You have them out...just replace them all...good..juts heard you say it. Should just be done every 10 years as a matter of fact. Titanium chainplates lengthens that by a lot. -Rebecca on SV Brick House
Nick while you are checking standing have a look at the upper mast anchors also. usually over looked as they at the top of the mast but just as important, you are at the dock it is the time to do it buddy.
Love your productions. Honest, creative and real. Hold your heads high, resolving these plates is paramount to peace of mind and literally foundational to sailing forward. You have both experienced several challenges and catastrophes (hurricanes for example) and have persevered through all of them through displaying a high level of humility, patience and prayer. I know you will succeed in your endeavors largely from witnessing your approach to issues and your actions thereafter. I wish you all level vibes.
You should be looking at the correct alignment of those chain plates so that they take the stress correctly. Presently they are badly aligned and that is essentially why there is a crack in one side of that chanplate.
The way I have found to seal chainplates is this: Use butyl tape on deck metal fittings that compress. Like the plates that seal your chainplates. Also for the chainplates themselves you can and should still use the butyl tape. The thing is over the top of the tape you should lay a layer of 4200, because it does a better job of filling little cracks, but it doens't last as well. With the two materials in play, you cover your bases better.
From what I could see these chain plates have suffered stress fractures. Replace complete with bolts to make sure. Bow plate could be worth a look too. John of Gosport.
Who makes that boat?? Why didn't they align the chainplates with the rigging so that all the stress moves through the plate linearly? (This is your chance to do that by changing the orientation below deck.)
I would have welded the deck plate to the chainplate and used butyl tape under the plate, also if possible the deckplate should be through bolted. How is the sandwich in the deck, there has been water ingress over a number of years which also should be attended to, if no sandwich less of a problem. Good luck in the fixing of the rigamole. Fair winds and happy sailing, although none at the moment. Europe is about to open so hopefully the same in the Caribbean!
That's scary - will check mine out as soon as they let us back into the marina here in the UK. Hope you guys are OK and looking forward to more sailing!!
You made the right call. That is intergranular corrosion. In a nut shell corrosion is on the inside of the metal and over time it will eat the metal up like a cancer till the part looses strength and fails. I am guessing that some of the plating was worn off/chipped (can see the black spots on the chain plates). This allows water to enter the inner grains of the metal part. Add some salt water and you have a ticking time bomb. Glad you were close to a safe harbor when you had your issues.
Great video ... I have been following your videos ... one question, i noticed you using a map that reads " renaissance islands" ... to find the repair shop ... can you please provide us with the publication or where to get it? .. we have lose maps but not everything in one publication .. thanks in advance
⛵ I guess if there's any good things come out of this it is good that the failure of the chain plates gave you a heads up. Much better you were nearby a safe-haven when the first one failed. Like you I have a feeling all of those are going to have to be replaced which is probably in the long run the best thing to do. I hope you get it done quickly and it doesn't break the bank. Thanks for the video.
After reading Rebecca's post from SV Brick House I didn't know you could get them made in Titanium. But they must be EXPENSIVE🤪! You're safe and at a good shop to get all new plates made. If it was easy rich people would be doing this all the time 😂🤣😆😁 Stay safe. Your friend from Syracuse New York.
NEXT TIME - and yes, there will be a next time. Wrap some masking tape around the toggle bolts of each turnbuckle to mark where the old position was. This makes it much easier to get a quick start on retensioning all the stays. Simply do everything back up as it was and then check mast alignment and tension side to side, if none of the replacement chain plates arsignificantly different you might get away with a very quick retension job.
It seems pretty clear what caused the failing of that chainplate, namely the butyl tape. It is not widely known but even stainless steel will corode in anaerobic environment. Exactly what is created by sealing the chainplates with butyl tape where they pass through the deck. It is a design fault that has to be dealt with and that can be done rather easily. As one comment below already stated the angle of the chainplates towards the shrouds is also wrong, they seem not to be in line. Once you determined their right angle make the necessary markings when dry fitting the deck plate and the chainplate i.o.t. prepare both to be welded to each other. This new chainplate thing is now sealed by applying some sealant of whatever preference underneath the rim of the deck plate but not onto the chainplate proper. What little corrosion will occur underneath the deckplate can be ignored for many years since it doesn't weaken the structural part, the original chainplate, any more.
As others have mentioned, titanium chainplates are now a reasonably priced option (not sure if so where you are). Any chainplate issues would pretty much cease to exist. I will be looking in that direction when its time.
