Comments interspersed.


"matt colie" wrote in message ...
Please do tell us -Oh (self ascribed) Great One

A. How can a mortal human determine that tubular spreader that has been
adequate to the purpose for eleven seasons is about to buckle in a long
column type failure when the conditions had lightened in the last two
hours?

Are you sure the spreader tube was the cause? I doubt it myself.
Not being there I'm just guessing but I'd find it hard to believe
there could be enough stress on the spreader to break it if there
were not something else that let loose first.

B. How (thirty-plus years ago - no portable ultrasonic inspection
available) does one assess the soundness of a twenty year old
formaldehyde-resorcinol joint that was closely examined as the owner had
sanded and varnished the spar three weeks before that day??

One gets rid of wooden junk after that many years. It should
have been replaced with an aluminum spar long ago. Wooden
spars, like standing rigging don't last forever. To be safe
replace wooden spars every ten to fifteen years.

C. How does a common citizen determine that there is an invisible crack
at the bottom of a finishing mark that has caused fatigue embrittlement
to an otherwise nice looking 316 stainless strap?

There are dyes available for this purpose.

This boat's
chainplates were later inspected by a professor of metallurgy in his lab
at a near-by well known university. I quote “We didn’t stand a chance.”
The professor had been on the helm at the time and was the person injured.

You should have checked them more closely
before they failed. Maybe if you had removed them
and sent them to the same lab prior to the time they
failed you could have gotten the news in time to do
something about it before the failure.

You are not totally to blame because the chainplates
were not made thick enough to begin with or they
would not have fatigued and failed. That should be
a little consolation to you.My chainplates are 3/16"
thick and 1-3/4" wide. They are as strong as the
day they were installed. You could lift the whole
boat with them.

S.Simon

Did you know this?;

"Simple Simon" wrote in message
...

One gets rid of wooden junk after that many years. It should
have been replaced with an aluminum spar long ago. Wooden
spars, like standing rigging don't last forever. To be safe
replace wooden spars every ten to fifteen years.

Simple Simon wrote:
and My responses to his
Comments interspersed.
As required


"matt colie" wrote in message ...

Please do tell us -Oh (self ascribed) Great One

A. How can a mortal human determine that tubular spreader that has been
adequate to the purpose for eleven seasons is about to buckle in a long
column type failure when the conditions had lightened in the last two
hours?


Are you sure the spreader tube was the cause? I doubt it myself.
Not being there I'm just guessing but I'd find it hard to believe
there could be enough stress on the spreader to break it if there
were not something else that let loose first.

=Most of the rig was still aboard, we were able to recover the upper
mast, the genoa, head and back stays from the shallow water as we had
tied a cushion to a spinnaker halyard. Nothing was broken or loose.
The failed spreader was a picture of classic long column buckling
failure. Why it chose then, we could not determine.

B. How (thirty-plus years ago - no portable ultrasonic inspection
available) does one assess the soundness of a twenty year old
formaldehyde-resorcinol joint that was closely examined as the owner had
sanded and varnished the spar three weeks before that day??


One gets rid of wooden junk after that many years. It should
have been replaced with an aluminum spar long ago. Wooden
spars, like standing rigging don't last forever. To be safe
replace wooden spars every ten to fifteen years.

=There are a whole lot of people that disagree with you here. If this
is actually your opinion, I suggest very strongly that you not voice it
in the hearing of any of the conservators of classic boats and yachts.
There are a goodly number of built-up section masts that are still in
service and I know for a fact that the owner’s don’t share your opinion
about this. I’m going to have a thirty five year old mast in my shop
this winter so the owner can refinish it.

Even the early larger glass boat were often delivered with wood spars as
extruded section of adequate size were not yet available.

C. How does a common citizen determine that there is an invisible crack

at the bottom of a finishing mark that has caused fatigue embrittlement
to an otherwise nice looking 316 stainless strap?


There are dyes available for this purpose.

=Dye penetrants are very difficult to evaluate on surfaces that are not
smooth. Penetrants will not reliably indicate a discontinuity as small
as the instigator probably was (based on the surviving parts)
How does a dye detect an embrittlement. This is a change of the
materials physical properties and was only detected by microscopic
evaluation and microprobing the local hardness of the sectioned and
polished parts.


This boat's
chainplates were later inspected by a professor of metallurgy in his lab
at a near-by well known university. I quote “We didn’t stand a chance.”
The professor had been on the helm at the time and was the person injured.


You should have checked them more closely
before they failed. Maybe if you had removed them
and sent them to the same lab prior to the time they
failed you could have gotten the news in time to do
something about it before the failure.

=The analysis that finally gave the definitive answer was destructive.
(No - eddy current was not conclusive either.) The cost of the
analysis (if billed at the labs standard rates) would have been in
excess of 1000$us in 1975 dollars, but as it was the helmsman’s lab....
(Hey - the guy got his arm busted - he wanted to know why.)

You are not totally to blame because the chainplates
were not made thick enough to begin with or they
would not have fatigued and failed. That should be
a little consolation to you.My chainplates are 3/16"
thick and 1-3/4" wide. They are as strong as the
day they were installed. You could lift the whole
boat with them.

S.Simon

=Most of the 3 and 400 series stainlesses are relatively fatigue prone.
That is why standing rigging has a limited life.
=Have you removed said chainplates for proper inspection?

=This was a 40 foot boat, and the chainplates were 3/8 thick and about
2" wide. The replacements were made with a polished surface even though
this makes them more susceptible to face wear by the turnbuckles.


Matt Colie - See prior sig