Chain Plate Failure !!

[Maine Sail]

Chain Plate Failure

Hi All,

This photo was sent to me by a friend yesterday. The story is they were tuning the rig when it failed. Tt seems pretty tough to pre-inspect, to prevent a failure like that one, with out a full removal on a design like this..?

Does anyone know a source for replacements or the OEM supplier to Ericson of these chain plates?

Any help on a source would be appreciated..

 

[Cory B]

Thats not pretty. I believe Navtec made them. Hopefully they still do.

 

[CaptDan]

Hi All,

This photo was sent to me by a friend yesterday. The story is they were tuning the rig when it failed. Tt seems pretty tough to pre-inspect, to prevent a failure like that one, with out a full removal on a design like this..?

Does anyone know a source for replacements or the OEM supplier to Ericson of these chain plates?

Any help on a source would be appreciated..

I'm curious - what shrouds were attached to these items? And what model boat? They don't look like chainplates, but rather through bolted pad eyes.

If an exact duplicate is required, seems a machinist could put threads on stock stainless U-bolts, or fabricate new ones from scratch.

Capt Dan G>E35II "Kunu"

 

[jmcpeak]

At least it broke while tuning and not sailing...

Looks exactly like the style I have on my 36RH.

Pins are stamped - "Navtec" but, I can't find the single eye toggles to fit them anywhere. Navtec, Shaffer, Ronstan, Hayn, etc...

If you do find the toggles let me know.

 

[Cory B]

I'm curious - what shrouds were attached to these items? And what model boat? They don't look like chainplates, but rather through bolted pad eyes.

I don't know from what type of boat Maine Sail's pictures are from, but most 80's vintage Ericsons use the same type of attachment for the shrouds, instead of traditional chainplates. Underneath the eye there is a tie-rod leading to the TAFG.

 

[Loren Beach]

Oh My...

I'm curious - what shrouds were attached to these items? And what model boat? They don't look like chainplates, but rather through bolted pad eyes.
If an exact duplicate is required, seems a machinist could put threads on stock stainless U-bolts, or fabricate new ones from scratch.
Capt Dan G>E35II "Kunu"

It might be "challenging" to get some new hi-strength U-bolts made up on a one-off basis locally, IMHO. These are most likely forgings. From the picture of the failure point, there may have been an internal flaw, judging by what appears to be corrosion at the separation point.

Sidebar: I used to work in a plant, long long ago, that refined and produced zirconium castings and machining, although no drop forging was involved. They would X-ray and ultrasound the finished parts for internal flaws. Reading the printouts and finding small anomalies was quite challenging for the lab guys, as I remember.
:nerd:
Other than Navtec, I wonder how many other marine rigging companies anywhere have much experience with this sort of metal technology -- Wichard comes to mind.

Grim photo!


Loren

 

[Matey]

The weakest link

Crevice corrosion lives .. I ran into the same issue.
http://www.ericsonyachts.org/infoexchange/showthread.php?t=7028&highlight=crevice+corrosion

I've been on kind of a quest with this stainless thing. Lots of information & mis-information I find.

W.M's stainless .. is 304 (also know as 18-8) and is made up of 18% chromium and 8% nickel. It's good, but not the best for our environment. Their 1/2-13 x 2" bolts go for $2.70 ea.

316 stainless is 16% chromium, 10% nickel and 2% molybdenum. The moly is added to help resist corrosion from chlorides.

The yard I frequent, special orders their 316 hardware from Fasco in Alameda. So I called Fasco to find what makes their stainless special.. I had an interesting chat with the salesman who confirmed my suspicion on the source of all these 304 & 316 stainless bolts. They get some from the US, some from China and some from Taiwan. In fact some from McMaster-Carr, where I had been planning on buying mine. It appears 316 stainless that meets ASME standards, is what it is.
McMaster-Carr's bolts are 316 stainless, rated at 70,000 psi tensile and a thread fit of 2A on a 1-2C scale. They are $2.40 ea. I'm leaning that way and will replace my 26 this coming month. The plates I'll inspect and replace if they show evidence of problems

Regards, Greg

 

[Chris A.]

The photo MaineSail posted is from my friend's 1987 E34 and it was for the port side cap shroud. He did not find a supplier of the part, and is getting a new one fabricated at a local fabrication shop. The old timer making the part said he would "cold bend" the stainless. They are not really U-bolts of course, as they have a flat section and 2 bends, instead of a single radius, but I guess that description is still a pretty good one. I agree a stroke of good luck to have failed at the dock with no sailing loads...

