- Aug 10, 2010
- 106
I guess. But yeah I'm in the process of replacing. Would be really interested to find a place to test the old ones to failure...side project for winter I guess.
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Our Cherubini Chainplates Are 40+ Years Old -- Any Failures?
- Thread starter rardiH36
- Start date
chichiflyes:
Motivated by your findings, I pulled both my center (cap shroud) chainplates today. Same dimensions as you cited for your lower aft chainplates -- 37.0" overall and 35.5" on centers. I used stainless steel scouring pads, then "Spotless Stainless" to remove the minor surface discoloration/rust spots.
On inspection, I found a couple of areas of almost imperceptible surface pitting. Using a Dremel diamond fitting, didn't take much to reveal clean metal. Probably 1/64" was all I took off ... likely less. No sign of crevice corossion cracking was evident anywhere. So I have no concerns about continuing to use the center chainplates. Although when they go back in, I will reverse them. The bottom instead will be up. Let a new section reside in the deck core under the cover plate for the next few decades!
Interestingly, the pitting was further down, well inside the boat rather than at the deck core. And mostly was underneath what appeared to be very old remnants of clear packing tape. The kind with the fiber strands running through. I am thinking Hunter's fabricator used the tape to bundle several chainplates together for ease of shipping. And the installer didn't remove all the tape installing on the boat. I have read that SS crevice corrosion usual happens where salty water becomes trapped against the steel.
With the two chainplates out, I poked at the deck core with a small screwdriver. Was solid!
Only took a couple of hours to remove the two chainplates. After I re-install them, I will remove the others in sequence for a look-see. For peace of mind.
Motivated by your findings, I pulled both my center (cap shroud) chainplates today. Same dimensions as you cited for your lower aft chainplates -- 37.0" overall and 35.5" on centers. I used stainless steel scouring pads, then "Spotless Stainless" to remove the minor surface discoloration/rust spots.
On inspection, I found a couple of areas of almost imperceptible surface pitting. Using a Dremel diamond fitting, didn't take much to reveal clean metal. Probably 1/64" was all I took off ... likely less. No sign of crevice corossion cracking was evident anywhere. So I have no concerns about continuing to use the center chainplates. Although when they go back in, I will reverse them. The bottom instead will be up. Let a new section reside in the deck core under the cover plate for the next few decades!
Interestingly, the pitting was further down, well inside the boat rather than at the deck core. And mostly was underneath what appeared to be very old remnants of clear packing tape. The kind with the fiber strands running through. I am thinking Hunter's fabricator used the tape to bundle several chainplates together for ease of shipping. And the installer didn't remove all the tape installing on the boat. I have read that SS crevice corrosion usual happens where salty water becomes trapped against the steel.
With the two chainplates out, I poked at the deck core with a small screwdriver. Was solid!
Only took a couple of hours to remove the two chainplates. After I re-install them, I will remove the others in sequence for a look-see. For peace of mind.
- Aug 10, 2010
- 106
Rardi - that’s encouraging news. I hope the rest of mine are Ok….Once I have the new plates fabricated (shop is making them soon) I plan to tackle the forward lowers, then the uppers. I‘m having the new ones made from 3/8” thick stock and am foregoing the welding of washers at the ends to increase the thickness where the pins and bolts attach - this was at the recommendation of the rigging shop as they didn’t like the weld area of the washers at each end -claiming it could be a good place for corrosion to start since the welds aren’t as smooth as plain steel. The 3/8” thick plates are almost as thick as the ends of the original, but the overall strength is increased (Although that’s likely not needed…) I’m going with 316SS vs. the original 304.
On the port side where the core had rotted between the chain plate slot and deck fill, I was able to scoop out about 90% of the bad core and simply pumped in some thickened epoxy. Not a text book repair, but since it was such a small area that was compromised, it should be more than adequate for strength. I then fabricated some 1/4” G-10 plates that will be bonded to the deck where the chain plates pass through. This will provide a slightly larger area for sealant to bond to the chain plates. Hopefully keeping it dry.
I also removed and cleaned the 1/4”x2”x5” straps that connect the chain plate to the hull inside the boat. There is a 1” bolt at the bottom that goes through the massive stringer and a 1/2” bolt at the top for the chain plate end. I also had some pitting on one of those smaller straps on the starboard side. I ground down a good bit to find clean metal. I plan to soak all those pieces with a warm citric acid bath….seems like an easy task that may benefit those parts.
