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-   -   Chain plates are out, now what? (http://www.sailnet.com/forums/gear-maintenance/39513-chain-plates-out-now-what.html)

jrd22 12-28-2007 11:42 PM

Chain plates are out, now what?
 
I've taken the chain plates out (well, almost)of the new to me 1988 Brewer 40 per the surveyors recommendation and I'm wondering how I check them, or where I take them to be checked for cracks, corrosion, etc. They look perfect, bright and shiny and smooth, but they are 20 years old (I think). Should I just have new ones made and not have to worry about them, or if they check out OK are they as good as new? I'm in Anacortes/Seattle area. Thanks, John
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Sasha_V 12-29-2007 12:30 AM

Why did the surveyor ask to have them pulled? That is most unusual, unless he detects a fault or a condition that makes a fault very likely. Are these ALL the chainplates or just the shrouds?

More info would definately be a good.

Okay, with my "I make Satinless hardware" hat on I can tell you that testing your chainplates properly is going to cost more then replacing them is likely to. In the end the best test is unfortunately a stress destruction test....that is sort of a one way trip. And when dealing with old parts, you test EVERY part and not just a sampling as you do with new ones.
X-ray bombing the chainplates for cracks will not give you a true picture of whether they are ready to fail or not, it will just eliminate or confirm one possible cause. Bad odds.

Dip and paint tests that allow chemicals to interact with the surface and reveal things are even less reliable then x rays...but they are way cheaper and easier and if there is a major issue, it will surely show up...if there is a medium issue or a collection of minor issues waiting to domino, you're out of luck.
(Isn't it comforting to hear this info from someone that used to weld and test 300atmosphere pressure vessels the size of an office building and radioactive containment systems?)

I have no idea why your surveyor wanted you to drop the rig and rip off all the chainplates, but having done it...go to the extra expense of fitting all new ones, with the right bolts, backing plates and everything. check for hull deformation and abrasion/collapse in the areas that were covered by the chainplates, It will cost you a few hundred dollars all up...it will buy you 40+ years of peace of mind regarding that particular thing going wrong...and it will maybe stop some of those annoying mystery leaks through the deck, too.

In truth, though...99% of the time when something in the area of a chainplate fails, it is the terminal, pin or swage plugged into the chainplate, and not the plate itself. Cheerful thought, no?

Best of luck and congrats on your new purchase. I am sure you will enjoy your time on the water with your own boat immensely.


Sasha

sailingdog 12-29-2007 09:44 AM

If you've already got the chain plates out... it would make sense to replace them, given that the current ones are 20 years old.

I'd have to agree with Sasha as to question why your surveyor told you to do this—unless there was some serious indications of problems with the chainplates or a known history of problems with them on this specific make of boat, 20 year old chain plates are probably still quite serviceable.


It would also be good to make sure that all the fastener holes for the chainplates, if they go through plywood or cored deck material, are properly potted and sealed against water intrusion.

CharlieCobra 12-29-2007 12:05 PM

Where did ya find yard space for this? I've been waiting for space to open up for two months now.

camaraderie 12-29-2007 12:24 PM

I've NEVER had a surveyor tell me to remove my chain plates. WHY did he suggest this? Were the pin holes elongated? Was there evidence of leakage around them? Were there rust cracks? There must be an underlying reason for that recommendation.

sailboy21 12-29-2007 12:26 PM

Does seem odd to pull chain plats for a survey. They are through deck type right? You can use a dye penetrate test, but as said before results are anything from conclusive. Any other testing is expensive. All commercial rigging is tested to a point above its rated working load, and retested at an interval. Never heard of this done on sailboat parts, could be interesting. Unless there is obviously something wrong, chain plates seem like they would be the last item of concern on the rig. The safety margin built into them is larger than any other rigging component.
My boat had a crack in the stainless cranze iron, surveyor just pulled me aside and told me to make sure the owner replaces that before I paid for the boat.

FrankLanger 12-29-2007 02:09 PM

Wait a sec, folks. While I don't really disagree with your posts above, and would also wonder why the surveyor suggested pulling the chainplates, there are lots of cases (and frightening pictures) of chainplates that looked fine above deck, but had corroded significantly at the part that is "inside" the deck, where moisture can get trapped and gradually corrode the chainplate. It could be that the surveyor had seen one like this recently, and was being a bit cautious, suggesting that pulling them is the only way to know if that section of the chainplate is deteriorating.
I agree with the above posts that now that you have pulled them, it is probably best to replace them with new ones, as then you won't have to worry about them for a very long time.
But I wouldn't want you thinking that the surveyor was necessarily wrong in his suggestion, or that you were wasting your time in taking them out--better safe than sorry, as losing one of these may cause the mast to fall at an inopportune time.
Frank.

jrd22 12-29-2007 09:30 PM

The only reason I can think of for the surveyor to require the chainplates to be removed is that I mentioned that the only other boat like this that I have seen advertised has had the chainplates replaced? I know that a lot of well know riggers recommend replacing chainplates every 10-12 years if you are cruising full time offshore in tropical climates, I don't know if that is overkill or not. It was not as big a job as I feared, boat was well made with good access to all under deck hardware(backing plates on everything. I only had to cut out one piece of plywood behind the stove that is hidden by a piece of stainless to access genoa track nuts and stanchion bolts(I'm taking the teak decks off also). I guess I'll plan on having new ones made, might run it by a local rigger. We are doing a fairly major refit; bottom paint strip and re-paint, hull painting(Awlcraft), remove teak decks, re-glas the decks and non-skid, replace head, some electronic upgrades, furling on headstay and inner forestay with sails for both, new batteries, new canvas all around, new upholstery, diesel forced air heat system, new liferaft. I'm not doing all of it myself, my job get's in the way of a lot of important stuff!

Charlie-you gotta know the right people! I'm hauled out in Anacortes at a guys place that has done a lot of work for me before.

John

pigslo 12-29-2007 09:36 PM

I would replace them while they are out as you have already done the hard part!
pigslo

camaraderie 12-29-2007 09:52 PM

Hey Pigs! Good ta see ya!! Happy New Year!


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