Hi David,
My quip was not quick enough to get in before
your clarification and at the same time, too
quick. This subject is not too deep for me after all.
Re:
1) - so, you were motoring or sailing downwind
through at an extremely low tide?
2) - I would chase each of the cracks with a
burr, not a disk grinder. A disk grinder will not
reveal the crack in the same manner as a burr
since it can fold over clean material and you think it doesn't go any further.
My favourite burr looks like the "pointed tree" SG, on this page:
http://www.boggstool.com/page2.html
- when the cracks have been hogged out to bright
metal (you cannot see the crack anymore), you can
fill & fair with epoxy filler and tape as per
recommendations. Remember to apply epoxy to lead
on a freshly exposed surface only, as it starts
to oxidize right away. A quick run over
everything with a wire brush should do the trick.
- if you excavate down to the keel bolt, don't
panic! clean way some more and pre-treat with
phosphoric acid (and wait 24 hours) to "kill the
rust" around your S/S keelbolt before proceeding with above.
- this repair assumes the keel-hull joint is
tight, otherwise crevice corrosion can still
occur since source is a different path.
- I am skeptical that these cracks are due to
haulout on a railway. Lead is such a ductile
material that a point load stress at the bottom
is not resolved as a stress crack at a location
that has a much greater area of support. I
believe the indications should be near the bottom of the keel if this case.
Cheers, Russ
Sweet 35 mk-1
PSW, east Vancouver island
At 07:26 PM 03/10/2014, you wrote:
Two related issues:
1) I found an uncharted rock at low tide
this summer so am now having a mast out/keel off
repair by a reputable yard near Sidney, BC.
Since my draft is slightly more than the 2
meters Canadian Hydrographic set as their
minimum for charting obstructions I guess they are off the hook.
2) However the keel has shown minor
weeping from a spot on the port side
corresponding to about the lower end of a keel
bolt - seen at haul outs since purchase about 6
years ago. At least two surveyors have seen it
and ignored it. Usually there is a teaspoon or
two of water and a bit of rust seeps out over 24
hours or so. This time there are two
spots. While removing the keel (as per #1
above) light grinding over the area shows a fine
vertical crack a couple of inches long and a
couple more smaller cracks on other spots
further back in line with bolts. On this thin
keel the aft bolt is only about ½ diameter. I
had been told earlier at a Rendevous that the
trickle, etc could be caused by impurities in
the scrap lead used by Mars originally. At
purchase and since then there has been noted a
very slight cant to starboard over the whole
keel (maybe ¾ at most) again noted but ignored at surveys.
The yard is telling me several things and I am
interested to know if anyone else with this keel
has seen similar issues. Among the suggestions I
have heard by the yard so far: do light grinding
of the area then prep and patch with mat/epoxy
to seal; or do the patch and also an overlay of
fibreglass to give more strength (neither of
which would be guaranteed); or consider a new
keel(!). They seem certain the cracking is
stress on the keel compounded by annual hauling
at our Club marine railway for yearly bottom
prep, etc; theyve also indicated they would
contact Mars for advice. My concern is that none
of the suggestions sound like a final solution
if they are correct in the analysis and
reasoning. There are also concerns re crevice
corrosion in the long term in any event.
So: If anyone has heard of and or dealt similar
issues Id appreciate feedback. I hope to
contact Rob at Southshore as he had the original
information that scrap lead used in that era was
the culprit and essentially a cosmetic issue.
Thanks folks. List advice is a great asset.
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