Kittrina - dismasted.

[Zing]

View attachment 156886

Yuk! Do you know is it original from build in 1991? Looks like it might be crevice corrosion mixed with stress corrosion in a chain plate built into the deck?

 

[Rum_Pirate]

Colligo Marine could be your friend....

Where is it? Link?

 

[zoidberg]

View attachment 156890

Where is it? Link?

(Sigh....)

Colligo Marine - Synthetic rigging specialists


You'll find they have considerable expertise in re-rigging multihulls, and sorting out solutions. Tell John Franta I sent you.....

 

[Rum_Pirate]

(Sigh....)

Colligo Marine - Synthetic rigging specialists


You'll find they have considerable expertise in re-rigging multihulls, and sorting out solutions. Tell John Franta I sent you.....

Thanks.
I realize I should have googled.

 

[zoidberg]

Never mind. I need the practice....

 

[geem]

My sympathies.

Yep, boat stainless like 316 is a crap material. Shiny bling. A good material will never fail. It’s mad, we know it fails, but we repeatedly use the stuff.

I have said this before but 316 ain't what it used to be. Our original 316 s/s is far superior to the new crappy Chinese s/s that is sold as 316.
The old stuff doesn't corrode.

 

[Wansworth]

That’s quite a eye opener for thousands of boats with S/S fittings

 

[fredrussell]

I have said this before but 316 ain't what it used to be. Our original 316 s/s is far superior to the new crappy Chinese s/s that is sold as 316.
The old stuff doesn't corrode.

I was thinking along these lines a week or so ago. My standing rigging needs doing - nowt wrong with it but it’s 15 years old - but how does one know they’re buying as good a grade of rigging as the outgoing stuff?

My friend had his standing rigging replaced a year ago and there’s rust on it now. Not huge amounts, but there was absolutely no rust on the previous standing rigging after 15 years of use.

 

[sarabande]

Ooops, Rum, sorry to hear. Well done on saving the crew and the boat. That will keep you out of trouble for a week or two. And you can always use the old mast as a flagpole and CCTV in front of your pool.

Best of luck. Keep posting pics.

 

[Rum_Pirate]

I have said this before but 316 ain't what it used to be. Our original 316 s/s is far superior to the new crappy Chinese s/s that is sold as 316.
The old stuff doesn't corrode.

The Corsair F-27 I have was built in 1991.

Don't now which quality and source for stainless steel was used.

Doubt that any fittings into deck were replaced in the last 30 years.

 

[geem]

The Corsair F-27 I have was built in 1991.

Don't now which quality and source for stainless steel was used.

Doubt that any fittings into deck were replaced in the last 30 years.

My chainolates are original but 12mm thick 316s/s bar with no external signs off rust. We have checked the inside and all rust free.
We changed the aluminium toerail a couple of years ago and reused the 1980 M8 s/s bolts to bolt the new toerail back in. All bolts rust free and removed from the aluminium torail painlessly. The old toerail has 200 bolts each side. The new one went back with 150 bolts each side. The quality of the old stuff is a different world
Edit: corrected chainplate dimensions. 12mm not 10mm thick

 

[Rum_Pirate]

That’s quite a eye opener for thousands of boats with S/S fittings

Wonder why insurers don't ask for samples of various fittings to be removed and checked every ten or so years.

A surveyors visual inspection would not find it (cavity corrosion).

One 1/2"stainless steel nut I tried to move on a structural fitting below deck sheared off at first movement (same day another story. But it looked OK.

The ones in the pic below are from other side of the hull.

These are the bolts

 

[Rum_Pirate]

Stainless steel.

The operative word is 'stain less' not 'rust free'.

 

[Rum_Pirate]

My chainolates are original but 12mm thick 316s/s bar with no external signs off rust. We have checked the inside and all rust free.
We changed the aluminium toerail a couple of years ago and reused the 1980 M8 s/s bolts to bolt the new toerail back in. All bolts rust free and removed from the aluminium torail painlessly. The old toerail has 200 bolts each side. The new one went back with 150 bolts each side. The quality of the old stuff is a different world
Edit: corrected chainplate dimensions. 12mm not 10mm thick

the tang in question

 

[geem]

the tang in question

View attachment 156980 View attachment 156981

Wow! That's been knackered for sometime.

 

[srm]

Yes it does exist. The better grades of stainless won’t fail. Ditto of titanium and bronze and many other alloys.

The Waverider buoy I mentioned earlier was in the 1970's. According to the instrument manufacturer the hull and all other metal fittings in the mooring line were made of high grade marine stainless steel. (I forget the detailed spec). They are still in business so must have known what they were doing.

 

[billskip]

And you can always use the old mast as a flagpole and CCTV in front of your pool.

Web cam would be better

 

[Zing]

I have said this before but 316 ain't what it used to be. Our original 316 s/s is far superior to the new crappy Chinese s/s that is sold as 316.
The old stuff doesn't corrode.

I agree, new Chinese 316 is not as good as old European sourced stuff. That’s a different issue altogether though. My comment was that there are better alloys that are far superior, cost little more, it at all and should be used instead of 316. Actually, even better still to use composite materials, which modern builders are increasingly using for chain plates in particular.

I disagree that old 316 does not corrode. It does in the right environment or circumstance and catastrophically so.

 

[geem]

I agree, new Chinese 316 is not as good as old European sourced stuff. That’s a different issue altogether though. My comment was that there are better alloys that are far superior, cost little more, it at all and should be used instead of 316. Actually, even better still to use composite materials, which modern builders are increasingly using for chain plates in particular.

I disagree that old 316 does not corrode. It does in the right environment or circumstance and catastrophically so.

I am sure you are right but at 42 years old our 316 is fine. It's also heavily built which helps with longevity

 

[Tranona]

I am sure you are right but at 42 years old our 316 is fine. It's also heavily built which helps with longevity

Same with my even older Golden Hind. However unlike many designs (such as the tri in this thread) all the chain plates are external bolted through the topsides with stainless backing plates inside rather than passing through the deck. A disaster waiting to happen unless the seal through the deck is perfect and the attachment below is not hidden or embedded in a knee or a bulkhead. Many 1970-1990s designed boats fail in this respect - and the chain plates fail through a combination of crevice corrosion and stress, just as in the photo in post#34.

Probably little to do with the quality of the material - even the best 316 is susceptible to crevice corrosion.

Design of shroud attachment has come a long way since then with first through deck tiebars down to the keel through such things as internal structural bulkheads or dedicated webs to the keel load bearing structure or more recently back to external chainplates bolted through to laminated internal structures and even composite laminated into the hull structure.