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