# Embedded Chain plate maint/replacement



## chucklesR

I promised in this thread to start a new thread on the steps going forward.
http://www.sailnet.com/forums/gear-maintenance/104260-chain-plate-impact.html
This is my attempt at doing so.

Last night I pulled the joinery off and took a look at what I'd be needing to do to replace the chain plates.
Just a reminder - 1987 Irwin 38 CC MkII, chain plates embedded in the fiberglass, the tab with the pin hole (for the shroud) goes through a 2 inch thick toe/cap rail.
Here's the overall view:


The issue that spring boarded this:


That area from the outside on a FLIR image

That area from the inside on a FLIR

That area eyeball view, obvious long term water leak (previous owner).


Okay, here's the big one. That area - no wood or joinery over it. Raw hull.


What you are seeing is two of the three chain plates (the forward one is on the other side of the bulkhead). The chain plates have two horizontal 'tabs' - like an inverted orthodox cross. I do not know how they are joined, no bolts are obvious so I assume a weld.
The obvious dirt is from long standing wet/rot over the years. I had no leaks at all until I removed the jelly fish/snot over the chain plate covers while doing the teak rails. It is all obviously years old. 
Between the two horizontal tabs of the plates are some obviously well caulked screw pointy ends - they are what is holding the 2 inch thick, 3 inch wide rub rail on.

There is a heavy glass strip at the bottom of the plates, this folds horizontal over where the coring obviously starts (as well as the gel coat). 
At the top there is a gel coat cover strip, up under that looks like this.


Those screws are bunged toe rail/cap rail, stanchion bases etc, going through the bases, teak, and folded 'shoebox' lips of the deck/hull.

Here's the underside showing a plate -









That's enough for now.


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## Faster

This is going to be some job.. I expect you'll need to get to the opposite side as well at some point?

Once you get the glass off the inside I suppose you're hoping to pull the chainplates out from inside? or are you going to have to cut them out?

I expect you'll find the external crazing is from corrosion swelling on the plates.


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## davidpm

I'm confused, how are the chain plates fastened? 
They can't just be glassed to the hull and that is all, can it?

Is their any chance that they keep going down and attach to something below the seat. I can't tell from the picture if they stop or keep going.

I notice that they are in the middle of a span not at a bulkhead.
That means that the compression force has to be handled by the deck, yes?

Is that a nut at the bottom end of the forward chain plate?

Nice pictures, thanks for that!!!


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## deltaten

Oh, Man! Looks like a nasty bit of work ahead!? Appears to be a glassed -in arrangement to me.
Best of luck to ya


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## StormBay

I see two, how is access to the forward most plates (forward lowers I'm assuming)



davidpm said:


> I'm confused, how are the chain plates fastened?
> They can't just be glassed to the hull and that is all, can it?


These Irwin's have chainplates that are yes, simply glassed in. Its not that uncommon. Their are quite a few different boat builders that fastened chainplates this way on at least some of there models. Allied Luders 33, Hans Christian 33, Endurance 35 are just a few that come to mind.


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## Maine Sail

chucklesR said:


> There is a heavy glass strip at the bottom of the plates, this folds horizontal over where the coring obviously starts (as well as the gel coat).
> At the top there is a gel coat cover strip, up under that looks like this.
> 
> 
> Those screws are bunged toe rail/cap rail, stanchion bases etc, going through the bases, teak, and folded 'shoebox' lips of the deck/hull.


Chuck,

While you're in there you may want to add some through bolts to the hull/deck joint as opposed to just screw & glue....


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## Ajax_MD

StormBay said:


> I see two, how is access to the forward most plates (forward lowers I'm assuming)
> 
> These Irwin's have chainplates that are yes, simply glassed in. Its not that uncommon. Their are quite a few different boat builders that fastened chainplates this way on at least some of there models. Allied Luders 33, Hans Christian 33, Endurance 35 are just a few that come to mind.


For the life of me, I cannot understand why a person would replicate this method instead of simply bolting them to the hull with suitable reinforcement.


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## chucklesR

David,

The nut at the bottom of the forward (actually the center) plate is used to fasten a ground wire, it goes from there to the keel. 

The plates stop at the heavy glass strip, they do not go anywhere else. 

I'm not an engineer, I don't know where the compression is going - I thought it was to the keel, the mast is deck stepped with a post directly under the mast that transfers the compression to at 3/4 plate 2 inches above the (encapsulated) keel. 


Maine Sail, you betcha - some of those screws have got to be replaced by bolts, probably all of them that are for stanchions and jib tracks - if I can get to the bottoms. 


I have to get tarps, plastic, vacuums, tyvek suits and all that. Then it's off to fiberglass dust hades for a couple weeks. 

I'll shoot some pics on the way.


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## overbored

not sure what you worried about where the compression is going. the mast is in compression to the keel. the chainplates are in tension. fiberglass is very strong in tension. get a Fein saw for cutting away the glass. very little dust and the best tool for fiberglass work. worth the money.
FEIN Multimaster Oscillating Multi-Tool Kit-FMM 250 Start Q at The Home Depot


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## davidpm

overbored said:


> not sure what you worried about where the compression is going. the mast is in compression to the keel. the chainplates are in tension. fiberglass is very strong in tension. get a Fein saw for cutting away the glass. very little dust and the best tool for fiberglass work. worth the money.
> FEIN Multimaster Oscillating Multi-Tool Kit-FMM 250 Start Q at The Home Depot


It is obviously OK as it has lasted a long time on a lot of different boats. I'm just trying to understand the loads.
The mast is pushing down that makes sense.
The chain-plates are pulling up.
Some portion of the load however is attempting to make the boat narrower.
I see a lot of boats that have the chain plates connected to a bulkhead. 
The bulkhead is tabbed into the hull distributing the load.
The bulkhead often has a small beam that goes across the whole boat again distributing the load.

In this case the load attempting to make the boat narrower has to be taken by the deck.

I'm not saying it is a problem unless of course you had a soft deck.

I guess I find it hard to believe that a bandage of glass over the chain-plate on the hull is all their is to it. 
Is it possible they are relying in part on 5200?
Does polyester resin stick that well to SS?

Did they do some tricks like put some holes in the stainless so the resin would form keys?

What I'm saying is that a SS bar bolted to a bulkhead makes sense to me. It is obviously strong.

This kind of construction has stood the test of time so must be pretty good, I'm just trying to understand it.


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## Faster

overbored said:


> not sure what you worried about where the compression is going. the mast is in compression to the keel. the chainplates are in tension. fiberglass is very strong in tension. get a Fein saw for cutting away the glass. very little dust and the best tool for fiberglass work. worth the money.
> FEIN Multimaster Oscillating Multi-Tool Kit-FMM 250 Start Q at The Home Depot


Second the Fein for cutting over a zip-cut/angle grinder.


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## SVTatia

StormBay said:


> ...Allied Luders 33, Hans Christian 33, Endurance 35 are just a few that come to mind.


Allied bolted the Luders 33 chain plates to wooden "knees" glassed to the hull and then glassed-over the entire thing.



Faster said:


> Second the Fein for cutting over a zip-cut/angle grinder.





Faster said:


> Second the Fein for cutting over a zip-cut/angle grinder.


I would also suggest a multi-tool, not necessarily Fein. I would recommend a Milwaukee which is cordless and comes with two batteries which I was amazed how they last - for a much lesser price (tool and blades). The important piece is the kind of blade, and I would suggest you get 2 or 3 of the half-circle shaped ones with many small teeth - they have worked very well for me to cut thru glass - use a back and forth motion with them. Have a vacuum going at the same time with the nozzle close to the tool and you'll remove the glass cleanly in no time at all.


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## StormBay

davidpm said:


> I guess I find it hard to believe that a bandage of glass over the chain-plate on the hull is all their is to it.
> Is it possible they are relying in part on 5200?
> Does polyester resin stick that well to SS?
> 
> Did they do some tricks like put some holes in the stainless so the resin would form keys?


The chain plates in this one look like they have bars or rods welded to them, to form the upside down T shape that you see, which is than glassed into the hull. If the plates don't break they would have to rip out all of that glass before they pulled out the T shape bars and therefor don't have to rely on the bond between the fiberglass and the stainless. As SVTatia pointed out the Luders 33 use a different method of doing essentially the same thing (i.e. not relying on the bond between fiberglass and metal but rather fiberglass to fiberglass. Make sense?


