In article
,
wrote:

On Jan 29, 7:59*pm, CaveLamb wrote:
I snapped a stanchion bolt the other day!
1/4" stainless steel machine screw actually.

Starboard stanchion by the cockpit. Forward inboard bolt.
The stanchions get abused sometimes, people grabbing them or the lifelines
while docking. *This one was leaning forward an inch off of vertical, but
seemed
sturdy enough.

I had the lifelines loose and was pulling on it (aft) - not all that hard!
to straighten it up - And something went POP! Pretty loud too

Inspecting it, it was pretty obvious what had happened, so I
dug the bolt out and replaced it.

This bolt (machine screw actually) had some serious corrosion issues.
(See the attached photos)

There is quite a bit of old damage on the mating surfaces.
That's the dull gray part.
And quite a bit of sealant over the old damage!

The bright metal tab seems to be the place where it broke.
There was NOT A LOT of metal there!

I have recently learned that there is an aluminum plate buried in the
deck lay-up where the stanchions are attached.

What say ye? *Was this 20 years of dissimilar metal corrosion?
(4 photos)http://www.home.earthlink.net/~capri26/bolt.htm

As soon as possible, ALL of the stanchions are going to be pulled and
re-bedded.

--

Richard Lamb
email me:
web site: *http://www.home.earthlink.net/~cavelamb

The aluminum would be the loser if it was electrolytic corrosion.
Probably chloride corrosion. Stainless steel -isn't-, at least when
it comes to sea water. You get inter-granular corrosion, basically
chunks fall out, how big depends on the alloy's grain structure. And
checking bolts would probably be a good idea, I'm told a beeswax-
pitch mixture makes a good goop for threaded hardware exposed to
seawater.

I read in a book on sailboat rigging that pure lanolin works well in
protecting splices in stranded stainless steel wire. They also
mentioned using pitch and beeswax, but lanolin was the best for inside
the splice.

Joe Gwinn