Chris wrote:
What specific signs of wear am I looking for in the swages of the
standing rigging? I check for any mechanical damage I can see,
especially cracks. Are there other things to look for?
There usually is slight surface rust on the stainless, which I scrub
off w/ WD40 to check for cracks.

Thanks!

Chris

Use a 8x loupe to inspect for cracks at the swages. You'll see them
much sooner. Check after scrubbing

Evan Gatehouse

John Cassara wrote:
Very Basic...........The dye gets trapped in the crack and causes the crack
to stand out better.


"Chris" wrote in message
oups.com...

So how does this dye test work?




But cables that have multiple strands will always look "failed"...
The dye gets trapped between the strands.

cavelamb wrote:
John Cassara wrote:
Very Basic...........The dye gets trapped in the crack and causes the crack
to stand out better.


"Chris" wrote in message
oups.com...

So how does this dye test work?




But cables that have multiple strands will always look "failed"...
The dye gets trapped between the strands.

I had thought the 20 yrear old rigging on my 28' S2 was good because it
had no sharp spots and seemed to look good with close visual
inspection. BUT, the mast was down and I had read an article in
"Seaworthy" about rigging inspection with a magnifier so I did this. I
was shocked to find cracks in ALL of the lower swages. At first they
were hard to find but soon I learned that they are almost always under
a small rusty looking spot which you remove with fine sandpaper.. All
the cracks ran lengthwise in the swages and were in the body of the
swages rather than at the edge where the wire goes in.
Being curious, I decided to do dye penetrant testing. This showed
absolutely nothing at all as the dye would not go into the cracks for
some reason. The cracks were clearly visible under a 10X loupe and
were real cracks.
I replaced all of the rigging and lifelines. That was close.

Thanks! That was exactly the information
and pointers I was looking for.

Chris


GBM wrote:
"Chris" wrote in message
oups.com...

So how does this dye test work?


Chris - You don't seem to be getting an answer to your question. Cracks in
welds etc are often better seen after treatment with a dye penetrant. This
is sometimes sprayed on. have a look at this Magnaflux web site then do your
own search. http://www.magnaflux.com/index.asp

I worked as a yacht rigger for many years. I consulted with metallurgical
engineers who also happened to be sailors. They said that by the time a dye
penetrant would help, it was too late! The problem is that the cracks start
from inside the swage and work their way outwards. We confirmed this by
cutting through swages that shows small external cracks and making a
polished section - There were many more cracks that were not visible but
which we could see under a powerful microscope. The cracks start at a
crevice where the swage has not fully surrounded a wire strand. At this
point, the stainless steel is under stress from swaging and there are often
chlorides present and a lack of oxygen. Apparently these are ideal
conditions for Chloride Stress cracking to occur.

We found that the only way we could delay cracking, was to seal the fitting
when we made the swage. We sometimes did this by adding a small amount of
epoxy to the wire near the end of the swage. The heat from the swaging
process caused the epoxy to run and fill all the voids and also make a neat
bead at the end of the swage. Others have used bees wax, nail polish and
other materials to seal the swages so as to keep the salt atmosphere out.

So far as inspection is concerned, we would clean up the swages using fine
emery paper or synthetic cleaning pads. We would then look at the fitting
through a strong magnifying glass. In particular, look at the edges of the
swage where the wire enters - that is where cracks often start.

Since there is really no good way to inspect, best solution is to replace
rigging on a regular basis - In freshwater, this may not be necessary - the
wire likely will fail first due to fatigue. In salt water, about every 7 to
10 years depending on temperature of area should be OK.

I have been out of the business for some time, so if anyone knows better,
please feel free to correct the above!

Hope this helps!

So the lower ones are more likely to derteriorate earlier, as
they are 'open' side up and in constant contact w/ sal****er
that can creep into any open caillary?
Good, they are much easier to check.


Evan Gatehouse wrote:
Chris wrote:
What specific signs of wear am I looking for in the swages of the
standing rigging? I check for any mechanical damage I can see,
especially cracks. Are there other things to look for?
There usually is slight surface rust on the stainless, which I scrub
off w/ WD40 to check for cracks.

Thanks!

Chris

Use a 8x loupe to inspect for cracks at the swages. You'll see them
much sooner. Check after scrubbing

Evan Gatehouse

GBM wrote:

quite well, actually.