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## miatapaul

SVTatia said:


> I would also suggest a multi-tool, not necessarily Fein. I would recommend a Milwaukee which is cordless and comes with two batteries which I was amazed how they last - for a much lesser price (tool and blades). The important piece is the kind of blade, and I would suggest you get 2 or 3 of the half-circle shaped ones with many small teeth - they have worked very well for me to cut thru glass - use a back and forth motion with them. Have a vacuum going at the same time with the nozzle close to the tool and you'll remove the glass cleanly in no time at all.


Yes the cheap tools work fine, but the cheap blades don't last at all. A couple of uses in soft wood and the "Workmate" (Loews house brand) brand blade was shot. Though the $35 Workmate brand tool works quite well. I have borrowed a Fein, and it seemed to operate a bit smoother, but did not work any better on my projects. And with all the fiberglass dust, that may just do in the tool anyway. The Harbor Freight multi tools seem to have it's fans as well.


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## mitiempo

davidpm said:


> It is obviously OK as it has lasted a long time on a lot of different boats. I'm just trying to understand the loads.
> The mast is pushing down that makes sense.
> The chain-plates are pulling up.
> Some portion of the load however is attempting to make the boat narrower.
> I see a lot of boats that have the chain plates connected to a bulkhead.
> The bulkhead is tabbed into the hull distributing the load.
> The bulkhead often has a small beam that goes across the whole boat again distributing the load.
> 
> In this case the load attempting to make the boat narrower has to be taken by the deck.
> 
> I'm not saying it is a problem unless of course you had a soft deck.
> 
> I guess I find it hard to believe that a bandage of glass over the chain-plate on the hull is all their is to it.
> Is it possible they are relying in part on 5200?
> Does polyester resin stick that well to SS?
> 
> Did they do some tricks like put some holes in the stainless so the resin would form keys?
> 
> What I'm saying is that a SS bar bolted to a bulkhead makes sense to me. It is obviously strong.
> 
> This kind of construction has stood the test of time so must be pretty good, I'm just trying to understand it.


It is a very strong way to attach chainplates if done properly. With a well built hull and deck there are no issues. It is not a bandaid of glass holding them in - the force is straight up pretty much for the uppers and inward slightly for the lowers. The chainplate's force is basically upwards and the overlap of the hull and deck (hopefully not just screwed together) places a good thickness of glass stopping upward movement. The Spencer 35 uses basically the same method except it is a bar that runs fore and aft and not as far down the hull and it has stood the test of time as well as long voyages by Hal Roth, Paul Lim and others.

But with modern knowledge of crevice corrosion it is a lousy way to attach the plates leaving any corrosion hidden from view. With chainplates being hard to seal over time moisture will eventually get in and corrosion will follow.


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## davidpm

So the next question is how to put it back together again so they can be inspected easily and/or replaced?

Bolting right through the hull is the obvious solution.
External is another obvious solution.

I doubt if most owners would be willing to change the look of the boat that much.
It really looks pretty and is out of the way coming out of the cap rail like it does.

Of course the argument could be made that they lasted over 30 years so put back together with epoxy instead of polyester and call it good for another 30 years.

If a better mounting is impossible maybe this is the right place for titanium regardless the cost.


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## SloopJonB

davidpm said:


> This kind of construction has stood the test of time so must be pretty good, I'm just trying to understand it.


Actually it hasn't. It stands the test of about 25 or so years and then presents a HUGE nasty problem to the owner at that time - keep following the thread to see how nasty. The worst part of it is that it precludes inspecting the chains for crevice corrosion.

It is a quick & cheap way to install chains, no other reason for it.


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## mitiempo

Simplest solution is on the outside of the hull. Without a bulkhead in each plate's location there are no other options I can see except the original method. That was probably the reason it was done this way to start with - without knees which would have been in the way of interior cabinetry or bulkheads at the right place it allows placement anywhere the builder wanted.


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## mitiempo

davidpm said:


> If a better mounting is impossible maybe this is the right place for titanium regardless the cost.


Wonder how bronze would survive installed this way for a few decades. Problem is that water will get in eventually.


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## davidpm

Once you cut out the chain plates I would be interested in how thick that bandage of glass is covering them?


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## davidpm

SloopJonB said:


> It is a quick & cheap way to install chains, no other reason for it.


Some of the boats that use this method are not known for cheap.
There are other reasons too.
It allows for clear side decks and flexibility in cabinetry.

Granted there are other ways to get those advantages.
So never mind it was cheap.

Even on this boat it might be possible to install knees but the cabinets would have to be rebuilt. Very big job.


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## davidpm

So if you look a a boat and see the chainplates topside and there is no way to see any attachment below is their any other way they could have been built that doesn't use a knee or bulkhead or exterior bolts through the hull and is NOT glassed in?

IOW is their any construction method where the chainplates are flush or nearly flush with the hull interior and still allows inspection.


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## miatapaul

davidpm said:


> Some of the boats that use this method are not known for cheap.
> There are other reasons too.
> It allows for clear side decks and flexibility in cabinetry.
> 
> Granted there are other ways to get those advantages.
> So never mind it was cheap.
> 
> Even on this boat it might be possible to install knees but the cabinets would have to be rebuilt. Very big job.


Yes, this is how Island Packet does it, and is one of the ways they cut quality and save cost, but do not pass it on to the buyer.


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## AllThumbs

I ground out my chainplates and re-glassed them in, after shortening them a little. I cut off the high stress area where it goes through the deck.

The crazing on your hull looks like water got in the chainplate pocket and froze, many years in a row. I have heard some folks drill a small hole in the pocket on the inside to allow water to drain out. The builder just glassed over the chainplate so there is plenty of room for water where the glass makes a radius over the edges of the steel chainplates. No way to know how it is in there unless you cut it out and inspect. It's perfect conditions for crevice corrosion.


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## AllThumbs

Last few pictures


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## chucklesR

FWIW I spent a lot of time discussing the plates and how to fix or re=-install with both Maine Sail and Jeff_H, neither of which is a lightweight when it comes to stuff like this. 

Neither of them had knowledge of the shape of the plates prior to today - all I could tell them was that a horizontal band/tab was involved, but no through bolts etc.

Titanium is one of the the things I'm looking at, the could be thinner in all dimensions. 
Science has moved on since 1987, I have a LOT more options than "drill through the existing and bolt new ones on the outside" - that's the first and last option according to the Irwin 'expert' - a Mr. Gene Gammon. 
I prefer taking advice from someone that does not tell me to leave the possibly rusting old ones in place as backing plates. 

I'm still thinking- I might go with a hybrid inner/outer.
I have to rebuild the 'furniture', i.e. book shelves, I do not have to rebuild them they way they were.


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## jimgo

Chuck, I hope this progresses faster and more easily than you expected. If you wind up needing a hand, give me a shout.


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## SloopJonB

mitiempo said:


> Simplest solution is on the outside of the hull. Without a bulkhead in each plate's location there are no other options I can see except the original method. That was probably the reason it was done this way to start with - without knees which would have been in the way of interior cabinetry or bulkheads at the right place it allows placement anywhere the builder wanted.


I would say the simplest solution would be to put them back where they were on the inside of the hull but bolt them through the hull rather than glassing them in place.

On that boat putting them on the outside would present big problems because of the heavy cap rail and rub rail.


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## davidpm

I'm envisioning a way to make new chain plates that will be removable for inspection but be similar to the existing ones.

Let me see if I can explain in words what should be a drawing.

Glass with epoxy two or three horizontal stainless plates about the same way the current T crosses are glassed in.
The difference is that they are glassed in such a way so their is a slot left in the middle wide enough so the vertical chain plate can be slipped up under each horizontal strap and out through the slot in the cap rail.
Now just use flat head machine screws through the horizontal straps and tapped into the vertical chain plates.

The bottom of the chain plate can have a doubler piece welded on as a stop against the bottom horizontal piece.

The whole thing can have an inspection cover over it so it can be inspected.
The horizontal pieces glassed in should never get wet and last indefinitely.
The vertical piece can just be unscrewed and withdrawn and the critical part just below the cap rail inspected.

In any event even if water did get in it would not be trapped in a pocket.

Any concern about the strength of the machine screws can be engineered away by simply changing the size of the vertical member. It can be wider or thicker under the cap rail if you need more screw area and the existing width above the cap.

This would be a modest increase in cost mostly labor to deal with drilling and tapping a couple dozen screws rather than welding.

Do you think this would work?