On the port side where the core had rotted between the chain plate slot and deck fill, I was able to scoop out about 90% of the bad core and simply pumped in some thickened epoxy. Not a text book repair, but since it was such a small area that was compromised, it should be more than adequate for strength. I then fabricated some 1/4” G-10 plates that will be bonded to the deck where the chain plates pass through. This will provide a slightly larger area for sealant to bond to the chain plates. Hopefully keeping it dry.
I also removed and cleaned the 1/4”x2”x5” straps that connect the chain plate to the hull inside the boat. There is a 1” bolt at the bottom that goes through the massive stringer and a 1/2” bolt at the top for the chain plate end. I also had some pitting on one of those smaller straps on the starboard side. I ground down a good bit to find clean metal. I plan to soak all those pieces with a warm citric acid bath….seems like an easy task that may benefit those parts.
chichiflys -
Good work around the chainplate cover plates on deck. I am sure that your epoxy core repair will be more than adequate. Here on SF Bay, aside from the winter rains, humidity is generally low and we don't have freezing winters. So thaw and freeze of water isn't a factor towards core rot. The only area I've had to deal with is the small section in the cockpit under the pedestal. The area was soft when I bought the boat. Thinking that the core was totally rotted, I removed the pedestal and the guard. Cut at the non-skid to smooth interface to remove the top skin. Only to find absolutely no rot! Instead, the some of the layers of the plywood core had separated. The plywood was still firmly attached to the lower and outer skins. Hunter used high grade plywood which was green in color. I think pressure-treated? Took me forever to chisel and power-tool the plywood off the upper and lower skins -- which I needed to do before laying down new wood and flooding with epoxy. And finally, reattach the top skin that I removed. If I had known in advance, I instead would of drilled a dozen or so 1/4" holes down through the core but not all the way through. Then injected thin epoxy into each whole. Found some sort of tool that could vibrate the surface so the epoxy could flow around into the separated layers. I could have saved days of work!
Back to the Cherubini 36 chainplates:
- Curious -- what did the rigging shop say about the original chainplates? The one in your photo looked bad. But any actual cracks found?
- I did reinstall my middle (cap shroud) chainplates today. The starboard one went real quick. The port one not so much. It is more recessed behind the teak cabinetry. So access with two hands was awkward. And something was just a little off with the alignment. I discovered this during the removal as well. The bolt just didn't want to back out. Nor did it want go back in without a lot of forceful jiggling.
- For the aft chainplates, we have plenty of room at the hull anchor location to use both hands at the same time. So getting the eight/ten (or so) spacing washers back over the bolt is doable. But a tip for when you do your middles: Using just a couple of drops of super-glue between each washer, I stacked four of them together to make one thicker unit. I wouldn't have been able to get all those washers back over the bolt without this step.
- I took a look at my anchor points for the two forward chainplates. The port side is inside the closet. Unfettered access. The starboard one though looks impossible. For one person anyway. The anchor point is under the head's sink counter. Only one arm can reach in through the cabinet door underneath. Just barely. Tool use and manipulation will be impossible. Access is better/closer through the wood hatch cover just to the left of the sink. But again only one hand at a time can get in. If my port forward chainplate passes muster, I will assume the starboard is also good. Won't bother to pull it!
Good work around the chainplate cover plates on deck. I am sure that your epoxy core repair will be more than adequate. Here on SF Bay, aside from the winter rains, humidity is generally low and we don't have freezing winters. So thaw and freeze of water isn't a factor towards core rot. The only area I've had to deal with is the small section in the cockpit under the pedestal. The area was soft when I bought the boat. Thinking that the core was totally rotted, I removed the pedestal and the guard. Cut at the non-skid to smooth interface to remove the top skin. Only to find absolutely no rot! Instead, the some of the layers of the plywood core had separated. The plywood was still firmly attached to the lower and outer skins. Hunter used high grade plywood which was green in color. I think pressure-treated? Took me forever to chisel and power-tool the plywood off the upper and lower skins -- which I needed to do before laying down new wood and flooding with epoxy. And finally, reattach the top skin that I removed. If I had known in advance, I instead would of drilled a dozen or so 1/4" holes down through the core but not all the way through. Then injected thin epoxy into each whole. Found some sort of tool that could vibrate the surface so the epoxy could flow around into the separated layers. I could have saved days of work!