Sorry for missing the OP's focus,
but I didn't miss your reply.

Chris - You don't seem to be getting an answer to your question. Cracks in
welds etc are often better seen after treatment with a dye penetrant. This
is sometimes sprayed on. have a look at this Magnaflux web site then do your
own search. http://www.magnaflux.com/index.asp

I worked as a yacht rigger for many years. I consulted with metallurgical
engineers who also happened to be sailors. They said that by the time a dye
penetrant would help, it was too late! The problem is that the cracks start
from inside the swage and work their way outwards. We confirmed this by
cutting through swages that shows small external cracks and making a
polished section - There were many more cracks that were not visible but
which we could see under a powerful microscope. The cracks start at a
crevice where the swage has not fully surrounded a wire strand. At this
point, the stainless steel is under stress from swaging and there are often
chlorides present and a lack of oxygen. Apparently these are ideal
conditions for Chloride Stress cracking to occur.

We found that the only way we could delay cracking, was to seal the fitting
when we made the swage. We sometimes did this by adding a small amount of
epoxy to the wire near the end of the swage. The heat from the swaging
process caused the epoxy to run and fill all the voids and also make a neat
bead at the end of the swage. Others have used bees wax, nail polish and
other materials to seal the swages so as to keep the salt atmosphere out.

So far as inspection is concerned, we would clean up the swages using fine
emery paper or synthetic cleaning pads. We would then look at the fitting
through a strong magnifying glass. In particular, look at the edges of the
swage where the wire enters - that is where cracks often start.

Since there is really no good way to inspect, best solution is to replace
rigging on a regular basis - In freshwater, this may not be necessary - the
wire likely will fail first due to fatigue. In salt water, about every 7 to
10 years depending on temperature of area should be OK.

I have been out of the business for some time, so if anyone knows better,
please feel free to correct the above!

Hope this helps!

Are solid stainless steel rods any less vulnerable?
What alloy is used for major standing rigging; there must be some less prone
to chloride/stress attack, or?
I worked with some higher than 316 plus extra titanium alloy(32?) for
seawater boiler; it was a much better choice than regular 316.
I am not sure if this alloy is being offered in steel rope shape.
Any one knows more about it?
thanks

noexpert wrote:
Are solid stainless steel rods any less vulnerable?
What alloy is used for major standing rigging; there must be some less prone
to chloride/stress attack, or?
I worked with some higher than 316 plus extra titanium alloy(32?) for
seawater boiler; it was a much better choice than regular 316.
I am not sure if this alloy is being offered in steel rope shape.
Any one knows more about it?
thanks

Most sailboat rigging is 304. Some is 316 but it's a bit weaker than
304 (about 10%).

Rod rigging is usually Nitronic 50. More corrosion resistance but no
warning of failure like broken strands. About twice the cost of wire
rope so it's restricted to racing boats

Evan Gatehouse

noexpert wrote:

Are solid stainless steel rods any less vulnerable?
What alloy is used for major standing rigging; there must be some less prone
to chloride/stress attack, or?
I worked with some higher than 316 plus extra titanium alloy(32?) for
seawater boiler; it was a much better choice than regular 316.
I am not sure if this alloy is being offered in steel rope shape.
Any one knows more about it?
thanks




Just a suspicion, but it seems to me that the problem here is a result of
the swaging process itself.

When the swage is squeezed, there should be uneven compression which would
cause the material to yield unevenly - leading to rather high localized stress
concentrations. In-service vibration, over time, should lead to exactly the
kind of cracks described by GBM.

FWIW, for highly stressed aircraft cables, the terminals (ends) are *Rolled*
rather than squoze...

Richard

"cavelamb" wrote

Just a suspicion, but it seems to me that the problem here is a result of
the swaging process itself.

When the swage is squeezed, there should be uneven compression which would
cause the material to yield unevenly - leading to rather high localized
stress
concentrations. In-service vibration, over time, should lead to exactly
the
kind of cracks described by GBM.

FWIW, for highly stressed aircraft cables, the terminals (ends) are
*Rolled*
rather than squoze...

Richard

Could be, but experience shows that this type of failure does not occur in
fresh water. The experts advise that it is the presence of chlorides in
crevices with an oxygen deficient atmosphere and stress that cause the
failure. The whole swage and the wire strands are stressed to various
degrees.

GBM