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## copacabana

SloopJonB said:


> I would say the simplest solution would be to put them back where they were on the inside of the hull but bolt them through the hull rather than glassing them in place.
> 
> On that boat putting them on the outside would present big problems because of the heavy cap rail and rub rail.


I've seen a few boats where the external chain plates curve around the cap rail and rub rail. I don't believe this is ideal. I wonder if you couldn't just cut a slot in the cap and rub rails so the external chain plates would be flush with the hull and pass through the slot. You could leave a little extra space, a few mm, in the slot so water would run down and out of the slot, on the outside of the hull. With some SS backing plates you'd have a pretty bulletproof system you could inspect visually and service easily.


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## arf145

davidpm's solution sounds awfully good. It _sounds _like it puts the stresses pretty much where they were before, without embedding parts that get wet above deck and without messing with the outside of the hull or taking up huge amounts of interior.


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## mitiempo

David's idea is interesting but would not be as strong as the original. Instead of the large chainplate glassed in solidly the vertical plate's strength would only be as good as the bolts used. If you are going to put 4 or 5 large bolts through the hull to make it strong enough you may as well install the plate outside for easier inspection. This will also eliminate the hole through the deck that exists currently.


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## arf145

With David's idea, I don't believe the bolts were going through the hull, just through the chainplate into the cross plates. Doesn't it pretty much always come down to the bolts? I guess it did with my last boat, a Pearson 28-2, where I believe the chainplates were fastened to a knee in the hull with 3 (I think) bolts.


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## Ajax_MD

chucklesR said:


> FWIW I spent a lot of time discussing the plates and how to fix or re=-install with both Maine Sail and Jeff_H, neither of which is a lightweight when it comes to stuff like this.
> 
> Neither of them had knowledge of the shape of the plates prior to today - all I could tell them was that a horizontal band/tab was involved, but no through bolts etc.
> 
> Titanium is one of the the things I'm looking at, the could be thinner in all dimensions.
> Science has moved on since 1987, I have a LOT more options than "drill through the existing and bolt new ones on the outside" - that's the first and last option according to the Irwin 'expert' - a Mr. Gene Gammon.
> I prefer taking advice from someone that does not tell me to leave the possibly rusting old ones in place as backing plates.
> 
> I'm still thinking- I might go with a hybrid inner/outer.
> I have to rebuild the 'furniture', i.e. book shelves, I do not have to rebuild them they way they were.


If you're going to replicate the original method, then titanium seems a good way to go.

AllThumbs had a good idea, about leaving weep holes. Not only would it prevent freeze damage, but it would also provide an indicator of trouble when you start seeing water stains.

People are also right when they point out that this system lasted 25 or 30 years. If you do it right, you'll probably never worry about it again in your lifetime.

I guess I kind of overreacted when I said to just bolt them to the hull.


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## Rezz

Subscribing. This'll be interesting.

What about going ahead and drilling a couple small holes in the bottom of the glassed in area now just to see what happens?


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## chucklesR

Let's see if I can describe this well - I don't have a good drawing tool that is easy to use.

1) make some knees out of g-10 - laminate to a 1 inch thickness. Put them in - one per plate with epoxy, fillets and heavy glass (maybe CF, double layer). Smooth, fair, paint.
2) turn the plates 90 degrees, bolt through the knees, backed on the other side. 
3) build joinery back where and how I like. 

I'd have inspectable plates, be able to see any leaks and rectify and I 'think' just as strong. The knees would run from the deck to the core area, really don't need to be much more than the width of the plate as it's more about spreading the load - and that's on the fillets and fiber glass tabs and tapes. 

BTW - let's call the discussion on 'it's on the bolts' pretty much done. The bolts can pretty much hold the entire weight separately - look up the tensile and sheer strengths. 
The shrouds are rated about 9k SWL - bolts pretty much better than that.


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## davidpm

mitiempo said:


> David's idea is interesting but would not be as strong as the original. Instead of the large chainplate glassed in solidly the vertical plate's strength would only be as good as the bolts used. If you are going to put 4 or 5 large bolts through the hull to make it strong enough you may as well install the plate outside for easier inspection. This will also eliminate the hole through the deck that exists currently.


At the risk of starting something I'm not prepared to finish.

This is a little like the difference between some anchors. Some are welded some are bolted. As long as the numbers work out from a strength point of view it probably don't matter.

All you have to do is make sure the bolts are about 10 times stronger than the piece of wire connected to the plate and I suspect it doesn't matter any more.

My idea was that the bolts thread into the vertical plate and do not go through the hull.

The width and thickness of the plate below the cap rail, it can be doubled for more thickness and/or wider for more room to space bolts, can be adjusted until the strength and the number of bolts is as strong as needed.


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## davidpm

chucklesR said:


> 1) make some knees out of g-10 - laminate to a 1 inch thickness. Put them in - one per plate with epoxy, fillets and heavy glass (maybe CF, double layer). Smooth, fair, paint.
> 2) turn the plates 90 degrees, bolt through the knees, backed on the other side.
> 3) build joinery back where and how I like.
> 
> BTW - let's call the discussion on 'it's on the bolts' pretty much done. The bolts can pretty much hold the entire weight separately - look up the tensile and sheer strengths.
> The shrouds are rated about 9k SWL - bolts pretty much better than that.


That would work strength wise but I was trying to save the guy the significant hassle of redoing the joinery.


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## asdf38

Faster said:


> Second the Fein for cutting over a zip-cut/angle grinder.


All of them!

I'll also plug for Milwaukee. The M12 line has a lot of tools which have been indispensable for me on the boat - Multi-Tool (which also sands), Rotary Tool (Dremel) and compact right-angle drill in particular.

They all share batteries so when I'm upside down somewhere and one battery dies I can swap it with whatever is in the tool nearby. And I have have several tools on hand without several power cords.


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## SVTatia

chucklesR said:


> ...
> 1) make some knees out of g-10 - laminate to a 1 inch thickness. Put them in - one per plate with epoxy, fillets and heavy glass (maybe CF, double layer). Smooth, fair, paint.
> *2) turn the plates 90 degrees, bolt through the knees, backed on the other side.*
> 3) build joinery back where and how I like.
> 
> ...


That should work. When you laminate the knees, spread the fb widely to distribute the load. The trick will be to make the "twist" on the plate itself (weld?), as it needs to be facing athwartships at the deck level and fore and aft below deck to be bolted to the knee. And it will need to be inserted into place from below.
You then build the cabinetry around it with an inspection port.


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## chucklesR

davidpm said:


> That would work strength wise but I was trying to save the guy the significant hassle of redoing the joinery.


Um, I'm the guy - and the joinery is already 'gone' even though I took it out in one piece I will not be reusing it.


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## chucklesR

SVTatia said:


> That should work. When you laminate the knees, spread the fb widely to distribute the load. The trick will be to make the "twist" on the plate itself (weld?), as it needs to be facing athwartships at the deck level and fore and aft below deck to be bolted to the knee. And it will need to be inserted into place from below.
> You then build the cabinetry around it with an inspection port.


I've got almost 2 inches of opening between the hull and the cap rail (inside the bulwark). I think I can just re-cut an awarthship slot in the toe rail. If not
I've got a machine shop that I think can do the twist hot and re-anneal it.

The 'hump' below is the encapsulated plate - all of that would be cut down/ground flush to hull - lots of room for a plate at 90 degrees to hull.


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## Alex W

I don't understand why the twist is necessary. The chainplates on my Pearson 28-2 with knees have no twist, the knees are U-shaped with clearance to access the bolt heads. I haven't looked my friend's Yankee 30 (which also uses knees) too closely but I think it worked the same way.

I do think that knees are the way to go.


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## davidpm

chucklesR said:


> Um, I'm the guy - and the joinery is already 'gone' even though I took it out in one piece I will not be reusing it.


If you are going to redo the wood anyway then your options are wide open.

The knee idea would be great and you might even be able to make it so the chain plates are completely visible inside the cabinet just like in many other boats.

I really like the way you take pictures. They really show what is going on.

Good luck with your project.

I'm sure you have good reason to replace the interior woodwork as I know you are very experienced.

Just as a warning to others though the replacement of interior joinery so it looks good and matches is often a much bigger job that it would seem at first blush.
It is one thing to do structural repairs where mostly strength is important.
It is quite another thing to do interior joinery where, fit and matching existing finish and utility are all important.

I would think that replacing the joinery on this project would probably be at least as much work and probably more work than the structural part.

But I'm a few miles away so you know best.
I was a cabinet maker in a past life and all I know it it always seems to take me a lot longer than I figured it should to do cabinet work on a boat.