That is crevice corrosion. Those all definitely need to be replaced. Without advanced testing, that would probably cost more than making new parts, it's impossible to know how deep some of those cracks go. But the the cracks at 10:30, 10:50, 11:15, etc., appear to be all the way through the thickness of the material -- very bad. Those are junk. I am curious if those are made of 316 stainless steel, which has some resistance to crevice corrosion, or if someone went with a different stainless that was cheaper or easier to find.
You guys were fortunate. Should not be to bad , its flat SS bar with 6 .... 1/2 in holes. Two guys could make those in a few beers and a pizza. . my cost guess-tamate is about 100 per plate with bolts no rigging tuning... Be less if you drill your own holes.
The primary cause of this failure is because the slots that chainplates pass through were not beveled on the top edge. Doing that simple step ensures that the sealant makes an O-ring type seal that is effective at keeping water out even if the chainplate gets flexed. Stainless steel experiences this type of corrosion in any place where there is no oxygen present, thats why you only see it where the chainplate was through the deck while the top and bottom look just fine.
If your glass was built up higher where the chain plates go thru ,water running along the deck would never enter the chainplate. I seal mine up with 3m 4000uv or you can use 4200
That's the common practice in the industry and what insurance companies want. Most people have no idea how old the rigging is when buying a boat because sellers don't keep good records (literally, that is 95% of the time). Some rigging does last longer than 10 years, it really depends on the quality of installation and maintenance that was done over time. When you buy a boat that is not factory new you should always assume that ZERO maintenance was done unless the previous owner can produce receipts to prove what was done and when it was done. I've worked on boats that were only 15 years old that had failing rigging and hardware because the factory never used isolating compounds on stainless hardware while I've also worked on boats over 40 years old where bolts and screws came out easily and I could still see the residue of yellow isolating compound (Duralac) on the threads.
Perfect example of why stainless steel has no place on sailboat chainplates! As others have mentioned, it's called crevice corrosion and it is characteristic of all different grades of SS when they are denied oxygen and kept wet with salt water where they penetrate the deck. . The fact that 99.99% of production sailboats use stainless steel for chainplates just proves that it is cheap, not safe or reliable. Install them improperly like yours and they'll be rotted out again in ten years. If you really want to create a bomb, chrome plate them or glass over the areas under deck. There are four proper materials for chainplates: 1- Silicon Bronze 2- Titanium 3- Integral carbon (or glass uni if you don't mind the bulk). 4- Aluminum or steel when integral to welded metal hulls.
Beddle tape is crap dosent stick errods away in no time useless . I've seen it fail when it's supposed to seal I would try a waterproof patch with a bedding material and a silicon sealer
No... If the chainplates were at an angle and that angle was wrong it could potentially cause flexing in the chainplate. These are straight chainplates and there doesn't seem to be any shroud angle at the turnbuckle connection. The correct alloy to use is 316L Stainless that is annealed, and stainless that has been tempered becomes too brittle so older boat that have 304 stainless are at risk (but only if the shroud angle is pulling on the chainplate). Satori's situation is lucky in many ways, but also having straight & flat chainplates are the easiest and least expensive to fabricate. There are many boats that have chainplates with a curve to match the hull and a bend to create the shroud angle, matching those bends on new stock is why a new set of chainplates can cost thousands. The biggest manufacturer defect here is that the slots for the chainplates should have been beveled at the top which creates a superior seal with the butyl tape. If that had been done correctly and the sealant refreshed every 5 years, water would never have gotten into the gap to cause the corrosion.
They look like low grade 304 SS. One of them looked slightly concaved...in other words pressed out of a sheet and not flat bar, then chromed. Pressed plate steel would be pre stressed and open to failure in this application. Its not cheap but 316 SS flat bar is the option if they're gonna do remakes. But they'll know that. Doubt they'd have time to rechrome anything. (Im a marine engineer with 33 years exp.)
