Help analyze personal inspection findings (3 of 5) - chainplate alignment

[pillars]

Topic 3 - chainplate alignment/corrosion at touchpoint

Don Casey's Inspecting the Aging Sailboat specifically mentions to look for this standing rig issue. Unfortunately I don't have the book with me or I would include the picture from the book, however, in the attached picture you can see at least 3 different examples of cat shroud attachments that seem to exhibit corrosion at the point where the toggle comes in contact with the chainplate and one without for comparison.
My sample size of boats that I looked at was rather small, so I either I was very unlucky or this is a common problem, or maybe not a problem at all?

[Nicholson58]

The toggles look a bit questionable. To inspect, remove them and polish off all of the tea stains. Examine close in with a lens. Cracks may be very fine. If you are concerned, replace.

[CSYChip]

Surface rust on stainless steel such as your photos show is rarely an issue. A quick buff with scotchbrite will usually remove this. The thing to look for is intergranular corrosion. This will look like a fine spider web of rust lines in the metal. You may need a magnifying glass to see the rust lines. They may also take on a black rather than rust color. Buffing the metal will not remove intergranular corrosion unless it is in the very early stages. In severe cases, hitting the metal with a hammer will cause it to crack or crumble.

[Thumbs Up]

First of all, the four examples appear to be of the same toggles but at different angles. That amount of corrosion isn't always something to be alarmed about but in this case you can see that the steeper angle of the lower shroud is severely point loading one side of the pin and that the toggle strap is either deformed or assembled with the wrong strap/pin because you can see that the upper pin in these photos appears smaller then the radius of the strap and is point loading the strap. Unless you were to use a split chainplate you would always have some misalignment with this setup. The last photo (which is the same chainplate but from the other side), shows that the upper shroud is misaligned to the chainplate as well so now it is obvious that there should have been a slight bend in the chainplate itself. To correct it that chainplate will have to be removed and bent slightly inboard near the top. And if you were going to make an offer on this boat you should bring it up as an issue.

[pillars]

Thanks for the responses guys.

To be clear, these are 4 different boats, same make, similar years and models, which is why the setup looks the same.

[Thumbs Up]

To be very clear I have attached some close up views. Same boat, same chainplate.

[pillars]

To be even more clear, you are correct that the 2 on the right in your message are of the same boat as I attached the wrong picture (below is the one that was meant to be there). The two on the left in your message are of different boats and I attached the opposite view of one of them below.

Regardless, thank you for the keen eye.

[Thumbs Up]

These two images are most definitely the same chainplate and the same boat.
You can even see the marks on the threads from where the turnbuckle used to be before the "repair". I am a little bored right now so I did some digging and the photo below is the same boat. Do you see that used toggle assembly in the bottom center of the photo? Guess where that ended up? He either had to straighten and re-bend that toggle strap (likely) or press out and reinstall that pin (unlikely). Anyway, it is just like I said, the pin diameter is mismatched to the toggle strap. And this guy is a "professional" rigger. You gotta pay attention to the details!

[Thumbs Up]

I am still bored so trying to piece together how it ended up like that. That used toggle strap was part of the piece that was cut off. The original had an extra toggle assembly above the turnbuckle. I think that since the new Stalok fitting, which has right hand threads would not thread in, they flipped the turnbuckle over and had to use the old toggle fitting (with the left hand threads) below but since the hole for the chainplate clevis pin was a different size that they then installed the original lower strap (by unbending and rebending) but ended up with a mismatched assembly. The reason that they replaced those terminals in the first place was because there were not any threads left to tighten that shroud which brings up the question of why not? Bad attachment points at the mast? The bend was tuned out of the mast? Rigged wrong to begin with? I am not sure but these rigging puzzles are interesting and they do tell a story.

[roverhi]

Much of the rust on chain plates and turnbuckles is staining from surface corrosion on the wire running down onto them. It's primarily a cosmetic issue. Get some Barkeeper's Friend or other Oxalic containing cleaner, polish it up, and you're done.

Those ss strap toggles are an area to be very aware of, however. They can crack at the bend around the pin from corrosion and the turnbuckle crank around the pin. On ss, look for cracks and pitting. Any sign of this and the offending part should be replaced. The crack/pitting is a sign of internal crevice corrosion and probably extend microscopically way further than the surface spots.

The toggles are built into the turnbuckles. If the smaller diameter of the pin is an issue it's the manufacturer as they were made this way. Suppose you could use a press to push out the pin from the turnbuckle and remove/change the strap toggle but doubt anyone would do that. Really like the old Merriman bronze turnbuckles with separate bronze toggles. No corrosion issues and they last practically forever.

The chainplates are not bent to line up with the angle of the rigging. Causes a point loading on the toggle pins which isn't ideal but seems to be fairly common production boat construction practices. See that they put a washer spacer in at least one of them to keep the toggle somewhat centered on the chainplate. If the chain plates weren't so beefy could bend them into alignment with a crescent wrench. You could try it with these chainplates but doesn't look like it would work because of their thickness and the questionable strength of the hull that you'd be using as a fulcrum. The few degrees that you'd need to bend them wouldn't be an issue with work hardening the SS.

[Thumbs Up]

This was not made this way, you can see the mismatch. They had to have straightened and rebent that strap to get in on. Or removed and replaced that pin with a hydraulic press. In any case, it is incorrect.

[pillars]

Here is the starboard side, it has the same setup. Also note the shorter shroud has been replaced with a Stalok fitting.

How much of an issue is this? ThumbsUp did you happen to be there when they re-rigged this boat? Where did you take that pic?

Do these bent toggle straps need to be replaced? Is there potentially a root cause further up the rigging?

[thinwater]

Not pretty, but the only failures I have seen were at the bend in the toggle. The rubbing lower is not likely to represent a real-world failure point.


Or does someone have pictures?

[Thumbs Up]

Pillars, I was just bored and curious and found their blog. My cat has the same setup (which I just replaced this year). At the very least, those toggle jaws should be replaced. I think that this is the right part:https://www.p2marine.com/58etjlh
The chainplates should have a slight bend in them at least enough so that the upper shrouds are in alignment. I don't know if it came from the factory that way, or if they are not original but it doesn't look right. In they blog they said that they needed more adjustment because the turnbuckles were bottomed out. From the new pictures you can see that the upper shroud's turnbuckles are near the end of their adjustment as well. Someone might have wanted more rake to the mast and adjusted it that way, there could be a problem with the forestay, or it could be a problem with the beam structure built into the boat, or it could have had a poorly measured rigging replacement so you would need to determine which. By the way my cat is for sale. Take a look:https://www.sailboatlistings.com/view/56689