If you change the orientation of the chain plates from for to aft to side to side you will have some cap rail repairs to do that will show, yes?

As you can see I'm very concerned about creating ancillary finish projects during the process of repairing a structural problem. I've been burned before.

A very classic case of this when someone replaces an engine and they have to cut into cabinetry to fit the new engine.
I've seen several of those jobs that just never looked right and it severely reduced the value of the boat.


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## SloopJonB

I don't understand the comments about twisting the chains to mount them on a knee - a knee is just a mini-bulkhead so the chains will mount athwartships just like they would if mounted to a bulkhead. The slots in the deck would have to be filled & recut to change the orientation.

A really skookum setup would angle the knees for lower shrouds to put the chains in line with the angle the shrouds form with the mast - angled aft for the forward lowers and forward for the aft lowers.

I still say the simplest method would be to clean up the area where they currently sit to get a smooth mounting surface and bolt them through the hull - virtually a direct replacement for the existing setup and only a few S/S carriage bolt heads showing on the outside. Just as easy to remove for inspection as any other bolted setup too.


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## davidpm

SloopJonB said:


> I still say the simplest method would be to clean up the area where they currently sit to get a smooth mounting surface and bolt them through the hull - virtually a direct replacement for the existing setup and only a few S/S carriage bolt heads showing on the outside. Just as easy to remove for inspection as any other bolted setup too.


That certainly sounds simple and would look OK for some people but fiberglass is brittle especially gel coat. 
So exactly how much to you torque the bolts so the heads doesn't crack the gel coat. The obvious solution is to use a standard bolt with a washer. But now it doesn't look so good. Then the next option is a backing plate. The backing plate could come right up to under the cap and look ok for some folks but it is a different look for sure.

I'm pretty sure carriage bolts are best set into wood where it is expected that they will crush in a little as you tighten them.


----------



## chucklesR

Davidpm,

Not much I can't do with wood. I'm not a professional but I 'm a pretty fair amateur wood smith with both power and wood tools. I saved the old facing so I've got both ready at hand trim and bits for stain matching.

JonB - the 'twist' is because the plates are flush to the hull. Knees would by definition be perpendicular to the hull (at right angles). As I said in my response I'd probably just change the cap rail by re cutting a slot awarthship. 
I'd repair the current slot with a dutchman, then cut the new.

Close up of the cap rail, just for entertainment purposes.

Before:









You can tell it's really 5 strips of teak. Anywhere it's joined it has a nice curved joint like it should be. This is with 1 coat of JD's Total Care, natural teak - no gloss / clear yet.


----------



## Alex W

Knees don't need to be built in a way that requires a twist. This photo isn't mine (and isn't a Pearson 28-2), but closely resembles how they are done on my boat:









The knees don't need to be that deep if space is a concern. They only need to come in far enough for you to get a wrench around the back side of them.

Edit: one thing that isn't clear from this photo is how you access the back of the chainplate. On my Pearson there are cutouts in the knees to access the nuts on the backside. I'll take photos when I'm next at my boat (likely this afternoon).


----------



## AllThumbs

I think through bolting would work. I doubt you could pull a carriage bolt head through the glass, and I expect you would use 2 or 3 on each chainplate. Also remember the stress is in shear, making it even more difficult to pull a carriage head through the hull.

Also, don't forget, at the mast the rig is usually fastened to a tang that is held on by 4 pop rivets. We get all anal about how the chainplates are fastened (and we should be) but it only needs to be stronger than the tang at the top.

No one has suggested just glassing in new plates. That's how it's been for 30 years, so no reason to think it's not adequate. Grind out the old ones, smooth everything with 30 grit on an angle grinder, and glass in new ones. On mine, I first filleted in the chainplate with thickened structural epoxy (after pushing the chainplate into a bed of same), then added 5 layers of 9 oz. cloth over them.

For sure you need to grind one out to have a look at what's going on. Can't really make any decisions until one is out.


----------



## SVTatia

SloopJonB said:


> I don't understand the comments about twisting the chains to mount them on a knee - a knee is just a mini-bulkhead so the chains will mount athwartships just like they would if mounted to a bulkhead. The slots in the deck would have to be filled & recut to change the orientation.
> 
> A really skookum setup would angle the knees for lower shrouds to put the chains in line with the angle the shrouds form with the mast - angled aft for the forward lowers and forward for the aft lowers....


A knee is not just a mini-bulkhead - its is an essential structural point that needs to be strong enough to support the whole rig!
Angled knees? Much easier said than done. But you hit it on the head by mentioning that the chain plates need to be set at the same angle as the two lowers, but only if they are oriented fore and aft. As you see, the original ones mounted athwartships don't need to be, thus if the plates are bolted to the knees, they need a weld or hot-formed to be aligned with the lowers angle --- now: how do you measure the angle that they should be at?


----------



## xort

As mentioned previously, I would replace them the same way they were and get 30 more years.

you start reinventing the design and who knows what you might end up with. Are you getting a naval architect to approve the structural changes? If not, what will insur man have to say?

Do you know if the hull adjacent is cored or solid glass?


----------



## chucklesR

Xort,

Naval Architect? No, just a couple smucks I met at the Marriott during the boat show. We didn't even draw it up on a napkin or anything but I think I heard most of what they said over the ambient noise.

Here's a picture of the culprits - but the furry faced one with the most opinions was actually holding the camera:









I don't have a picture of the "later that night at Jeff_H's" because you kept drifting off to inspect the inside of your eyelids.

Honestly, if Maine Sail and Jeff_H say 'maybe' a couple times doesn't that equal a NA's considered judgement?


----------



## Maine Sail

Alex W said:


> Knees don't need to be built in a way that requires a twist. This photo isn't mine (and isn't a Pearson 28-2), but closely resembles how they are done on my boat:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> The knees don't need to be that deep if space is a concern. They only need to come in far enough for you to get a wrench around the back side of them.
> 
> Edit: one thing that isn't clear from this photo is how you access the back of the chainplate. On my Pearson there are cutouts in the knees to access the nuts on the backside. I'll take photos when I'm next at my boat (likely this afternoon).


On those knees there are 3/8" thick 316L SS drilled & tapped backing plates inside the knee. The knees are sealed from above with the deck flange so no water can get into them.


----------



## chucklesR

Got my choppers and grinders out.

For the gear heads, I'm using a Dremel 4000, a Chicago Electric pro multi tool, a Dewalt right angle grinder, hammers, pry bar (okay, screw driver) and what ever else I grab.

The dremel, with a carbide coated cut wheel slices the resin heavy FG like hot butter, scores the stainless plates and - with a flexible attachment - is probably the best and most accurate tool.

The CE multitool with both a straight and semi-round metal/wood cutting blade is almost as fast as the Dremel, much heavier and not as precise. It's a cleaner less dust producing cut.

The grinder is for cutting the stainless, faster than anything in FG too - but in about 5 seconds of oops can cut right through the hull if you are using a thin cutter. It will likely get the nod to do the heavy grinding and shaping.

I cut out 1/2 of one plate, starting with the multitool. That produced a little over 2 cups of water (fresh). Yep, it's all wet back there.
'back there' you ask?
The chain plate, both vertical and horizontal parts, never actually touch the hull. There is an air gap the entire length and width with the exception of a single previously unknown thin vertical bar at the very bottom. That bar is firmly and completely bonded to the hull. 
The rest - covered on three sides, and pristine on all the bits and pieces I've gotten out.

Here's the pic's - you can see the gap between the plate and the hull, and the buried horizontal bar (Just a bit in one pic). The bar in the 2 pics is the same one - both sides.

Sorry about the focus, cell phone camera and all that. 
The bottom 't' - aft lower:









Out of focus, but you can see the 'air gap'.









You can see I've cut away some to expose the 'new' bottom bar, I've also cut off the left side horizontal at this point.










What was the left horizontal cross bar - this is the side that was covered in fiberglass (the shine is from the dremel cutting it out).









Here's the flip side - factory finish. 








In case you are wondering...


----------



## miatapaul

Had no doubt you would do it right, look forward to seeing the progress!


----------



## SVTatia

Tool selection = excellent. I assume you already have the vacuum.
Also the tent was pretty smart. I also assume you look like a space creature in the Tyvek and breathing masks?

The bad stuff is starting to show, and as you grind you'll start planning the way you'll be putting it back together.

Best of luck and we'll be here waiting for the "dust to settle" and keeping up with progress.


