On Sat, 29 Jan 2011 20:59:31 -0600, 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.

I believe that I'd pull all the bolts and I'd use something other then
aluminum plate as a backer - I know, some of the commercial made
yachts use it - but I've used waterproof plywood epoxied in place and,
if I thought it necessary, capped with thin stainless plate, the
stanchion well bedded with 5200 and the new bolts well coated too. It
seems to last ands last. I'd also stop using all-thread (if that what
they were) bolts and get proper bolts (the kind that only have threads
where the nuts go :-) as they are stronger.

Another thing. Don't let people pull on the life lines when they get
on and off. I even made some lovely lanyards, tied to the hand rails,
with a crown knot and hung them over the lines for fat ladies to use
to haul themselves aboard.

Cheers,

Bruce