embedded in the keel lead. It should be
possible to unfasten them.

I agree with dbohara: the colour of the ooze is quite puzzling: SS 316,
fiberglass, lead... where do copper cristals come from?

Anyway, my first try is going to be some inspection in the crack; this
weekend I will chisel off the outer layers of paint, putty end whatelse
on a limited zone to have a closer look at the interface between the
keel and the hull.

I'll keep you posted.

Daniel

The ballast would be much safer if it were well up in the middle of the
boat.


wrote in message
oups.com...
Your problem got me curious so I did a search on keel bolts and there
is a plethora of info on the subject of inspecting and replacing keel
bolts. Owning a 28' boat, I have never had this problem because my
ballast is internal to the hull of my S2. Considering the difficulties
with bolt-on keels, why do they seem favored over good internal
ballast?
Now I cant stop and will become obsessed with finding a way to inspect
keel bolts...

Dan,
FWIW . . .

IF it were MY boat, and this critical of a structure {with regard to the
results of a catastrophic failure}. . . I literally wouldn't trust MY eyes,
library research, and any non-viewers comments.

This may be one of those cases where the few dollars to hire a TRUE expert,
would be well spent. I would do a bit of research and find a GOOD, WELL
RECOMMENDED, local sailboat surveyor. Hire his expertise, and listen to his
opinion.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

"Daniel" wrote in message
...
Daniel wrote:
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.
SNIP

Manganese bronze is not a good choice for underwater. Silicon bronze is far
more stable.

If you wanted to keep the ballast really safe from sand bars and
reefs, you could just run it up the mast and hand it next to the sails
where it could be easily inspected from the deck!


BTW this IS sarcasm.
On Sat, 28 May 2005 00:59:18 -0400, "Jim Conlin"
wrote:

The ballast would be much safer if it were well up in the middle of the
boat.


wrote in message
roups.com...
Your problem got me curious so I did a search on keel bolts and there
is a plethora of info on the subject of inspecting and replacing keel
bolts. Owning a 28' boat, I have never had this problem because my
ballast is internal to the hull of my S2. Considering the difficulties
with bolt-on keels, why do they seem favored over good internal
ballast?
Now I cant stop and will become obsessed with finding a way to inspect
keel bolts...

Daniel,
If it is copper, it must be coming from somewhere. Does it leave a
green trail when a fragment is held in a torch flame? (Some lighters
are hot enough to get this effect.) Some ablative bottom paints use
copper to repel clingy living things. There might also be some copper
tube or pipe close enough to your boat that it can contribute like an
anode. It is possible that you have a stray current either within
your own boats grounding bond to the water, or with the surrounding
dock or other structure. The copper crystals could be formed like
those on a cathode in an aquious solution where copper is present.
The copper could be a seroius warning. Don't stop 'till you know
where it came from.
Good luck.
On Fri, 27 May 2005 08:20:26 GMT, Daniel
wrote:

Daniel wrote:
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

Thankyou for all your kind replies.
Just to add a little more information:
1) the hull is fiberglass
2) still according to the manifacturer, the bolts are fixed in the lower
part with a washer and a nut embedded in the keel lead. It should be
possible to unfasten them.

I agree with dbohara: the colour of the ooze is quite puzzling: SS 316,
fiberglass, lead... where do copper cristals come from?

Anyway, my first try is going to be some inspection in the crack; this
weekend I will chisel off the outer layers of paint, putty end whatelse
on a limited zone to have a closer look at the interface between the
keel and the hull.

I'll keep you posted.

Daniel