----------



## endoit

Looks like a major undertaking. I am your neighbor from across the river in the Bristol 35.5. I have a Fein tool set with some of the cutting tips that maybe helpfull. If you need to borrow it you are welcome to it.


----------



## xort

chucklesR said:


> Xort,
> 
> Naval Architect? No, just a couple smucks I met at the Marriott during the boat show. We didn't even draw it up on a napkin or anything but I think I heard most of what they said over the ambient noise.
> 
> Here's a picture of the culprits - but the furry faced one with the most opinions was actually holding the camera:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> I don't have a picture of the "later that night at Jeff_H's" because you kept drifting off to inspect the inside of your eyelids.
> 
> Honestly, if Maine Sail and Jeff_H say 'maybe' a couple times doesn't that equal a NA's considered judgement?


My point is that it doesn't matter what you or I think of them, what will the insur co think of you making structural mods to the boat? Might not matter, but worth considering.


----------



## chucklesR

xort said:


> My point is that it doesn't matter what you or I think of them, what will the insur co think of you making structural mods to the boat? Might not matter, but worth considering.


The insurance company wouldn't know - because the surveyor wouldn't know.

Based on my previous experience with survey's I'd have to say that a change would simply not be noticed. 
I any case it's not likely as I am currently seriously doubting I'll find any problems at all - and therefore just replace as is.


----------



## chucklesR

endoit said:


> Looks like a major undertaking. I am your neighbor from across the river in the Bristol 35.5. I have a Fein tool set with some of the cutting tips that maybe helpfull. If you need to borrow it you are welcome to it.


Thanks Andy. I went out and got all new blades. I'm trying not to get paralyzed by the size of the job. While holding a big picture in my head I'm just taking it one step at a time. 
I'm getting hauled at Ferry Point 11/11, I suspect most of the work will be done there. I've been dinghy deprived all season (muskrats ate mine); swing over if you get a chance.

I noticed you didn't get out much this year - or at least I didn't see your boat gone much. Did you ever do the lesson's for the admiral?


----------



## endoit

I didnt get out more than a dozen times as I started new projects on the boat. The electric windlass is 90 % done with one anchor on 200 feet of chain and another on rope. Anchor locker was built, washdown pump installed and chain counter is yet to be mounted at the helm. Vacum flush toilet was installed. Now I need to address annoying leaks throughout the cabin and seal the mast, reseal 2 hatches, address the through hulls. No lessons yet.


----------



## chucklesR

Your done list is my 'do' list. I've got to get over there and eyeball it.


----------



## SloopJonB

chucklesR said:


> I've been dinghy deprived all season (muskrats ate mine)


 Sounds like a Frank Zappa album - "Muskrats Ate My Dinghy" - could have been the follow-up to "Weasels Ripped My Flesh".

OR, it could be a good name for a radical race boat - a sister to the Seattle boat "Aliens Ate My Buick"


----------



## Alex W

I took a few photos of my Pearson chainplate knees today:

Exposed and hidden part. Settee backrest normally covers the portion below the shelf:









Front of the knee:









Backside with backing plate:









I think the ones that I posted earlier from Maine Sail would be easier to retrofit.


----------



## chucklesR

Thanks Alex, 

That's all custom right?


----------



## Alex W

No, that is the stock configuration on my Pearson 28-2. I think the photo that I posted last week was from Maine Sail's CS36?


----------



## chucklesR

The only Pearson I've seen the guts on is a 365 - it's not near as neatly done.


----------



## Alex W

Yeah, I looked at a Pearson 32 before buying this one. On the Pearson 32 the chain plates weren't even inspectable!

I think most or all of the -2 Pearsons (28-2, 31-2, 33-2, etc) have chainplates installed this way. They were made in the mid to late 80s, just before the company went out of business.


----------



## Cruisingdad

chucklesR said:


> I promised in this thread to start a new thread on the steps going forward.
> http://www.sailnet.com/forums/gear-maintenance/104260-chain-plate-impact.html
> This is my attempt at doing so.
> 
> Last night I pulled the joinery off and took a look at what I'd be needing to do to replace the chain plates.
> Just a reminder - 1987 Irwin 38 CC MkII, chain plates embedded in the fiberglass, the tab with the pin hole (for the shroud) goes through a 2 inch thick toe/cap rail.
> Here's the overall view:
> 
> 
> The issue that spring boarded this:
> 
> 
> That area from the outside on a FLIR image
> 
> That area from the inside on a FLIR
> 
> That area eyeball view, obvious long term water leak (previous owner).
> 
> 
> Okay, here's the big one. That area - no wood or joinery over it. Raw hull.
> 
> 
> What you are seeing is two of the three chain plates (the forward one is on the other side of the bulkhead). The chain plates have two horizontal 'tabs' - like an inverted orthodox cross. I do not know how they are joined, no bolts are obvious so I assume a weld.
> The obvious dirt is from long standing wet/rot over the years. I had no leaks at all until I removed the jelly fish/snot over the chain plate covers while doing the teak rails. It is all obviously years old.
> Between the two horizontal tabs of the plates are some obviously well caulked screw pointy ends - they are what is holding the 2 inch thick, 3 inch wide rub rail on.
> 
> There is a heavy glass strip at the bottom of the plates, this folds horizontal over where the coring obviously starts (as well as the gel coat).
> At the top there is a gel coat cover strip, up under that looks like this.
> 
> 
> Those screws are bunged toe rail/cap rail, stanchion bases etc, going through the bases, teak, and folded 'shoebox' lips of the deck/hull.
> 
> Here's the underside showing a plate -
> 
> 
> 
> 
> 
> 
> 
> 
> 
> That's enough for now.


WOW!!!! I will follow this with interest. Good luck making this work.

Brian


----------



## chucklesR

Brian,

Been busy reading the OT?

Everyone else:

Notice the black bits under the heavy fiberglass tape section:









That marks both the beginning of the gelcoat, the beginning of the cored section- and I seriously think the beginning of the rot area- I'll be digging and such and keep ya'll informed.

My surveyor with the thermal camera (I do not yet have permission to name him) sent me photo's of the job his dad/partner is doing on a Irwin 43. They show clear and present danger (i.e. cracks) on the stainless bars that to date on mine have shown clean and no problems.


----------



## chucklesR

Just to let folks know what the reason for all the madness is.
Note the crack



Here's the good news. *That's not mine*. Its a plate from a Irwin 43 out of Norfolk Va that the surveyor who shot my thermal pics is currently working.

The left is the bottom - you can see the weld where the bottom horizontal bar would be - on my boat that would be directly under the heavy (yellowish) tape - the only part of the chainplate actually sealed in contact.


----------



## christian.hess

I am very interested in this thread...I have one embedded triangular chainplate on my port forward lower shroud that islander used to fix the stay to the hull...

it only shows corrosion on the triangular exposed plate and there is no rot in then fiberglass embedding material or the knee itself but it looks very weak in an engineering point of view and looks very thin...

I would like to know once you get to that stage how you rebed the knee and plate, and what exactly you will do to "protect" the embedded chaonplate if you go that route.

thanks and good luck

ps. Im doing a major refit on my islander 36, new bulkheads on all chainplates(even the cabinetry bulkheads) new 304ss plates, and retabbing and glassing the bulkheads

The new plates will also be extended, and my aft lowers that attach to the deck only will be reinforced with stringers and extra glass work.


----------



## SloopJonB

chucklesR said:


> Just to let folks know what the reason for all the madness is.
> Note the crack
> 
> 
> 
> Here's the good news. *That's not mine*. Its a plate from a Irwin 43 out of Norfolk Va that the surveyor who shot my thermal pics is currently working.
> 
> The left is the bottom - you can see the weld where the bottom horizontal bar would be - on my boat that would be directly under the heavy (yellowish) tape - the only part of the chainplate actually sealed in contact.


No wonder they buried it in glass - that thing is NASTY. They didn't even clean the spatter off it. If I was putting that in a boat I wouldn't want anyone to see it either.


----------



## chucklesR

christian.hess said:


> ps. Im doing a major refit on my islander 36, new bulkheads on all chainplates(even the cabinetry bulkheads) new 304ss plates, and retabbing and glassing the bulkheads


Just FYI - I would not go with 304 SS - go with 316 L - the L stands for low carbon. Less carbon = less rust, and yah, less strength (but still within design specs I bet).

