On Sat, 29 Jan 2011 22:50:57 -0600, CaveLamb
wrote:

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. Hope the stub wasn't hard to get out.

Stan


Thanks, Stan.

No, It came out with finger power and a long socket.
Just getting the socket on it was the hard part.

I can't inspect what's in the hole until I can remove the stanchions
completely and dig out all the old sealant.

What kind of "beeswax/pitch mixture" would that be?

Like you already know *everything* on a sal****er boats corrodes and
breaks. Good sealant really helps, we use tubes and tubes of that
white silicone sealant from the Marine boat supply. I'll get the name
if you need it.

I've seen pics of your boat. You got life easy. I waste my windy days
working on a 20 year old commercial fishing boat.