Was I lucky or what? Forestay failure!
- Thread starter Tally Ho
- Start date
When you get what the original design looked like either send me a copy or post it here. It sure is looking to me like either a bad design or a bad implementation of that design. Still waiting on the parts.
dj
I am noticing how close the anchor ways are to the chain plate. Might there be some repeated collision of anchor chain, shackle, or anchor shank while raising and lowering that, over time, stresses the chainplate?
-Will
-Will
Great that you were able to locate the original rig shop for your 322. They should be a terrific resource for you going forward with re-rigging.
That slot in the broken attachment appears to be the weak link & go figure; that’s where the fracture occurred. Of course, it took approximately 35 years for it to break; however, if the slot could be eliminated or the plate be reinforced, that may be a better design.
We all hope that we are cool headed and resourceful enough to get home safely when shit goes sideways.
Good job!
Good job!
Pulled all of the old rigging off the mast today. Quite interesting how things are put together. The lower shrouds were pinned under the spreader, which was held in place with a pin and cotter pin in the middle. Seems almost fragile, but as long as the cotter pin stayed in, nothing could (easily) come undone.
The furler was the biggest challenge. I had no idea how it was secured to the stay. It is an old CDI furler. But once I got the drum separated and off, it revealed the turn buckle. Spin off the lower stud and the bottom of the furler (bearings) came off. Then the torsion tube slide off, revealing the top stud of the turnbuckle. Spin that off and the foil sections slid off.
I will be putting the parts for this furler on the Parts page if anyone has an old CDI furler nd needs parts.
I was going to put the bow chainplate back on today, but an email from dLj that suggested that I should see if the fabricator could bend it with a radius instead of the sharp tool mark bends.
So I called the fabricator, explained the concern and he said he could use a different “top” on the press that would be a little more radiused. So I asked him to make a new one… we will see what it looks like. I appreciate Dave’s looking at the part and suggesting a better way to make it.
Always something on a boat!
Greg
The furler was the biggest challenge. I had no idea how it was secured to the stay. It is an old CDI furler. But once I got the drum separated and off, it revealed the turn buckle. Spin off the lower stud and the bottom of the furler (bearings) came off. Then the torsion tube slide off, revealing the top stud of the turnbuckle. Spin that off and the foil sections slid off.
I will be putting the parts for this furler on the Parts page if anyone has an old CDI furler nd needs parts.
I was going to put the bow chainplate back on today, but an email from dLj that suggested that I should see if the fabricator could bend it with a radius instead of the sharp tool mark bends.
So I called the fabricator, explained the concern and he said he could use a different “top” on the press that would be a little more radiused. So I asked him to make a new one… we will see what it looks like. I appreciate Dave’s looking at the part and suggesting a better way to make it.
Always something on a boat!
Greg
Greg and I have been communicating in the background. He is pretty sure that the chainplate that broke was not original to the boat. There were modifications done by a previous owner or boat yard where the anchor roller and this chainplate were likely modified.
He sent me the part that broke and a section of the part that didn't break. Here's a picture of what he sent me.
Looking at the fracture, I was initially surprised at the appearance of the fracture origin. There are literally dozens of fracture initiation locations spread across a whole region of the tension side of the piece.
Here's a closer image of the port side section.
All of these fracture origins were pre-existing. As I was looking at the fracture surface, I realized that all of these origins were created during bending. So I took some photos of the bend lower down that did not break to give an idea of what happened.
Here's a closer view at the root of that bend - sorry - it's really hard to get good images there...
The bottom line - that chain plate was installed with pre-existing cracks right at the high stress tension side of this chainplate. It was only a matter of time before it broke.
If anyone has any questions - let me know.
dj
He sent me the part that broke and a section of the part that didn't break. Here's a picture of what he sent me.
Looking at the fracture, I was initially surprised at the appearance of the fracture origin. There are literally dozens of fracture initiation locations spread across a whole region of the tension side of the piece.
Here's a closer image of the port side section.
All of these fracture origins were pre-existing. As I was looking at the fracture surface, I realized that all of these origins were created during bending. So I took some photos of the bend lower down that did not break to give an idea of what happened.
Here's a closer view at the root of that bend - sorry - it's really hard to get good images there...
The bottom line - that chain plate was installed with pre-existing cracks right at the high stress tension side of this chainplate. It was only a matter of time before it broke.
If anyone has any questions - let me know.
dj
And based on Dave’s analysis and on his recommendation, I asked the fabricator if he could try making the chainplate with a slight radius at the bends instead of the hard, tool-marked bends.
The first one he made looked EXACTLY like the one that failed…but that was my fault because I asked him to make just like the original. But after looking at the similarities of the bends on both the old one nd the new one, I called him and discussed the technique used to bend it and our concerns with the tool marks at the bends. He is making the new one this week, and we will see how it comes out.
Big thanks to Dave for taking an interest in my project.
Greg
The first one he made looked EXACTLY like the one that failed…but that was my fault because I asked him to make just like the original. But after looking at the similarities of the bends on both the old one nd the new one, I called him and discussed the technique used to bend it and our concerns with the tool marks at the bends. He is making the new one this week, and we will see how it comes out.
Big thanks to Dave for taking an interest in my project.
Greg
Best of luck with that new plate.
You are most welcome - I'd hate to see you with the same issue after all the work you'll be doing and the near miss you just had....
dj
I picked up the new forestay chainplate this afternoon...
All of the bends look a lot better, no sharp bends or cuts or tool marks.
Rigger is meeting me at the marina tomorrow to discuss the rigging work and I will test this new chainplate to make sure it fits.
All of the bends look a lot better, no sharp bends or cuts or tool marks.
Rigger is meeting me at the marina tomorrow to discuss the rigging work and I will test this new chainplate to make sure it fits.
I sure hope that new one fits well. The first piece is a disaster waiting to happen...
They probably use a hydraulic press with a die head that pushes down into a vee shaped die. And yes - it's using a larger radius center die.
dj
They probably use a hydraulic press with a die head that pushes down into a vee shaped die. And yes - it's using a larger radius center die.
dj
Yes, the first one was bent over a sharper tool (I don’t know the jargon either). After talking to the machine shop about the concern over the tool marks he said he could use a larger rounded “top”.
There is definitely a difference in the bends.
Greg