Here's two more pictures found by Dylan (Dylan Bailey Yacht Services, the surveyor I used on this). 
*Again, not from my boat*:


----------



## overbored

The L does stand for low carbon but has nothing to do with rust. both 316 and 304 alloys of stainless steel come in an L variation. it is the extra chromium in the 316 that makes it more corrosion resistant than 304. the L does make the alloy less affected by chromium carbide precipitation after welding which can have an effect on intergranular corrosion of the welding heat effect zone


----------



## miatapaul

overbored said:


> The L does stand for low carbon but has nothing to do with rust. both 316 and 304 alloys of stainless steel come in an L variation. it is the extra chromium in the 316 that makes it more corrosion resistant than 304. the L does make the alloy less affected by chromium carbide precipitation after welding which can have an effect on intergranular corrosion of the welding heat effect zone


Is there any easy way to tell if they use the product you spec? How can you tell different grades of SS, unless you provide your shop with the product.


----------



## copacabana

When I remade a chainplate last year i asked the shop to keep the invoice and certificate from the steel supplier so I could see it was 316L. I'm not sure you would have a way of knowing without the invoice/certificate unless you took it to a lab.


----------



## chucklesR

overbored said:


> The L does stand for low carbon but has nothing to do with rust. both 316 and 304 alloys of stainless steel come in an L variation. it is the extra chromium in the 316 that makes it more corrosion resistant than 304. the L does make the alloy less affected by chromium carbide precipitation after welding which can have an effect on intergranular corrosion of the welding heat effect zone


Exactly - which for layman means - Less rust.


----------



## xort

Usually a magnet will have a very slight pull to 304 and zero pull to 316.


----------



## christian.hess

yeah thanks they did not have 316 at the time...the originals where specd to be 304 they have no noticeable pull tp them...so thats what we went with...they are highly polished anyways and I will be pulling them periodically...

the 316 failed cause fo crevice corrosion and cyclic loading...also where it was hidden, also 316 is slightlymore brittle and will crack suddenly whereas apparently 304 will stretch a bit more and give signs of failure something I see good on a chain plate that gets a lot of vibration if SAILED hard...


again Im eager to see what you end up doing...good luck!

ps. those pics are of the old chainplate? mine were really corroded and brown inside...not shiny at all like yours(the pic)


----------



## chucklesR

Now that I'm done coughing fiberglass out of my lungs and picking it out of my eyes here's the update. The Navy taught me to write in BLUF style - bottom line up front.

No corrosion found anywhere. If I had not cut the chainplate into pieces to remove it I would have no problem putting it back in and using it for another 30 years.

Lots of silliness certainly. No part of the chain plate actually touched the hull proper - just the three or four layers of glass and resin that where draped over it. 
In the photo's below you will see a short (3 inches per side) piece of round stock welded to the top. That was wrapped in glass and hidden right up against the overlap of the deck/hull - i.e. sneaky little last bit of 'what the heck is holding the damn thing in'.

All told - 6 hours to get the plate out - but a lot of that was expirimenting with different tools and methods. I bet I can get the next one out in 3 hours, if I bother.

Pics
all out - daylight coming in from above


Looking up - note the depth of the pocket the plate was in - and zero contact plate to hull. 


Cleaned up a bit, and my chopper chisel laid in for scale


The beast. Chopping it up in manageable pieces seemed the best way to get it out.
Note the round bastard bar at the top. 


Someday I will learn to focus a camera. There is no rust, no corrosion, no cracking.


----------



## chucklesR

This is where the bastard bar was 


I could fill the page with numerous pic's of close ups of the bar's on both sides. 
Frankly - no need. There is literally nothing to see. It's old, it's not polished (it was never meant to be seen), there is no sign of any deterioration what so ever.

I completed training as a metals processing specialist for the USAF in 1980. I can weld, forge,treat, bend and cut etc pretty much anything with the caveat that this was 30 years ago. That training including NDI (non-destructive inspection). 
This bar is fine for another 30 years, if it was in one piece.


----------



## StormBay

Was that the plate that was inline with the cracking on the outside of the hull from the original photos?


----------



## Ajax_MD

Fascinating stuff, Chuck.

So...now what?


----------



## chucklesR

Well, 

So now Jimmy from the rigging company visited today to work up an estimate for my standing rigging. 
We look at it and get to talking and planning and waving hands and such - I pull up my right angle grinder with a 1/8 cut off wheel and make a slice under the middle horizontal of the forward plate in the pictures (that's my upper shroud's chain plate). Roughly a half gallon of clear water comes out like it's under pressure. 

I'll be taking the rest out, grinding the area down flat and and replacing them with through bolted plates - all but the forward lowers which would require dismantling a head and a cedar closet. The forward lowers will get weep holes, but that's it. 

The conjecture at this point is the gel coat issues are because the plates were not properly attached throughout their span and length. I'm not sure I get that, but there it is.


Storm Bay - no that specific plate was the aft lower, it has a similar gel coat 'impact' looking spot below the rub rail but not in the blue area. My understanding from what Dylan is telling me is that the plates should all have been bedded in a foam like bedding compound that simply was not there. 
Any way, these 4 and the backing plate will be coming out, the hull/fiberglass sheath will be ground down, faired smooth and fit to the replacement plate, then bolted through with 5 bolts each.


----------



## AllThumbs

The gel coat issues are due to the freeze thaw cycle of all that water.


----------



## chucklesR

Doesn't explain why they appeared in July AT. 
Clearly not there in pics from April.


----------



## 44Kebeck

This thread has been of great interest to me as I own a 1988 Irwin 38 MkII. I have the same crazing in the gel coat around the chain plates. I have attributed this to trapped water and the freeze/thaw cycle. I drilled into the glass at the bottom of one plate and water drained out.

After seeing the condition of the removed plate replacing chain plates has moved a bit down my priority list but when I do start the project it will be external plates bolted through the old ones. My only question is the number and diameter of bolts I should use? The plates are 3/8" x 2" x 24".

44Q


----------



## jbogart

This is a little of the basic thread but,

I looked at your chisel and noted the serrated edge. If you don't mind me asking what is the serrated edge used for?

Jon


----------



## jimgo

jboart, I noticed that too. Actually, it looks like both the top and left-hand side (in the picture) of the blade were sharpened, with the left-hand edge also serrated.


----------



## SloopJonB

chucklesR said:


> The conjecture at this point is the gel coat issues are because the plates were not properly attached throughout their span and length. I'm not sure I get that, but there it is.


It sounds like localized hard spots causing point loading - similar to the way bulkheads will cause a visible ridge on the outside of a hull over time if they weren't set on foam or something flexible against the hull before they were glassed in.

Good luck with cleaning up that nasty glass - I don't envy you that job. Keep a powerful vac running near the tool head.


----------



## jrd22

They really didn't want that sucker to come out of there did they Chuck? Great thread, great pics. I'm afraid to show it to my brother, his boat has the same kind of plates.


----------



## chucklesR

The chisel is as described, it has one side of the blade sharpened and the opposite side is flat section for pounding on - so it can cut sideways as well as down.
The serrated is to cut i.e. saw. It's a very heavy duty tool I use for taking things apart. 
Dewalt makes it as you see it. This and a 1 inch wide thin blade cold chisel did most of the prying chopping, bending and such.

44Q


> After seeing the condition of the removed plate replacing chain plates has moved a bit down my priority list but when I do start the project it will be external plates bolted through the old ones. My only question is the number and diameter of bolts I should use? The plates are 3/8" x 2" x 24".


My rigger said "four bolts good, five bolts better", 1/2 inch SS with carriage style heads nicely polished.

Do NOT bolt through the old ones, seriously that makes no sense. You are going to pay premium bucks to put mirror finish plates (1000 or so a plate to get them nice) that have to be bent to the curve of the hull. That will mean chopping up both toe and cap rail also.
Then you are going to drill 5 holes blindly through the boat and at points up to 1/2 of stainless - the condition of which you do not know (after all there must be a problem or why install new plates).

Chop them out, fill and glass / putty smooth and install new plates at 250 each, no horizontal legs, just 2x24 with 5 bolts spaced to miss the rub rail. bolt through them. Cover the back with removable material or at least an access plate so you can inspect the nuts. Once every 10 years loosen it up and check the bolts/replace the butyl. 
Oh, and put a weep hole in so that the inevitable leaking water has a place to go intentionally rather than rotting wood that is out of sight.

Just saying, these are nice boats, might as well do them right. I do not ever want to be the 'damn previous owner'.