Back to the Cherubini 36 chainplates:
- Curious -- what did the rigging shop say about the original chainplates? The one in your photo looked bad. But any actual cracks found?
- I did reinstall my middle (cap shroud) chainplates today. The starboard one went real quick. The port one not so much. It is more recessed behind the teak cabinetry. So access with two hands was awkward. And something was just a little off with the alignment. I discovered this during the removal as well. The bolt just didn't want to back out. Nor did it want go back in without a lot of forceful jiggling.
- For the aft chainplates, we have plenty of room at the hull anchor location to use both hands at the same time. So getting the eight/ten (or so) spacing washers back over the bolt is doable. But a tip for when you do your middles: Using just a couple of drops of super-glue between each washer, I stacked four of them together to make one thicker unit. I wouldn't have been able to get all those washers back over the bolt without this step.
- I took a look at my anchor points for the two forward chainplates. The port side is inside the closet. Unfettered access. The starboard one though looks impossible. For one person anyway. The anchor point is under the head's sink counter. Only one arm can reach in through the cabinet door underneath. Just barely. Tool use and manipulation will be impossible. Access is better/closer through the wood hatch cover just to the left of the sink. But again only one hand at a time can get in. If my port forward chainplate passes muster, I will assume the starboard is also good. Won't bother to pull it!
- Aug 10, 2010
- 106
Hello Rardi,
Thanks for that info and tip. Luckily the pedestal area appears solid on our boat. Although I did have some intrusion into the core on the aft starboard deck area above the quarter berth....drilled and filled for now since it's a small area of the deck, may tackle that appropriately some day?
Re the two plates - after cleaning I couldn't see any cracks per se - but the Rigging shop recommended replacement as did the surveyor. They agreed it wasn't terrible, but since you cant see what's going on inside the metal it was a safer avenue. While I am waiting for the plates to be fabricated I removed the two smaller "connector plates" (2"x5") where the main chain plate attaches inside the boat. The stbd side also had signs of pitting where they contact the large stringer/ridge of fiberglass around the 1" bolt. So I ground away and polished them as best as I could and then soaked them in a hot citric acid "passivation" solution (skeptical it'll help much). Replacing those may also be the best option, but since there are two of those plates I figured even if one begins to fail the other will prevent a catastrophic loss? Or that may be wishful thinking. I'll upload some pics of those this evening.
Instead of washer stacks our boat has thick plastic spacers sandwiching the chain plate between the two shorter plates at the bottom, so it's not too terrible to reinstall.
As far as access, my dad installed an AC unit in the port closet, so getting to that chain plate is a little awkward, but doable I think. And yeah the starboard forward chain plate will be fun..can't wait for the twisting, awkward neck strain that will surely make that a memorable time!
Thanks for that info and tip. Luckily the pedestal area appears solid on our boat. Although I did have some intrusion into the core on the aft starboard deck area above the quarter berth....drilled and filled for now since it's a small area of the deck, may tackle that appropriately some day?
Re the two plates - after cleaning I couldn't see any cracks per se - but the Rigging shop recommended replacement as did the surveyor. They agreed it wasn't terrible, but since you cant see what's going on inside the metal it was a safer avenue. While I am waiting for the plates to be fabricated I removed the two smaller "connector plates" (2"x5") where the main chain plate attaches inside the boat. The stbd side also had signs of pitting where they contact the large stringer/ridge of fiberglass around the 1" bolt. So I ground away and polished them as best as I could and then soaked them in a hot citric acid "passivation" solution (skeptical it'll help much). Replacing those may also be the best option, but since there are two of those plates I figured even if one begins to fail the other will prevent a catastrophic loss? Or that may be wishful thinking. I'll upload some pics of those this evening.
Instead of washer stacks our boat has thick plastic spacers sandwiching the chain plate between the two shorter plates at the bottom, so it's not too terrible to reinstall.
As far as access, my dad installed an AC unit in the port closet, so getting to that chain plate is a little awkward, but doable I think. And yeah the starboard forward chain plate will be fun..can't wait for the twisting, awkward neck strain that will surely make that a memorable time!