If you are a Marine Engineer you'd know that 304 SS or 316L SS is never chromed. Not only is it a really bad idea, its not a common practice with any Sailboat manufacturer, ever. You correct that it is likely that they are 304 rather than 316, many boats of that era were. 304 is stronger than 316L but lacks the chromium content in the alloy (in it, not on it) to be as corrosion resistant. Thats also why the 304 will have crevice corrosion at a faster rate than 316L which is exactly what we saw in the video, each chainplate experiencing various stages from on-set to failure. That thickness of bar is not pressed, that's just not the way it is manufactured... lots of small dinghies and racers with very light hardware are pressed but those chainplates looked to be at least .250 with .625 clevis pin (just by eye). 316L is more expensive, but it isn't crazy if you know where to order it from. I just checked on of my online suppliers, $378 for 316L flat bar (.25 thick x 1.75 wide x 36 long) qty 10 so a total of 36 feet. That is before the current 20% discount being offered and less shipping of course, and that qty is probably too much for the 8 or so chainplates they would need. I could make these in a day, then polish and neutralize them the next morning for about $200 in labor.
You are cruising.....why are you rushing to get things done and get out of there. Take your time do it right. Rushing yourself and the workers leads to a sloppy rushed work product. Take your time and be thorough, especially with something as important as your rigging.
Magnetic SS ? Never heard of that in my 30 years as a marine engineer. Looks more like low grade 304 SS. That said they could just be chromium plated steel. The owner was pissed about letting his boat go on the cheap ? 🤔🤔🤔 Im guessing there was more to this sale than met the eye.
@@eyemstillhear If you had any kind of engineering degree (much less a Marine Engineering degree) you would know that Ferritic and Martensitic stainess steels (the 400 series) are magnetic (and often called that) as are some duplex stainless steels such as 2205. Duplex stainless has been in common use offshore for about 20 years now... Some newer boats are using duplex or superduplex as standard in rigging components due to reduced tendency to suffer chloride stress corrosion cracking. All engineers, regardless of flavor, are exposed to a basic materials course as part of their degree program. You would have learned about "magnetic" stainless steel if you had an engineering degree.
what you appear to have is chloride stress corrosion cracking, it is a common problem with stainless steel. It is caused by the chloride in the stainless steel.
It's caused by chloride in the environment, namely the salts in seawater and salt air. Chloride isn't one of the ingredients in stainless steel. The lack of oxygen within the hull (sealed with goo) also prevents the passivization layer in stainless steel to reform as the exterior suffers micro cracks from chloride induced stress corrosion cracking. Those micro cracks then work their way through the stainless steel thus the "wonkiness" in other areas of the chainplate.
You have them out...just replace them all...good..juts heard you say it. Should just be done every 10 years as a matter of fact. Titanium chainplates lengthens that by a lot. -Rebecca on SV Brick House
Nick while you are checking standing have a look at the upper mast anchors also. usually over looked as they at the top of the mast but just as important, you are at the dock it is the time to do it buddy.
Love your productions. Honest, creative and real. Hold your heads high, resolving these plates is paramount to peace of mind and literally foundational to sailing forward. You have both experienced several challenges and catastrophes (hurricanes for example) and have persevered through all of them through displaying a high level of humility, patience and prayer. I know you will succeed in your endeavors largely from witnessing your approach to issues and your actions thereafter. I wish you all level vibes.
Great and instructional video. Many years in this and never seen so clear, congrats...!!!
I learned from this. I had no idea they were that long and deep inside the boat! Thank you.
Definitely consider replacing with titanium chainplates...and titanium tangs too. Allied Titanium could certainly help you. -Rebecca on SV Brick House
You should be looking at the correct alignment of those chain plates so that they take the stress correctly. Presently they are badly aligned and that is essentially why there is a crack in one side of that chanplate.
The way I have found to seal chainplates is this: Use butyl tape on deck metal fittings that compress. Like the plates that seal your chainplates. Also for the chainplates themselves you can and should still use the butyl tape. The thing is over the top of the tape you should lay a layer of 4200, because it does a better job of filling little cracks, but it doens't last as well. With the two materials in play, you cover your bases better.
Glad you guys are safe and this happened close to shore and services. Better than the middle of the pacific.
You are doing the right thing and thank goodness you did not loose your rig.
From what I could see these chain plates have suffered stress fractures. Replace complete with bolts to make sure. Bow plate could be worth a look too. John of Gosport.
Great video guys!, Hate for the issues but it kinda goes with the territory! Most yachts don't get used as much as SATORI!
Who makes that boat??
Why didn't they align the chainplates with the rigging so that all the stress moves through the plate linearly?
(This is your chance to do that by changing the orientation below deck.)
Thanks for the close look at the chain plates, what we can’t see truly can kill us. Thank goodness you weren’t mid ocean
I would have welded the deck plate to the chainplate and used butyl tape under the plate, also if possible the deckplate should be through bolted. How is the sandwich in the deck, there has been water ingress over a number of years which also should be attended to, if no sandwich less of a problem.
