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Chainplates

Just acquired a 1978 Crealock 37. Chainplates look good but I know they are going on 40 years old. Is it possible that they could still be trustworthy?
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Re: Chainplates

At 40 years old not really. Even if they aren't corroded they have been work hardened to the point I wouldn't trust them anymore.
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Re: Chainplates

Only way to know for sure is to pull them off. If you have any design on offshore sailing then it is prudent to replace them. Standing rigging as well. All this before the huge inverter, watermaker, A/C, and the other luxury items. Might pull the mast too and give it a good going over. How's that rudder doing? Thru hulls? Sails? The important stuff that will keep you out here. Good luck.
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Re: Chainplates

That's a item that is addressed in the Westsail maintenance manual and like aeventyr60 says pull it and find out . However , are there rust stains around the chain plates ? If not I wouldn't worry about it to much . Does the Crealock 37 have a history with problem chain plates ? Westsails have problems with the boomkin tangs for one thing they get under water and the early ones weren't wide enough they rusted and cracked around the thru bolt . But you just got the boat , enjoy it and watch stuff .
Awesome boat ! CREALOCK 37 (PACIFIC SEACRAFT) sailboat specifications and details on sailboatdata.com

PS welcome to Sailnet hope to hear more about you and the boat .
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Last edited by Markwesti; 4 Weeks Ago at 10:12 PM.
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Re: Chainplates

I have a 38 year old boat with extremely solid chain plates, and supposedly a reputation for bad chain plates, but she has spent about 28 years in fresh water, hauled out and covered for 6 months a year for most of those 28. I think it depends.

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Re: Chainplates

Replace them. Be safe. Its a seriously fantastic boat. I'm envious. But don't risk your rig on 40 year old bits of metal that have almost certainly brittled over the years. And as others have noted...check out those thru hulls, seacocks, and of course the standing rigging.

1. Make sure it keeps floating.
2. Make sure the rig doesn't fall down.
3. Make sure the keel doesn't fall off.
4. Sail.
5. ???
6. Profit!
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Re: Chainplates

Enjoyed your response. The plan is to leave in four years. In the meantime, I spent all my money and more, so I have to enjoy it. Eventually, I will heed advice and pull plates. I will sail it in SF Bay and thereabouts to get my skills down and to see what falls apart. It is dry and solid thus far and manageable for me.
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Re: Chainplates

You might want to open the Search This Forum box, type in chainplates, and look at some of the past Pacific Seacraft threads on the subject. Among them is chainplate followup

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Re: Chainplates

I replaced 9 chainplates from my boat. Not because I saw anything bad, but other owners of similar boats have and I wanted to make sure mine were good. When I went to remove the last one from the boat, it bent in my hand and cracked wide, at a point where only one bolt was essentially holding a stay to the boat.

Once off the boat, I bent it a little more and it broke. 1/4" thick piece of metal.

Here, you can see how bad it was, and there was no visible sign of failure before it was pulled.

Replace and have piece of mind. Better than having a failed rig while at sea.
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Re: Chainplates

The stainless steel typically used for chainplates has a 'severe' lower limit of fatigue endurance. Most 300 series stainless will have a fatigue endurance limit of 30% ultimate tensile strength ... UTS at about 90,000 psi. OR a Fatigue Strength at only 30,000 psi.
What this means is that if the chainplate is strained beyond/above 30% of UTS (loading to or greater than 30,000 psi), it will begin to rapidly fatigue; if kept below 30% UTS it will be virtually indestructible vs. 'fatigue'. If possible, always 'oversize' (thickness) when possible.

For the "blue water" typical design which (should) includes an inbuilt 3:1 Safety Factor ... historical 'scantlings' will show that NEW chainplates should have a high probability of successful service for ONE circumnavigation - about 25000+ sea miles.
For the typical 'coastal' design with a 2:1 inbuilt factor of safety - about 2/3 of ONE circumnavigation or 17000± sea miles, then a high probability of failure thereafter.
Fatigue Endurance limit for 300 series stainless is: 1,000,000 'load cycles' that exceeds 30% of Ultimate Tensile Strength .... on a blue water boat this load cycle max. occurs at ~40-45° angle of heel. On a 'coastal' design ... about a ~30° heel angle.
Even with new chainplates, once you accumulate 1 million load cycles at or above 30% UTS, there is a high probability of sudden catastrophic fatigue failure.

Crevice corrosion - an ADDITIONAL failure mode that WILL shorten the service life and reduce the load bearing value. Even when the stainless is being formed in the mill, micro-cracks will be formed. These cracks, plus cracks due to additive fatigue cracks will begin to form internal corrosion of the metal - thus an additional weakening and besides any simple accumulation of developing fatigue.

Suggestion for long distance sailing:
• For any boat with an unknown in-service life ... replace the damn chainplates.
• For any boat with chainplates over ~12 years old ... replace the damn chainplates.
• For any boat with chainplates - that have a 'designed' KINK or 'bend' in them ... replace at ~8-10 years.
• For any chainplates that have 'multiple' holes for bolting to knees, hull, etc. ... pull them off and inspect them for small/teeny cracks inside the bore holes that emanate perpendicularly from the axis of strain (looks like a 'smiley face' ... | -O- | ) replace immediately.
• Immediately replace any studs or bolts that have developed 'rusting', especially 'blackish'/dark rusting. Ditto, any chainplate that has developed 'zones' of black rusting. Ditto, for any polished chainplate that has developed a zone of noticeable 'dullness'.
• Inspect 'old' chainplate studs/bolts with a torque wrench ... torque to about 60-70% of the maximum torque value for the bolt or stud. If any 'break off' at or below ~60-70% torque value ... replace ALL of them for that 'station'.

Life extension of new chainplates.
• Suggest that you use 316 SS .... if you can afford it, get your 316 with "MILL SPECIFICATIONS" for 'chemicals and physicals' (so that you're 'sure' that you're not buying 'crap').
• POLISH the entire chainplate to a mirror-like surface. If you have the extra-$ available, then have the already mirror-polished chainplates - 'electro-polished'.

hope this helps.
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Last edited by RichH; 4 Weeks Ago at 12:56 PM.
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