Hello chichiflys:
Today pulled the two aft chainplates. Brought them home to clean and then remove rust and do passivization with citric acid gel (Spotless Stainless). They are in fine condition. Can't see any evidence of stress cracking. Again, I will install them upside down to minimize future corrosion happening in the same chainplate area. (I have found however, that the 1/2" hole on the bottom isn't perfect. A little too small for the 1/2" pin at the bottom of the turnbuckle fitting. I think the reason is that the welded washers weren't aligned perfectly to the hole on the chainplate. Grinding the hole a smidgen bigger with a Dremel diamond bit did the trick. Only took a minute or two.)
As I described in a previous post, low humidity and mild temps here in the San Francisco area are probably a better environment to avoid problems ... as compared to the East Coast, US Gulf and Midwest lakes. Also I have been pretty good over the years at caulking the chainplates at the deck level to minimize H2O intrusion.
As previously reported, the two middle (cap shroud) chainplates have already been done and are OK. Now reinstalled.
Next up is the forward chainplate on the port side. If it OK, I will call it a day. And not attempt the almost impossible to reach with tools starboard forward.
Today pulled the two aft chainplates. Brought them home to clean and then remove rust and do passivization with citric acid gel (Spotless Stainless). They are in fine condition. Can't see any evidence of stress cracking. Again, I will install them upside down to minimize future corrosion happening in the same chainplate area. (I have found however, that the 1/2" hole on the bottom isn't perfect. A little too small for the 1/2" pin at the bottom of the turnbuckle fitting. I think the reason is that the welded washers weren't aligned perfectly to the hole on the chainplate. Grinding the hole a smidgen bigger with a Dremel diamond bit did the trick. Only took a minute or two.)
As I described in a previous post, low humidity and mild temps here in the San Francisco area are probably a better environment to avoid problems ... as compared to the East Coast, US Gulf and Midwest lakes. Also I have been pretty good over the years at caulking the chainplates at the deck level to minimize H2O intrusion.
As previously reported, the two middle (cap shroud) chainplates have already been done and are OK. Now reinstalled.
Next up is the forward chainplate on the port side. If it OK, I will call it a day. And not attempt the almost impossible to reach with tools starboard forward.
- Aug 10, 2010
- 106
Unfortunately my chain plates have likely been undisturbed for 15 years or so....so I'm paying the price of lack-maintenance in this area. Hope to have the new plates back today from the rigging shop. I haven reason to think the other four are not in better shape, so will likely get them fabricated and installed over the winter.
Clearly I need to improve my SS polishing tool set, but the inner, short plates came out OK for the first attempt. Not quit a mirror, but much shinier than what they looked like before. With any luck I'll have the two new plates in this weekend and perhaps a test sail on Sunday... thanks for the update Rardi!
Clearly I need to improve my SS polishing tool set, but the inner, short plates came out OK for the first attempt. Not quit a mirror, but much shinier than what they looked like before. With any luck I'll have the two new plates in this weekend and perhaps a test sail on Sunday... thanks for the update Rardi!
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- Aug 10, 2010
- 106
installed the two new plates. Worked out OK - almost didn't have enough room on the port side, the G10 plates I bonded to the deck reduced the margin for the shroud turnbuckle pin clearance. But they fit. Unfortunately the cost went up considerably as the shop had to remove a lot more mill finish from the stock plates when they came in....passing that cost onto me. Doubt I'll use them again for the remaining 4.
Rardi - by chance did you measure the other plates when you removed and reinstalled them. I presume they are all 37" overall. It's about what I get when I try to measure the plates that are still in the boat, but of course have to estimate the deck thickness. If so, I will be comfortable having a new shop fabricate 4 more based on the measurements of the original plates.
I still need to finish up soma painting to pretty up the area, but they survived heavy rain and heavy water hose testing....used butyl tape to seal them off.
Test sail yesterday in 15knots southerly breeze went well, mast is still on the boat!
Rardi - by chance did you measure the other plates when you removed and reinstalled them. I presume they are all 37" overall. It's about what I get when I try to measure the plates that are still in the boat, but of course have to estimate the deck thickness. If so, I will be comfortable having a new shop fabricate 4 more based on the measurements of the original plates.
I still need to finish up soma painting to pretty up the area, but they survived heavy rain and heavy water hose testing....used butyl tape to seal them off.
Test sail yesterday in 15knots southerly breeze went well, mast is still on the boat!
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chichiflys,
Just saw your post. Needed a break from up on the ladder painting the side of my house!