Good luck in the fixing of the rigamole.
Fair winds and happy sailing, although none at the moment. Europe is about to open so hopefully the same in the Caribbean!
That's scary - will check mine out as soon as they let us back into the marina here in the UK. Hope you guys are OK and looking forward to more sailing!!
The condition of those chainplates is sobering. You were really lucky not to have had a major rig failure. This project looks expensive.
You made the right call. That is intergranular corrosion. In a nut shell corrosion is on the inside of the metal and over time it will eat the metal up like a cancer till the part looses strength and fails. I am guessing that some of the plating was worn off/chipped (can see the black spots on the chain plates). This allows water to enter the inner grains of the metal part. Add some salt water and you have a ticking time bomb. Glad you were close to a safe harbor when you had your issues.
Great video ... I have been following your videos ... one question, i noticed you using a map that reads " renaissance islands" ... to find the repair shop ... can you please provide us with the publication or where to get it? .. we have lose maps but not everything in one publication .. thanks in advance
It's much to your credit to take the effort to remove and inspect the chainplates! You can be proud!
I thought the bridge guy was just having a joke with you ...... lol
I feel for you. I know what it's like to have a project and a limited budget. I hope it all works out.
⛵ I guess if there's any good things come out of this it is good that the failure of the chain plates gave you a heads up. Much better you were nearby a safe-haven when the first one failed. Like you I have a feeling all of those are going to have to be replaced which is probably in the long run the best thing to do. I hope you get it done quickly and it doesn't break the bank. Thanks for the video.
Excellent video and a cliff hanger as well :) When you have these made do you need to ask for 316 stainless or is that the standard?
WOW!!! - Scariest boat video of all times! Hidden cracks in perfectly good looking chainplates. A boat owner´s ultimate nightmare...
After reading Rebecca's post from SV Brick House I didn't know you could get them made in Titanium. But they must be EXPENSIVE🤪!
You're safe and at a good shop to get all new plates made.
If it was easy rich people would be doing this all the time 😂🤣😆😁
Stay safe. Your friend from Syracuse New York.
NEXT TIME - and yes, there will be a next time. Wrap some masking tape around the toggle bolts of each turnbuckle to mark where the old position was. This makes it much easier to get a quick start on retensioning all the stays. Simply do everything back up as it was and then check mast alignment and tension side to side, if none of the replacement chain plates arsignificantly different you might get away with a very quick retension job.
Clearly an Aussie!! He said "Motor Yacht" not "Mighty Yacht". lol. Greetings from Australia btw.
Those chainplates are looking real good!
One question, Where did you guys get the iPad mount?
The team at FKG do great work 👍⛵️
Good reminder to me that need to pull and inspect the chain plates on my new to me but 40 year old I36.
Thanks for another great video guyd..you made my day !...."The Mighty Satori"..sounds great :)))
ohhh buddy! can't wait to get mine out
Suppose that is a good way to make use of the time... good luck with all the repairs and stay save!
The guy said “motor yacht “ not “mighty” , quite a few MY Satori listed on Marine traffic .com
It seems pretty clear what caused the failing of that chainplate, namely the butyl tape. It is not widely known but even stainless steel will corode in anaerobic environment. Exactly what is created by sealing the chainplates with butyl tape where they pass through the deck. It is a design fault that has to be dealt with and that can be done rather easily. As one comment below already stated the angle of the chainplates towards the shrouds is also wrong, they seem not to be in line. Once you determined their right angle make the necessary markings when dry fitting the deck plate and the chainplate i.o.t. prepare both to be welded to each other. This new chainplate thing is now sealed by applying some sealant of whatever preference underneath the rim of the deck plate but not onto the chainplate proper. What little corrosion will occur underneath the deckplate can be ignored for many years since it doesn't weaken the structural part, the original chainplate, any more.
As others have mentioned, titanium chainplates are now a reasonably priced option (not sure if so where you are). Any chainplate issues would pretty much cease to exist. I will be looking in that direction when its time.
Tough stuff to cut stainless hope you filmed the manufacture
Unfortunately, no. Many of the workers were not keen on being filmed.
I would be redesigning those plates to be stronger or thicker or wider material or some combination involving more than one of these options.
If Saba opens the port next week. Come to long haul restaurant and bar. We are done with the lockdown. Stay safe on st Martin.
