Chain Plate and Bolt Inspection

[thomm225]

So after almost 12 years of sailing my old project boat, I have started inspecting the chain plates and bolts for them before I replace the rigging.

One had a vertical line in it so I figured it might be cracked.

It's very hard to tell but there is a hairline crack/line on the surface that is barely there, but as you can see in the photos the paint sort of told on it.

Opposite side is fine.

The 49 year old bolts, nuts, and washers just have superficial rust on them.

A friend that is also on CF says he can make me a new chain plate so I guess I'll replace it but the line/crack is barely there

I will reuse those 49 years old bolts though.

Has anyone else had these hairline surface cracks on their chain plates?

Mine are 1/8" it appears

Clevis pin on the turnbuckles look pretty bad though so they will all be replaced along with a few turnbuckles

[wholybee]

I hope/expect you are joking about reusing the bolts. Bolts are cheap. That little "superficial" rust around base of the head could result in a head suddenly leaving.

[thomm225]

Originally Posted by wholybee

I hope/expect you are joking about reusing the bolts. Bolts are cheap. That little "superficial" rust around base of the head could result in a head suddenly leaving.

No, I wasn't joking.

I have been very tight with money ever since I bought a 2 year old car in the 70's. I was 16 and made $1.00/hour

The payment was around $72.00/month.

Then I bought a boat for $300 soon afterward so I had no money.

Anyway nice shiny new bolts might be good to have so I'll reconsider.

I was very surprised to see this hairline rather superficial crack in that chain plate. It's only on the surface but I'm not an expert on SS.

It could be the beginning of a failure under heavy loads which I do put the boat under at times

[SomeGuyInaShirt]

I wouldn't dream or re-using those fasteners, how much is a rig failure going to cost? After so many years corrosion and metal fatigue has weakened those fasteners a lot. If you've already removed them, call McMaster Carr and get a quote at least.

[SailingHarmonie]

Reusing old 40 year old stainless steel bolts? That’s just crazy. How do you know there is not a stress crack at the root of one of the threads? You do NOT!!!

This is taking being cheap way beyond an affectation and past the point of folly.

If you always sail solo, it is just dumb. If you ever take other people sailing with you it is irresponsible. Sorry to be harsh, but that’s the case.

I have seen chainplate bolts break off at the nut from stress cracking. Literally, just fall off. No visible rust at all. That’s not what causes these failures.

[RaymondR]

From a metal fatigue viewpoint stainless steel is not a very reliable material and since a piece of stainless steel flat bar of sufficient length from which a replacement set of chain plates could be made using just a hacksaw, grinder and drill press I'd be inclined to replace bith the chain plates and bolts.

[Drunkonwatch]

don’t over heat the stainless if you fab them up helps in the long run.

[thomm225]

Thanks for the input.

I'll go ahead and replace the nuts and bolts on this one since they are out already and quite hard to get out as well, but may only replace the bolts I pull to inspect on the other ones.

I plan to ask and pay my friend to make/drill 2-3 new chain plates and replace this one with the possible hairline crack.

My rig is so over built though that even a bad bolt or two probably wouldn't cause a rig failure.

That would probably only happen with a weak swage, wire, or clevis pin, etc.

The clevis pins look bad so I'll replace those and the turnbuckles on the forestay and backstay plus on the uppers.

This boat has the full set of two lowers, and an upper shroud on each side attached to fiberglass knees plus forestay and backstay holding up a rather short mast with a low amount of sail area around 350 sq ft total

I'll also get input from my friend who has done refits on his old Alberg 30, a Cape Dory 25, a Westsail 32 (not extensive), and now is back to another Alberg 30 which I'm sure he will keep.

Since it's only February, I may pull and replace more bolts and chain plates since I just plan to do some touch up painting and replace the backstay. May replace the forestay soon but it looks a lot better than the backstay.

All stays will be replaced but I'll do it slowly with the mast up is the plan

Also ran a backup line to the mast to support the backstay which the main sheet and main halyard also do to some extent

[thomm225]

My friend said he replaced all his chain plates and the nuts, bolts etc. on his old Alberg 30.

So I'll at least do the possibly cracked chainplate (starboard side lower) and the chainplates for the uppers both sides plus nuts, bolts etc. for starters

[RaymondR]

Originally Posted by RaymondR

From a metal fatigue viewpoint stainless steel is not a very reliable material and since a piece of stainless steel flat bar of sufficient length from which a replacement set of chain plates could be made using just a hacksaw, grinder and drill press at moderate cost I'd be inclined to replace both the chain plates and bolts.

Cognitive dissonance?

Fatigue damage is cumulative and if the crack in one chain plate is caused by fatigue it is quiet probable that similar fittings placed under similar loads will also fail. The consequences being the possible loss of the mast, and possibly even the vessel under certain circumstances, it would be prudent to replace all the suspect components.

[thomm225]

Originally Posted by RaymondR

Cognitive dissonance?

Fatigue damage is cumulative and if the crack in one chain plate is caused by fatigue it is quiet probable that similar fittings placed under similar loads will also fail. The consequences being the possible loss of the mast, and possibly even the vessel under certain circumstances, it would be prudent to replace all the suspect components.

Pulled second chain plate today (port upper) and found second hairline crack.

So we are ordering 7' of SS Bar 3/16" thick, and I'll replace all the shroud chain plates and all nuts and bolts etc.

They are all nearly 50 years old.

The guy doing the work just bought his second Alberg 30 today! (he sold his other one a few years ago)

I'll check the forestay chain plate and backstay chain plate in the yard next Fall. They are thicker also so should be okay one more season

[stormalong]

Crevasse corrosion is commonplace in stainless steel. That hairline crack is the classic sign. Put that chainplate in a vice and try to bend it at the crack. Very likely that it will bend much easier than you expect and the rust is all the way through the plate. After 50 years and thousands of cyclic loads it is time to replace it all.

[markxengineerin]

That hairline crack is in a really unexpected location- not a highly stressed point at all when tension is applied on that pin hole. It just shows the sensitivity of the material to crevice corrosion. Definitely replace as much as you can afford to while all this is apart, the materials cost is negligible compared to the work you have already done.

[thomm225]

All the chain plates are coming out.

Mast is up with rigging cables missing chain plates tied to the next chain plate turnbuckle.

Also, I have the jib halyard tied to the forward lower turnbuckle on the side the upper chain plate is removed from.

Winds to 25 Sunday Night. Should be fine though

[rodsuter]

Hi - would suggest a conservative approach is warranted with these items of equipment. Thought I would share my experience, which Vyv Cox has documented nicely in : Westerly Oceanmaster 48 chainplates – Cox Engineering. When everything was opened up and replaced, it was just as serious as expected. Good luck.