I think I already posted that the middle cap shroud chainplates are the same length as the afts. Namely 37" overall. And 35.5" between the centers of the holes. I had my port side forward chain plate out a couple of days ago. But completely forgot to measure it before reinstalling it. But if your year h36 setup is the same as mine with the port forward anchor point in the closet, it will be a straight measurement from the anchor point up to under the liner/deck. Make an estimate for the thickness of section you can't see. Plus add the section that is above the deck. Should be a good approximation if the overall length is again 37 in.
Upon removing my forward chainplate, at first I was alarmed. As there looked to be a crack. But on close inspection I think instead that the 1980 fabricator did not do a good job smoothing between the rough unpolished part and the nice shiny part. This was confirmed when I ground down just a smidgen with Dremel tool diamond bit. No evidence of any cracking when the surface was removed. And since I am reinstalling the chain plates upside down, and I can readily see the bottom in the closet, I will be able to observe any issues.
Just a thought, do you really need the new chainplates to be polished mirror perfect? Reinstalling my chain plates upside down (on purpose!) means the unpolished ends are now the sides up on the deck. After reattaching the standing rigging fittings, they look just fine. They may tarnish easier with surface rust overtime. If so, citric acid gel rust remover and passivatione will clean it up real fast.
Just saw your post. Needed a break from up on the ladder painting the side of my house!
I think I already posted that the middle cap shroud chainplates are the same length as the afts. Namely 37" overall. And 35.5" between the centers of the holes. I had my port side forward chain plate out a couple of days ago. But completely forgot to measure it before reinstalling it. But if your year h36 setup is the same as mine with the port forward anchor point in the closet, it will be a straight measurement from the anchor point up to under the liner/deck. Make an estimate for the thickness of section you can't see. Plus add the section that is above the deck. Should be a good approximation if the overall length is again 37 in.
Upon removing my forward chainplate, at first I was alarmed. As there looked to be a crack. But on close inspection I think instead that the 1980 fabricator did not do a good job smoothing between the rough unpolished part and the nice shiny part. This was confirmed when I ground down just a smidgen with Dremel tool diamond bit. No evidence of any cracking when the surface was removed. And since I am reinstalling the chain plates upside down, and I can readily see the bottom in the closet, I will be able to observe any issues.
Just a thought, do you really need the new chainplates to be polished mirror perfect? Reinstalling my chain plates upside down (on purpose!) means the unpolished ends are now the sides up on the deck. After reattaching the standing rigging fittings, they look just fine. They may tarnish easier with surface rust overtime. If so, citric acid gel rust remover and passivatione will clean it up real fast.
- Aug 10, 2010
- 106
OK thanks for the confirmation. Since they didn't produce many 36s, I have to believe Hunter Marine would have simply made all the chain plates the same size (cheaper and faster to do this) - and made up for any inconsistencies in length by adjusting where they drilled through the hull stringer for the inside mounting plates (large 1" hole)....but yeah, when I make an estimated measurement I come up with about 37" overall on the remaining plates.
And no - a mirror polish isn't necessary, but as you say it may stave off some surface tarnishing easier so I'll just keep it consistent. I found another shop who can fab four plates, just waiting for his cost estimate; hopefully it's a good bit less than the shop that made the first two!
Cheers,
Marc
And no - a mirror polish isn't necessary, but as you say it may stave off some surface tarnishing easier so I'll just keep it consistent. I found another shop who can fab four plates, just waiting for his cost estimate; hopefully it's a good bit less than the shop that made the first two!
Cheers,
Marc
- Aug 10, 2010
- 106
Still slowly replacing my chain plates. Did the two aft lowers last year. Got the port fwd lower a week or so ago. It was fine, but I replaced it. Removed the Stbd. fwd lower - WOW - about 50% failed. The odd thing is the corrosion crept it where the plate went through the shelf in the head, not where it went through the deck. The slot for chain plate in the head was very tight - certainly didn't need to be, and it had those SS cover plates as well, also not needed. It was a bear to remove, and when I did I noticed it was bent....then saw the crack. And we had just gone sailing earlier today (luckily winds were light)....so I still need to do the uppers, but will certainly knock those out ASAP before any more sailing this season. Yikes.
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Suggest you keep using the cover plates. They allow you to rebed the chainplates and when tightened down help to create a good watertight seal.
- Aug 10, 2010
- 106
Definitely - but they are only needed in my opinion on the deck....the OEM folks put them everywhere inside. I guess it looks better? But it doesn't help anything really.