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Thread: Backstay Chainplate Discussions [pg 152 in Manual]

  1. #31
    Join Date
    Sep 2001
    Location
    Orinda, California
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    2,266
    We're considering it, but need to discuss the details with a rigger. Ebb is also considering and has a pair of cast bronze backstay chainplates ready do go. I believe there may be a photo of them on the thread "Ebb's Photo Gallery."

    There is also more discussin of this in earlier posts.

  2. #32
    Join Date
    Sep 2001
    Location
    Santa Cruz, California
    Posts
    453

    Question Chainplate material, size and Bay Area source

    In the midst of what is becoming an accident-caused rig re-fabrication project, I figured that I might as well pull the chainplates given that the rig is down and all. Pulling those forty-year-old suckers was all that pulling chainplates is promised to be. About half the bolts twisted apart when I as removing them. A view of the first photo below will show you why. Most of some of the bolts were pink. This occurred mostly on my aft lowers, which must be removed and reattached twice per sail due to the tabernacle, and so they probably have leaked more water than the other chainplates.

    The chainplates themselves seem to be in pretty good shape although beneath the green corrosion is a layer of reddish metal (colloidal copper I presume). In the second photo you can see that red color. The top and bottom chainplates in the second photo have been buffed up a bit with a nylon drill brush and the middle chainplate is it looked upon removal. You can still see the polysulfide band where the chainplate passed through the chainplate cover.

    You can see some bright spots where the bronze is shining through. A wire brush head did not get this red stuff off, but for some reason the nylon brush head did to some degree. These appear to be original chainplates, and if so, they are forty years old or thereabouts. I don't see any cracks or excessive wear, but the condition of some of the bolts and the fact that about 25% of the bolts that were bronze in color throughout sheered off upon removal, I think that I may replace the chainplates as well as the bolts.

    Removal time was four hours from start to finish working alone. Don't do it that way. It's a pain to be workign alone when the bolt head is on one side of the closet bulkheads and the nut is on the other.

    Now the questions:

    1. If these bronze 3/16 chainplates lasted forty years, why not have new bronze chainplates fabricated?

    2. Would it be better to used stainless steel chainplates for strength even though stainless tends to degrade in wet oxygen-deprived environments, like sometimes-leaking deck cores?

    3. If stainless steel is the way to go, should I go with 304 for strength or 316 for corrosion resistance? My backstay chainplate is 304 stainless.

    I did do a search on “chainplate” and “chainplates” on this forum but found that the discussion on the various links provided in the search did not address these questions. By the way, the search function is working very well now. Thanks Bill and Bill II.

    I intend to grind a bit of damaged wood from the deck core surrounding the chainplate slots and screw holes and fill the deck voids, chainplate solt and screw holes with epoxy. I will then drill and cut new holes before mounting my new chainplates or the current refurbished plates in the event that after final clean-up and inspection by a rigging wizard, the existing chainplates still appear to be serviceable.

    I have received two quotes for new 316 chainplates and they range from $60 to $80 each. Ouch!

    So does anyone have a source of bronze or SS chainplates in the Bay area? Or is any manufacturer anywhere still making the plates installed in our Ariels/Commanders?
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    Last edited by Scott Galloway; 09-15-2004 at 11:11 PM.
    Scott

  3. #33
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    Sep 2001
    Location
    Santa Cruz, California
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    453
    Here are the chainplates. Again, the top and bottom plates are buffed up a bit: The Bottom one more than the top. The shiny areas on the bottom plate are bronze-colored in real life, but the red-colored areas are just as red as they appear in the photo. Hmmmmm.

    I do like bronze for this applicattsion. The chainplate covers are bronze and servicable, and replacing them with stainless would add to the expense of the project, although I suppose I could use stainless chainplates with bronze plate covers. They are separated pretty well by polysulfide bedding compound.

    Any thoughts?
    Attached Images  
    Last edited by Scott Galloway; 09-15-2004 at 10:32 PM.
    Scott

  4. #34
    Join Date
    Jan 2004
    Location
    Scarborough, Maine
    Posts
    1,436
    Found this thread whilst "searching" and thought I'd add another pic of another woefully inadequate Backstay Chainplate. The knee looks OK, but as CP pointed out, inside the lazaret it is open on the top and subject to water coming in from the chainplate opening in the toe rail.
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    Last edited by mbd; 07-17-2006 at 06:15 PM.
    Mike
    Totoro (Sea Sprite 23 #626)

  5. #35
    Join Date
    Jan 2004
    Location
    Scarborough, Maine
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    Here's the bugger that was keeping me from removing the chainplate...
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    Mike
    Totoro (Sea Sprite 23 #626)

  6. #36
    Join Date
    Mar 2006
    Location
    Havre de Grace, MD
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    207
    best you could have hoped for is what happened with that retired bolt (twist in half)
    #97 "Absum!"

  7. #37
    Join Date
    Jun 2002
    Location
    Portsmouth, Virginia
    Posts
    142
    I replaced the bent over backstay chainplate on my Commander with one that I had made from thicker stock marine grade stainless steel(Navy scrap).A Pearson Tritan had rode up the backstay bending over the chainplate and also destroying the pulpit during Isebel which sank or damaged many boats at the yard. Just think about how strong that single backstay is to take that much damage. I had the new chainplate made an inch or so longer with an extra bolt hole. There are some pictures of the damaged stay and of the new one on this site somewhere. Why go to a split backstay? In addition the old insulator is still good as new. The 26 Pearson that I now have has a split backstay because of the motor well. When I get around to it I plan on replacing the backstay on my Commander with one that has an adjustable tensioner. I will try and keep the old insulator it seems to be stronger then the new ones that I have looked at.
    Last edited by Robert Lemasters; 07-18-2006 at 01:45 PM.

