Dye Penetrant vs X-ray Testing of Chainplates???

[MJH]

Originally Posted by Sharkbait Steve

I intend to replace the standing rigging on my 1976 Ingrid 38. The chainplates are original. Seems like it would be a good idea to either inspect the chainplates or just replace them. Looking for input on dye penetrant vs. x-ray. DIY dye penetrant would be the least expensive way to go. I've found some dye penetrant test kits online: Magnaflux for about $270 and Dynaflux for about 1/3 that much. Anyone have experience with either of these? Would testing the chainplates while they are still bolted to the hull yield meaningful results? I haven't gotten a price yet for having the chainplates professionally inspected but I suspect that it will not be cost effective vs just replacing them. Any input/comments will be greatly appreciated!!!

DLJ raises an interesting point, out of the millions of sailboats out there how many suffer chainplate breakage every year? I have wondered the same thing. You would think that with such catastrophic results someone would be tracking it...but I couldn't tell you the last time I heard of such a failure. Perhaps, the local rigging shops would have some idea. A number of sailboats are dismasted every year (mostly racers?) but the breakage happens higher up the mast and causes are other components or operator error not the chainplates. Another thought, insurance companies don't require chainplate inspections or periodical replacement to my knowledge.

I'm not saying chainplate care isn't important, but hearing the details from those that suffered from a chainplate failure would be educational for all of us. It seems to me that if you are going to undertake a particularly challenging sailing adventure you best give it some thought.

[boatpoker]

Originally Posted by MJH

A number of sailboats are dismasted every year (mostly racers?) but the breakage happens higher up the mast and causes are other components or operator error not the chainplates.
.

You've been tracking that ?

[MJH]

Originally Posted by boatpoker

You've been tracking that ?

Just read the racing section of the sailing rags.

[Nicholson58]

Originally Posted by Sharkbait Steve

I intend to replace the standing rigging on my 1976 Ingrid 38. The chainplates are original. Seems like it would be a good idea to either inspect the chainplates or just replace them. Looking for input on dye penetrant vs. x-ray. DIY dye penetrant would be the least expensive way to go. I've found some dye penetrant test kits online: Magnaflux for about $270 and Dynaflux for about 1/3 that much. Anyone have experience with either of these? Would testing the chainplates while they are still bolted to the hull yield meaningful results? I haven't gotten a price yet for having the chainplates professionally inspected but I suspect that it will not be cost effective vs just replacing them. Any input/comments will be greatly appreciated!!!

My chainplates on our 1984 Camper & Nicholson are 3x3/4x24. Two per side. I removed all four and polished the tea stains away with a very fine grit in my D-A orbital sander. Hair line cracks all around all of them were plain to the naked eye. A jeweler’s loop made them huge. I replaced all with grade 5 titanium.

[BBill]

Originally Posted by MJH

Just read the racing section of the sailing rags.

If it was my boat the 40 yr old chainplates would be replaced and probably in bronze. Ive had standing wire and mast fitting let go while sailing. You really don't want to go there.

Yrs back I stayed in Ft Laud Fl a few months and spent time at a few high end yards on the Dana cutoff canal. This was the place maxi ocean racers were doing their annual refits. Their normal routine was to replace the standing wire every yr and have the hardware magnafluxed. I don't know jack about magnafluxing but they must have a way to do 316. They also freshwater soaked all the turnbuckles and wiped down with lanolin.

[Icarus]

Originally Posted by Sharkbait Steve

I intend to replace the standing rigging on my 1976 Ingrid 38. The chainplates are original. Seems like it would be a good idea to either inspect the chainplates or just replace them. Looking for input on dye penetrant vs. x-ray. DIY dye penetrant would be the least expensive way to go. I've found some dye penetrant test kits online: Magnaflux for about $270 and Dynaflux for about 1/3 that much. Anyone have experience with either of these? Would testing the chainplates while they are still bolted to the hull yield meaningful results? I haven't gotten a price yet for having the chainplates professionally inspected but I suspect that it will not be cost effective vs just replacing them. Any input/comments will be greatly appreciated!!!

Dye testing will show hairline cracks....metal fatigue won't show up.
Non destructive testing is usually done with ultra sound....
I would replace the chain plates and fasteners for piece of mind...

[Searles]

Dlj maybe right ,but dollar for kilo of metal in the marine environment only top class bronze comes close to monel, s/s in not a life time metal in the marine environment even 2205 a d aquamet 22 have there limitations ,60 years in the trade and many many sea miles ,I’m am still learning .⚓️⛵️

[BBill]

Originally Posted by dlj

316 has an endurance limit, so as long as the design was such that the loading remained under the endurance limit, they can go on for another billion cycles. 40 years has nothing to do with it.

You specified 316 for a propellor shaft? Very bad choice of material.

Any NDE inspection of that shaft would have picked up the obvious opening to the surface seen in your image. Or your NDE inspection was sub-par.

Here's an image for you - nothing on the surface. This one you wouldn't pick up from dye penetrant. This is internal to the material - oh right - it's NOT 316 material... It's 440C that was improperly heat treated post coating. Scary photo for sure don't you think? But it has nothing to do with the issue with the chainplates. It's a different material, undergoing a different degradation mechanism. If your propellor shaft is not 316, as it shouldn't be, then don't compare apples to oranges.

Bronze and monel prop shafts never had the problem SS does. You normally replaced them when bent or scored from packing glands. Production boats started using SS in the late 60s/early 70s and it only took a couple yrs when abundant problems started showing up with surface corrosion, crevice cracks and basically trashed shafts. It all started when SS and bronze prices flip flopped. SS has never been the benchmark for best shaft material.

[Disailor]

The chainplates on my Morgan OI were attaches with carriage bolts and so had square holes punched in them. Letting "PBlaster" penetrating oil soak in and dusting with talcum powder I was able to find enough cracks emanating from the corners of these holes to replace them all.