 

[treilley]

The yard I frequent, special orders their 316 hardware from Fasco in Alameda. So I called Fasco to find what makes their stainless special.. I had an interesting chat with the salesman who confirmed my suspicion on the source of all these 304 & 316 stainless bolts. They get some from the US, some from China and some from Taiwan. In fact some from McMaster-Carr, where I had been planning on buying mine. It appears 316 stainless that meets ASME standards, is what it is.
McMaster-Carr's bolts are 316 stainless, rated at 70,000 psi tensile and a thread fit of 2A on a 1-2C scale. They are $2.40 ea. I'm leaning that way and will replace my 26 this coming month. The plates I'll inspect and replace if they show evidence of problems

Regards, Greg

I buy all my high load SS from Mcmaster. I just rebedded my bow cleats and replaced my winches. All attached with 316 SS from Mcmaster.

 

[CaptDan]

It might be "challenging" to get some new hi-strength U-bolts made up on a one-off basis locally, IMHO. These are most likely forgings. From the picture of the failure point, there may have been an internal flaw, judging by what appears to be corrosion at the separation point.

Sidebar: I used to work in a plant, long long ago, that refined and produced zirconium castings and machining, although no drop forging was involved. They would X-ray and ultrasound the finished parts for internal flaws. Reading the printouts and finding small anomalies was quite challenging for the lab guys, as I remember.
:nerd:
Other than Navtec, I wonder how many other marine rigging companies anywhere have much experience with this sort of metal technology -- Wichard comes to mind.

Grim photo!


Loren

Yeah, good point. I read someplace that Garhauer does custom fittings, but have no personal experience.

Capt Dan G>E35II "Kunu"

 

[CaptDan]

I don't know from what type of boat Maine Sail's pictures are from, but most 80's vintage Ericsons use the same type of attachment for the shrouds, instead of traditional chainplates. Underneath the eye there is a tie-rod leading to the TAFG.

Well, as you can see, I'm still stuck in the '70s. I didn't associate that hardware with the tie rod/TAFG system in later vintage boats. Thanks for cluing me in.

Capt Dan G>E35II "Kunu"

 

[Emerald]

Looking at McMaster here:

http://www.mcmaster.com/#ansi-specification-u-bolts/=1q5bdj

makes me really wonder about strength. They have square ones, but would guess that they are too small based on the thread dimension and working loads given. What is the thread and other dimensions on the broken part? I assume beefier than what is listed at the bottom of the above link.

 

[tenders]

This is interesting. Why is the 316 grade cheaper than the 304 for items for which equivalent sizes are available in the same part?

 

[ted_reshetiloff]

Did your buddy try Wichard? They still make these "Forged" U bolts. Very important that they are forged as I would be suspect of "Cold Bending" , but I'm no machinist either.

 

[mherrcat]

Same system as on my 30+. I am curious how the stud part attaches to the "U" part. Is it welded or is the fitting a single piece of metal?

 

[Chris A.]

He did try Wichard with no success. Not sure about Navtec though. Here is a picture of the newly fabricated fitting (sorry low res)

 

[treilley]

The problem with this type of fitting are the weak points in the design. Any sharp corners are more likely to break evidenced in the original failure. The new design has 2 sharp breaks now. That shoulder should have a nice smooth entry and exit. The deck skin can alway be chamferred to allow good seal against the shoulder.

 

[Emerald]

How were the shoulders made? Am I seeing signs of heat at the top of the threads? Wondering if the area was welded up and then turned down to make the shoulder? Always worried about changing the temper on something like this if heating has occurred. What is the wire size of the shroud attaching to this? Trying to get a feel for the loads involved. Thinking this should be at least on par with the breaking strength of the shroud, which is probably over 5000 lbs.

Here's a link to Loos and some cable specs. We'd be looking at 1x19 wire rope, probably 7/32 or larger for lower shrouds, and 1/4 or larger for uppers (based on my rig):

http://www.loosco.com/page23.htm

 

[ted_reshetiloff]

Sorry wichard makes these but not the right dimension for Ericson's. You need to contact Rig Rite. www.rigrite.com they can help you with replacements. I would be very suspect of something not forged. These things take one hell of a load...

 

[Chris A.]

My friend reported no joy from Rig Rite on the U bolts and I can say from personal experience on a spar replacement that they are next to useless from a service standpoint, even if they are the OEM supplier for Kenyon parts.