  8. #38
    Join Date
    Sep 2001
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    Asst. Vice Commodore, NorthEast Fleet, Commander Division (Ret.) Brightwaters, N.Y.
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    1,823
    Anybody else have a larger (7/16 vs 3/8 inch) turnbuckle on the backstay? Not sure why my boat did.

    Nice rig tuning here
    Attached Images  

  9. #39
    Join Date
    Sep 2001
    Location
    Hampton Roads Va.
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    821
    What were you doing on a Hunter ?

    Saw the same thing on Bluenose II foremast .

  10. #40
    Join Date
    Mar 2006
    Location
    Havre de Grace, MD
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    207
    I think he was going for that high tech sail shape . . .
    #97 "Absum!"

  11. #41
    Join Date
    Jan 2004
    Location
    Scarborough, Maine
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    1,436

    Thumbs up Upgraded Chainplate

    I just got this back. This is the replacement for the one in post #28. The original was flattened to make the template for the new one. I'm confident in saying, my Backstay Chainplate will no longer be the weak link back there. It was made with 316 stainless. A couple of more holes were added as per the manual also...
    Attached Images  
    Mike
    Totoro (Sea Sprite 23 #626)

  12. #42
    Join Date
    Apr 2002
    Location
    Houston, Texas
    Posts
    290
    Mike, looks like the one I had made, real beefy!!
    Kent

  13. #43
    Join Date
    Jan 2004
    Location
    Scarborough, Maine
    Posts
    1,436
    Hey Kent, you got any pictures/pointers on your installation?

    PS. The heat up here this week reminds me why I moved from Austin a few years back - only there's no AC to retreat to up here! Yuck!
    Mike
    Totoro (Sea Sprite 23 #626)

  14. #44
    Join Date
    Sep 2001
    Location
    Santa Cruz, California
    Posts
    453

    Question

    Here is a question on the backstay chainplate. I had a new backstay chainplate made and I installed in 2002. It was made from 304 stainless and is pretty beefy. The argument for 304 at the time was that it was stronger than 316 stainless, which is true apparently, until it corrodes. I want to eventually replace it with 316 stainless, since the darn thing seems to be rusting in the salty lazarette environment. To date, the rust seems to be superficial, so I have not been in a hurry.

    All seemed well for four years, but after a couple of days of heavy wind (30-35 mph) last month, I noted that the backstay chainplate cover had risen somewhat at the forward end. I removed the screws, cleaned the chainplate cover and chainplate of old polysulfide caulk and superficial rust and rebedded the cover. The cover slipped very nicely back over the chainplate, but the screws that hold the cover to the fiberglass deck now seem to be somewhat forward of the original holes in the fiberglass deck. They fit in the holes, but at an angle sloping aft from top to bottom.

    So this is a concern to me. I took the boat back out on a 30- 35 mph day and sailed lose hauled and on a broad reach in four foot swells both unreefed and later double reefed, and the plate popped up in front again slightly. The front screws are loose in their holes, so they are not really holding in the deck, but there must still be some upward or forward pressure to pop the plate up, and to have moved the plate forward slightly so that the screws are no longer vertical. I can't recall for sure whether the screw holes were actually vertical in 2002, but I can say that the cover has never popped up before. If the width of my (new in 2002) backstay chainplate was slightly greater than the original, the screw holes would not have aligned.

    Inspection below tells me that the backstay chainplate still seems to be well secured to the knee with the original three bolts and two additional bolts that I added at the time of installation in 2002. One of these additional bolts runs through an extension that I glassed on to the top of the knee. The extension seems to be solid. So all seems well below, but yet the chainplate must have somehow bent forward or slipped forward slightly. For four years this was not a problem. Now I seem to have a problem. Or do I?

    In intend to remove and inspect the chainplate and then order new one made from 316 stainless and of thicker stock, but I am curious about why this might happen, as the thickness of my 304 stainless steel chainplate is substantially greater than what was there originally.

    I replaced the original based on the experience of others on this forum and the recommendations of the Ariel Manual. A thicker chainplate seemed to be in order. My original chainplate, scrawny though it was, was not deformed in any way. The new chainplate was supposedly cut out of 304 stainless using the original as a template, so the width, length and forward to aft sloping angle of the top section should be the same as the original. Any thoughts?
    Scott

  15. #45
    Join Date
    Sep 2001
    Location
    Orinda, California
    Posts
    2,266
    Quote Originally Posted by Scott Galloway
    . . . but yet the chainplate must have somehow bent forward or slipped forward slightly. Any thoughts?
    From our experience tuning the boat for racing, I've found that the tightened backstay will pull the chainplate forward. I don't believe it's moving where attached to the knee. The bolts and all are fine. Rather, the stern portion of the hull may actually be "bending" a bit from the stay's pulling force against it. As noted in the manual, probably the real fix is to reinforce the weakest part of the boat -- its stern.

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