----------



## boz86

chucklesR said:


> The Navy taught me to write in BLUF style - bottom line up front.


Always laughed when I'd see a summary at the end of something that read, "BLUF." Someone didn't get the acronym.


----------



## chucklesR

boz86 said:


> Always laughed when I'd see a summary at the end of something that read, "BLUF." Someone didn't get the acronym.


Just because they taught me the style doesn't mean I use it well


----------



## Rezz

chucklesR said:


> My rigger said "four bolts good, five bolts better",


Animal Farm reference?


----------



## chucklesR

nope, he actually said that, in that way.

Then he rephased it - "well, five bolts would be safer".


----------



## davidpm

Thanks for taking the time to document your work so well.

Chuck you said: "No part of the chain plate actually touched the hull proper - just the three or four layers of glass and resin that where draped over it."

At first I didn't understand the above comment because it looks like the horizontal pieces were directly on the hull. So can I assume that you are referring to the vertical component that is away from the hull the thickness of the horizontal pieces?

Someone mentioned, that their should have been some soft material someplace. Are you still thinking that is important and if so where should it go?

The glass on top of the horizontal and vertical pieces, was it at the same thickness, how thick?

You said the stainless removed looked perfect are you saying, don't hate me for asking, the job was not necessary?

There was some discussion of the cause of the gelcoat cracks, has that ever been successfully figured out?

What do you suspect the purpose of that round bar at the top was? Maybe useful during installation. Seems it wasn't needed for strength.

Sorry about all the questions but enquiring minds etc. etc.


----------



## SloopJonB

David, something about your questions and comments gives me the feeling that you are looking for some rationale or backing for installing some chains that way - glassed in.

If I am correct, please disabuse yourself of any thoughts along those lines - AFAIK it is THE worst possible method of installing chains that has been developed since the advent of GRP boats.

If anyone knows of a worse method, please chime in here.


----------



## chucklesR

davidpm said:


> Thanks for taking the time to document your work so well.
> 
> Chuck you said: "No part of the chain plate actually touched the hull proper - just the three or four layers of glass and resin that where draped over it."
> 
> At first I didn't understand the above comment because it looks like the horizontal pieces were directly on the hull. So can I assume that you are referring to the vertical component that is away from the hull the thickness of the horizontal pieces?
> 
> Someone mentioned, that their should have been some soft material someplace. Are you still thinking that is important and if so where should it go?
> 
> The glass on top of the horizontal and vertical pieces, was it at the same thickness, how thick?
> 
> You said the stainless removed looked perfect are you saying, don't hate me for asking, the job was not necessary?
> 
> There was some discussion of the cause of the gelcoat cracks, has that ever been successfully figured out?
> 
> What do you suspect the purpose of that round bar at the top was? Maybe useful during installation. Seems it wasn't needed for strength.
> 
> Sorry about all the questions but enquiring minds etc. etc.


No problem David, that's why I post.

The only portion of the chain plates, vertical and horizontal that actually touched anything was a 1/2 inch or so at the bottom near the cored area of the hull. It was bedded in some time of light gray compound that Dremel'd away easy.

The glass looks to be from 2/8 to 3/16 thick - 3-4 layers and lots of resin - same everywhere. No apparent rhyme or reason. One heavier layer without so much resin at the bottom.

Ha ha ha. Yes, it was not necessary. These plates have and would have stood the test of time. On the other hand now I KNOW - and I'm going to do the rest as well. 
With me doing the removal and all the prep for installing the new (just vertical) plates, and a professional install I can get away with 250 for the plates and maybe 10 hours of labor, let's call it 2k. That's cheap for being able to sleep at night somewhere off 'tropical islands'.

At some point I will grind out the primary (pictured) spot of gel coat from the outside in until I run out of crack. I've not removed the plate over it yet - I'm a little leery of taking two plates off on one side quite yet - I've got a 1 mile trip and a haul out yet before they drop the mast.

I think the round bar, and the fact that it was covered in two layers of glass was put there to mess with me personally - I mean they knew I was coming. 
I found it by picking out all the 4200, silicone, butyl and other crap from above and pulling prying and scraping until I finally saw shiny bits at the bottom of the opening two inches of toe rail teak down. That and a lot of wiggling and wondering why it was not just falling out literally consumed hours. I'm going to call it a bastard bar even if I find out what it's proper nomenclature is.


----------



## SloopJonB

Sounds more like a buggeration bar to me.


----------



## davidpm

chucklesR said:


> The only portion of the chain plates, vertical and horizontal that actually touched anything was a 1/2 inch or so at the bottom near the cored area of the hull. It was bedded in some time of light gray compound that Dremel'd away easy.


I feel like a dog with a bone here. I'm trying to get a good mental picture of exactly what it looks like.

I operate under the assumption that whatever is done was done for a reason. The reason may be misguided, maybe wrong, maybe stupid but a reason nonetheless.

So are you telling me that the only the bottom half or less of the bottom horizontal bar was set in some sort of putty?
That would mean the the balance of the horizontal members were floating what like 1/4 to a 3/8 off the hull.?

This actually makes a lot of sense. From a fabrication point of view to make this christmas tree arrangement and have all the horizontal members lay tight to the hull would be very time consuming.

This also explains the bastard bar. It is welded on at an easily referenced point so the whole unit is shoved in from below until the bastard bar bottoms out and the bottom edge of the bottom horizontal member is puttied to the hull and you have your chain plate in positioned. Now just have the junior guy come after you and slap some glass over the whole thing and you are done.

So while the whole thing is evil from a repair point of view it makes sense from a build it quick point of view.

Not unlike hull liners on most production boats. Really stinks when you want to move deck hardware or fix wiring but saves lots of time in building the boat.

Do you think my scenario is plausible?
As to why the bastard bar was so thoroughly buried I've got this vision of junior being told to cover the chain plates so he figured he would really cover them. May not have been an engineering decision.


----------



## christian.hess

sounds like a stopper to me...good post above!


----------



## SloopJonB

davidpm said:


> This also explains the bastard bar. It is welded on at an easily referenced point so the whole unit is shoved in from below until the bastard bar bottoms out and the bottom edge of the bottom horizontal member is puttied to the hull and you have your chain plate in positioned. Now just have the junior guy come after you and slap some glass over the whole thing and you are done.


I think you've got it.



> So while the whole thing is evil from a repair point of view it makes sense from a build it quick point of view.


You've definitely got it.


----------



## davidpm

chucklesR said:


> At some point I will grind out the primary (pictured) spot of gel coat from the outside in until I run out of crack. I've not removed the plate over it yet - I'm a little leery of taking two plates off on one side quite yet - I've got a 1 mile trip and a haul out yet before they drop the mast.


I've got this video thing running in my head and I just can't picture a reason for that crack. 
You said on a another CP you cut into it and a lot of water ran out.

Maybe on the CP you took apart their was water n their and if froze and cracked the hull then leaked out someplace.
The stainless, one would think would show some signs of being wet for a long time.

Oh I think I read that you didn't open out the one with the crack over it. So when you do we will learn something else.
I hope at least one chainplate is near failure.


----------



## davidpm

As far a putting it back together goes I'm still seeing it going back together the same way it was put together with the following small tweaks,

1. The bastard bar is only their as a stopper and is not glued or glassed, doesn't need it.
2. The chain plate vertical is screwed to the horizontal pieces. The horizontal pieces are tapped so no nut is necessary.
3. The glassing of the horizontal pieces is done to leave a chainplate width area clear in the middle.

The only extra work is the drilling and tapping a few screws.
You put it together as a christmas tree and stick it in their and glass it in place.
Now any time you want to pull the chain plate just undo the exposed screws and drop it out. Should take about 10 minutes to pull a plate.
Adjust the width of the horizontals and the number and size of the screws to make sure it is a strong as a weld.

I know some folks have recommended putting in a knee and lots of boats have them but in my imagination I see disadvantages.
1. It is probably more work to do the knee.
2. It may introduce a hard spot on the hull.
3. You will have less flexibility on the cabinetry.
4. You will have some angles to work out if you change the plane of the chainplate
5. You may have to change something on the toe rail.

I'm just paranoid about changing too much on a boat that has done so well for so many years.
One it is always more work than expected due to reengineering.
Two I might not think of something.


----------



## Ajax_MD

I'm stunned at the amount of water that Chuck says comes out of these pockets.

Just...wow.


----------



## chucklesR

davidpm said:


> Do you think my scenario is plausible?
> .


