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Daniel
Guest
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 Posted: Tue May 24, 2005 3:03 pm Post subject: keel bolts |
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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 |
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Steve Lusardi
Guest
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| Posted: Tue May 24, 2005 8:03 pm Post subject: Re: keel bolts |
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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" <daniele.fua@unimib.it> wrote in message
news:l7Hke.24543$795.759388@twister1.libero.it...
| Quote: | 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 |
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Jim Conlin
Guest
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| Posted: Wed May 25, 2005 5:03 am Post subject: Re: keel bolts |
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The one way to tell if there's a problem is to remove a couple of bolts.
"Daniel" <daniele.fua@unimib.it> wrote in message
news:l7Hke.24543$795.759388@twister1.libero.it...
| Quote: | 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 |
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Steve Lusardi
Guest
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| Posted: Wed May 25, 2005 6:02 am Post subject: Re: keel bolts |
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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" <conlin@comcast.net> wrote in message
news:0MKdnRZtVJAEZg7fRVn-gw@comcast.com...
| Quote: | The one way to tell if there's a problem is to remove a couple of bolts.
"Daniel" <daniele.fua@unimib.it> wrote in message
news:l7Hke.24543$795.759388@twister1.libero.it...
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
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David Flew
Guest
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| Posted: Wed May 25, 2005 10:01 am Post subject: Re: keel bolts |
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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" <stevenospam@lusardi.de> wrote in message
news:d713kc$1so$02$1@news.t-online.com...
| Quote: | 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" <conlin@comcast.net> wrote in message
news:0MKdnRZtVJAEZg7fRVn-gw@comcast.com...
The one way to tell if there's a problem is to remove a couple of bolts.
"Daniel" <daniele.fua@unimib.it> wrote in message
news:l7Hke.24543$795.759388@twister1.libero.it...
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
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DSK
Guest
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| Posted: Wed May 25, 2005 2:04 pm Post subject: Re: keel bolts |
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Steve Lusardi wrote:
| Quote: | 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 |
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Steven J. Ross
Guest
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| Posted: Wed May 25, 2005 4:05 pm Post subject: Re: keel bolts |
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"DSK" <dsk@dontbotherme.com> wrote in message
news:6g%ke.20287$8S5.9853@bignews3.bellsouth.net...
| Quote: | Steve Lusardi wrote:
Jim,
Normally the keel bolts will be cast into the leadballast and are not
removable without recasting the keel. They will appear as long studs and
fasten thru the floors with nuts and washers.
They can be removed. That's what the threads do.
|
I believe he means from the keel itself.
:) Steve
| Quote: | You might have a really tough time getting them to turn... if you put a
slugging wrench down onto the nut, then put on a lock nut over that, you
should be able to get it started.
DSK
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DSK
Guest
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| Posted: Wed May 25, 2005 5:04 pm Post subject: Re: keel bolts |
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| Quote: | They can be removed. That's what the threads do.
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Steven J. Ross wrote:
| Quote: | I believe he means from the keel itself.
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So did I
;)
Regards
Doug King |
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Steve Lusardi
Guest
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| Posted: Wed May 25, 2005 7:03 pm Post subject: Re: keel bolts |
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Doug,
On all the lead keels that I have seen, the bolts are held in the keel by
anchors, because the lead is too soft for threads to hold. Very often a
frame is constructed of steel and the the bolt pattern in the frame is used
to drill the mounting holes in the floors for alighnment reasons. This frame
is then cast into the keel. Alternatively, a wooden frame is made to suspend
the bolts head down with large washers and then the keel is cast. In all
cases the bolts cannot be removed without recasting the keel. I suppose one
could use a threaded anchor, but I have not seen that.
Steve
"DSK" <dsk@dontbotherme.com> wrote in message
news:9o1le.28087$CR5.17414@bignews1.bellsouth.net...
| Quote: | 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
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DSK
Guest
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| Posted: Wed May 25, 2005 10:04 pm Post subject: Re: keel bolts |
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Steve Lusardi wrote:
| Quote: | 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 |
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littlewing1
Guest
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| Posted: Thu May 26, 2005 2:02 am Post subject: Re: keel bolts |
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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" <dsk@dontbotherme.com> wrote in message
news:6g%ke.20287$8S5.9853@bignews3.bellsouth.net...
| Quote: | 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
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Terry Spragg
Guest
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| Posted: Thu May 26, 2005 4:02 am Post subject: Re: keel bolts |
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DSK wrote:
| Quote: | 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 |
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Steve Lusardi
Guest
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| Posted: Thu May 26, 2005 7:01 am Post subject: Re: keel bolts |
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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" <daniele.fua@unimib.it> wrote in message
news:l7Hke.24543$795.759388@twister1.libero.it...
| Quote: | 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 |
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Guest
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| Posted: Thu May 26, 2005 9:04 am Post subject: Re: keel bolts |
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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. *** 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. |
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Brian Whatcott
Guest
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| Posted: Thu May 26, 2005 1:02 pm Post subject: Re: keel bolts |
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On Thu, 26 May 2005 00:41:47 -0300, Terry Spragg
<tspragg567nospam@rogers.com> wrote:
| Quote: | 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
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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 |
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