That is crevice corrosion. Those all definitely need to be replaced. Without advanced testing, that would probably cost more than making new parts, it's impossible to know how deep some of those cracks go. But the the cracks at 10:30, 10:50, 11:15, etc., appear to be all the way through the thickness of the material -- very bad. Those are junk. I am curious if those are made of 316 stainless steel, which has some resistance to crevice corrosion, or if someone went with a different stainless that was cheaper or easier to find.
What kind of dog is that? Cool little dude!
Love the vids!
Cool stuff. Thanks
The name of your vessel sounds oddly familiar. Where did you purchase it, if you don’t mind me asking? I might have sailed on it as a teenager.
You guys were fortunate.
Should not be to bad , its flat SS bar with 6 .... 1/2 in holes. Two guys could make those in a few beers and a pizza. . my cost guess-tamate is about 100 per plate with bolts no rigging tuning... Be less if you drill your own holes.
Hopefully his royal highness will find an attractive and willing "friend" while on shore leave.
She doesn't have to be willing in dog land yet, lol.
The wonky parts are welds where they were previously repaired
3:15 Motor Yacht Venus, built for the late Steve Jobs.
Aren’t you all on the hard in Lankawi now?
Why no videos in the Arthur link?
Are the new plates 316L or titanium?
wholly cow!!! Is this all from age, saltwater or both?
The primary cause of this failure is because the slots that chainplates pass through were not beveled on the top edge. Doing that simple step ensures that the sealant makes an O-ring type seal that is effective at keeping water out even if the chainplate gets flexed. Stainless steel experiences this type of corrosion in any place where there is no oxygen present, thats why you only see it where the chainplate was through the deck while the top and bottom look just fine.
If your glass was built up higher where the chain plates go thru ,water running along the deck would never enter the chainplate. I seal mine up with 3m 4000uv or you can use 4200
Weiner? We call it the lipstick.
I wish I could watch one sailing channel that didn't show how to fix the chain plates,change the fuel filter clean the carb on outboard ect.
The plates look they were welded in the past
I thought the rigging was good for 10 yrs. due to insurance? Glad you'll area ok.
That's the common practice in the industry and what insurance companies want. Most people have no idea how old the rigging is when buying a boat because sellers don't keep good records (literally, that is 95% of the time). Some rigging does last longer than 10 years, it really depends on the quality of installation and maintenance that was done over time. When you buy a boat that is not factory new you should always assume that ZERO maintenance was done unless the previous owner can produce receipts to prove what was done and when it was done. I've worked on boats that were only 15 years old that had failing rigging and hardware because the factory never used isolating compounds on stainless hardware while I've also worked on boats over 40 years old where bolts and screws came out easily and I could still see the residue of yellow isolating compound (Duralac) on the threads.
It seems to me that the chainplate should follow the angle of the shroud.
Perfect example of why stainless steel has no place on sailboat chainplates! As others have mentioned, it's called crevice corrosion and it is characteristic of all different grades of SS when they are denied oxygen and kept wet with salt water where they penetrate the deck. . The fact that 99.99% of production sailboats use stainless steel for chainplates just proves that it is cheap, not safe or reliable. Install them improperly like yours and they'll be rotted out again in ten years. If you really want to create a bomb, chrome plate them or glass over the areas under deck.
There are four proper materials for chainplates:
1- Silicon Bronze
2- Titanium
3- Integral carbon (or glass uni if you don't mind the bulk).
4- Aluminum or steel when integral to welded metal hulls.
Chlorides are notorious for pitting stainless.
Beddle tape is crap dosent stick errods away in no time useless . I've seen it fail when it's supposed to seal I would try a waterproof patch with a bedding material and a silicon sealer
Aren’t those cracks due to the angle of pressure? Looks like a bit of a design fault!
No... If the chainplates were at an angle and that angle was wrong it could potentially cause flexing in the chainplate. These are straight chainplates and there doesn't seem to be any shroud angle at the turnbuckle connection. The correct alloy to use is 316L Stainless that is annealed, and stainless that has been tempered becomes too brittle so older boat that have 304 stainless are at risk (but only if the shroud angle is pulling on the chainplate). Satori's situation is lucky in many ways, but also having straight & flat chainplates are the easiest and least expensive to fabricate. There are many boats that have chainplates with a curve to match the hull and a bend to create the shroud angle, matching those bends on new stock is why a new set of chainplates can cost thousands. The biggest manufacturer defect here is that the slots for the chainplates should have been beveled at the top which creates a superior seal with the butyl tape. If that had been done correctly and the sealant refreshed every 5 years, water would never have gotten into the gap to cause the corrosion.
Cool😎
You know what B.O.A.T. stands for,,,,,,bust out another thousand,, never a truer phrase spoken!!!!!
Arthur is pissed about the chain plates he thinking about demoting you to shit shoveler
Don't think this was butyl tape related. More likely this was developed before you resealed the plates...
Shudder to think of what may be going on in the deck core around the chainplates
They look like low grade 304 SS. One of them looked slightly concaved...in other words pressed out of a sheet and not flat bar, then chromed. Pressed plate steel would be pre stressed and open to failure in this application. Its not cheap but 316 SS flat bar is the option if they're gonna do remakes. But they'll know that. Doubt they'd have time to rechrome anything. (Im a marine engineer with 33 years exp.)
If you are a Marine Engineer you'd know that 304 SS or 316L SS is never chromed. Not only is it a really bad idea, its not a common practice with any Sailboat manufacturer, ever. You correct that it is likely that they are 304 rather than 316, many boats of that era were. 304 is stronger than 316L but lacks the chromium content in the alloy (in it, not on it) to be as corrosion resistant. Thats also why the 304 will have crevice corrosion at a faster rate than 316L which is exactly what we saw in the video, each chainplate experiencing various stages from on-set to failure. That thickness of bar is not pressed, that's just not the way it is manufactured... lots of small dinghies and racers with very light hardware are pressed but those chainplates looked to be at least .250 with .625 clevis pin (just by eye). 316L is more expensive, but it isn't crazy if you know where to order it from. I just checked on of my online suppliers, $378 for 316L flat bar (.25 thick x 1.75 wide x 36 long) qty 10 so a total of 36 feet. That is before the current 20% discount being offered and less shipping of course, and that qty is probably too much for the 8 or so chainplates they would need. I could make these in a day, then polish and neutralize them the next morning for about $200 in labor.
The biggest reason these failed is not because of the alloy, its because the deck slots weren't beveled when the sealant was applied.
It would be nice to have those plates made from titanium, no corrosion. Just saying.
Hi Nick...one of your readers suggests it may be "Hydrogen embrittlement" . Please look it up...FYI
If those are original I would be bothering the boat manufacturer. It looks like defects in the metal
You are cruising.....why are you rushing to get things done and get out of there. Take your time do it right. Rushing yourself and the workers leads to a sloppy rushed work product. Take your time and be thorough, especially with something as important as your rigging.
Trying to rush a job that important just to go cruise to some islands makes no sense, slow down.
Not that I have any expertise, but it seems marine stainless steel be a better fit for these. Or possibly another anodized type of coating.
Just wondering, is that magnetic stainless steel?
Magnetic SS ? Never heard of that in my 30 years as a marine engineer. Looks more like low grade 304 SS. That said they could just be chromium plated steel. The owner was pissed about letting his boat go on the cheap ? 🤔🤔🤔 Im guessing there was more to this sale than met the eye.
@@eyemstillhear If you had any kind of engineering degree (much less a Marine Engineering degree) you would know that Ferritic and Martensitic stainess steels (the 400 series) are magnetic (and often called that) as are some duplex stainless steels such as 2205. Duplex stainless has been in common use offshore for about 20 years now... Some newer boats are using duplex or superduplex as standard in rigging components due to reduced tendency to suffer chloride stress corrosion cracking. All engineers, regardless of flavor, are exposed to a basic materials course as part of their degree program. You would have learned about "magnetic" stainless steel if you had an engineering degree.
what you appear to have is chloride stress corrosion cracking, it is a common problem with stainless steel. It is caused by the chloride in the stainless steel.
It's caused by chloride in the environment, namely the salts in seawater and salt air. Chloride isn't one of the ingredients in stainless steel. The lack of oxygen within the hull (sealed with goo) also prevents the passivization layer in stainless steel to reform as the exterior suffers micro cracks from chloride induced stress corrosion cracking. Those micro cracks then work their way through the stainless steel thus the "wonkiness" in other areas of the chainplate.
Have you looked at your flag lately? Proper flag or not at all! Just saying.
Hydrogen embrittlement. Parts were not baked off properly.
Hi 'bear' I've just looked that up and I'm quite sure you are exactly correct.I hope Nick reads about this...