Exactly. 
The implausible part is how the heck that held against the 1000's of pounds of pull. 
Fiberglass and poly-resin does not stick to stainless well at all. I did not have to grind it off, I simply pried it off (rather easily actually). 
The process to remove a plate was to cut around it, then pop off the glass, then cut through the stainless (simply to make it a manageable size).

I'm going to try and take the next plate out as a single piece.

Unfortunately that is on hold until the spar is dropped because I'd rather drop it with a plan than have it decide to just drop. I'm too chicken to take two shrouds off.


----------



## chucklesR

BubbleheadMd said:


> I'm stunned at the amount of water that Chuck says comes out of these pockets.
> 
> Just...wow.


I will video the next 'virgin' slice.


----------



## Faster

Based on what you've found... are you going to tackle the other side 'just in case'.. or to match what you're about to create now?


----------



## SloopJonB

chucklesR said:


> Unfortunately that is on hold until the spar is dropped because I'd rather drop it with a plan than have it decide to just drop. I'm too chicken to take two shrouds off.


You can replace a couple of shrouds with well tensioned halyards - as long as you stay at the dock. I've done it a few times with no problems.

It works best if you slack off their opposite numbers a bit so the athwartship tension is equalized.


----------



## chucklesR

That's the problem JonB, not staying at the dock - have to move it 1.5 miles up river, and then haul it out and put her on stands.


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## chucklesR

Faster said:


> Based on what you've found... are you going to tackle the other side 'just in case'.. or to match what you're about to create now?


Yes, I'm doing both sides, aft lower and uppers as well as the back stay. The fwd lower will be just a weep hole and inspection port (of some type). 
The fore stay is well mounted fully exposed on the end of the bow spit - no need to do it as I can inspect it and tell it's fine.


----------



## chucklesR

I got an update from Dylan ( DYLAN BAILEY?S YACHT Surveying Marine Surveyor Boat & Yacht surveys & Consulting St. Augustine, Florida)

His dad is also in the business and is doing the pull and replace of chain plates on a Irwin 43 in Norfolk. Mentioned it earlier, figured a reminder was called for.

Bottom line, On that Irwin 43, of the 6 chain plates pulled (aft lower, upper, forward lower - both sides). Of the six pulled 3 had serious corrosion - see previous pictures and posts.

Here's some photo's (inside, outside) of new plates installed - basically following the same plan that Jimmy C at The Rigging Company is recommending for mine.

The Rigging Company - mod's if I'm out of line holler and I'll remove the links, what I'm seeing with 11 plus pages is a lot of folks need and want information on this.

I like dealing with Jimmy, no bull, no sugar - and never assumes he's got your job.

You've seen the outside of my 38 CC (first post) l 43 CC is pretty much the same - here you see what a bolt through would look like. 


and here is the inside - note I've got *LOT* a lot of grinding to do


----------



## SloopJonB

chucklesR said:


> I got an update from Dylan ( DYLAN BAILEY?S YACHT Surveying Marine Surveyor Boat & Yacht surveys & Consulting St. Augustine, Florida)
> 
> His dad is also in the business and is doing the pull and replace of chain plates on a Irwin 43 in Norfolk. Mentioned it earlier, figured a reminder was called for.
> 
> Bottom line, On that Irwin 43, of the 6 chain plates pulled (aft lower, upper, forward lower - both sides). Of the six pulled 3 had serious corrosion - see previous pictures and posts.
> 
> Here's some photo's (inside, outside) of new plates installed - basically following the same plan that Jimmy C at The Rigging Company is recommending for mine.
> 
> The Rigging Company - mod's if I'm out of line holler and I'll remove the links, what I'm seeing with 11 plus pages is a lot of folks need and want information on this.
> 
> I like dealing with Jimmy, no bull, no sugar - and never assumes he's got your job.
> 
> You've seen the outside of my 38 CC (first post) l 43 CC is pretty much the same - here you see what a bolt through would look like.
> 
> 
> and here is the inside - note I've got *LOT* a lot of grinding to do


That's exactly what I recommended back in post #28. Certainly the simplest and most straightforward replacement.


----------



## jimgo

Chuck, why not build the area up, rather than grinding it down? You've got a lot less stainless steel distributing the load; wouldn't you want the fiberglass in that area to be beefier?


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## chucklesR

jimgo said:


> Chuck, why not build the area up, rather than grinding it down? You've got a lot less stainless steel distributing the load; wouldn't you want the fiberglass in that area to be beefier?


Sort of yes. One thing I have to maintain is the angle of the chain plate.

Here's a video of me cutting a tiny hole to drain some water.

Sorry, forgot to put on my makeup. 
Mod's feel free to edit, I don't know how to embed from my Google +

https://plus.google.com/u/0/116515354124197058849/posts/p/pub


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## endoit

Jimmy C at the Rigging company does a nice job. He did my chain plate polish 3 years ago and replaced my running rigging, placed a hydraulic back stay etc. Nice guy, knows his stuff and went out with me to check everything after install. Looks like your project keeps on going in the correct direction.


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## davidpm

chucklesR said:


> Here's some photo's (inside, outside) of new plates installed - basically following the same plan that Jimmy C at The Rigging Company is recommending for mine.


That looks nice and sure is a simple clean way to do the job.

They obviously got it to work but I've got a question about the process.

I'm assuming that the bolts we see are carriage bolts.
The head is in direct contact with the gelcoat.
I've used a lot of carriage bolts but always with the head on wood, usually soft wood. We would just drill a hole pop in the bold and crank on it until the head crushed into the soft wood.

In your case I suspect you would have to somehow cut the square for the head and be very, very careful in tightening the nuts as to not crush the gel-coat.
Probably very important to use a locktite product too since you can't really tighten them hard.
Is their a good chance that even if the bolts are perfectly installed that the heads under tension could cause gelcoat cracks?

Does that sound about right?

I'm also concerned that the chain plate is now only supported by the width of the CP and not by the full length of the horizontal pieces. 
The factory design was obviously driven by some cost factors but your through bolted design would have been even cheaper to do.
Do you think they went with the embedded design only to eliminate the bolts showing or maybe partly due to structural reasons?


----------



## chucklesR

Carriage bolts, yes. Backing for the heads- I'm hearing none needed. I thought of brass/bronze squares (done nicely). 
I've got no idea about the thoughts and intentions David; what I do know is I wish Irwin had done these 'normally'.


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## jimgo

I was surprised to see the "bare" bolt heads too. Perhaps there is a different kind of bolt that will be used, with a head similar to a carriage bolt?


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## lancelot9898

Chuck,

Did they give you a good explaination as to why there is no backing needed for the bolt heads? Seems like a good way to crack that gelcoat with the load concentrated on such a small area.


----------



## StormBay

Our chain plates use carriage bolts with the square collar removed. No cracking on the gelcoat as they don't have to be that tight. The pull is across the bolt not inline with the head...


----------



## davidpm

chucklesR said:


> Carriage bolts, yes. Backing for the heads- I'm hearing none needed. I thought of brass/bronze squares (done nicely).
> I've got no idea about the thoughts and intentions David; what I do know is I wish Irwin had done these 'normally'.


Yes if Irwin had made this easier it would be better. Its too bad they didn't think it through.

The idea of going external creates several problems, in my mind. Every job is a compromise so none of these problems may affect you.

The following are guaranteed:
The new chain plate will have to be bent to follow the curve of the hull and then bedded.
The new chain plate will exit the topsides differently and the toe rail will have to be fixed.
The new chain plate will have external bolt heads that will not be the original look.

The following are just my paranoia but might happen:
The bolt heads may distort the glass or gelcoat
There may be hull distortion due to point loading.
Someone looking to buy your boat may see a non standard repair and be put off from buying the boat.

The option of putting it back together the way it is with optionally machine screwing some of it together to facilitate removal for inspection seems safer and neater to me and when you add up everything maybe not much more work?

Please don't take my comments the wrong way. Your boat, your decision. You have lots of more experienced folks than I advising you. Just putting my internet 2 cents in which is worth probable much less.


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## chucklesR

David, the plates will not be bent, they will be bedded precisely on a curved bed. Theywill come out the same way at the same angle. I can deal with the look. Actually the look tells other owners of Irwin's I've take the time to fix a problem they still have 

The other stuff, it could happen. Point loading, I don't think so - when I bed the plates I spread the load plenty with a pad of glass of putty and ****. 

The option of putting it back was is a non starter, machine screws and all just makes no sense. I'd be right back where I am with no way to inspect.


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## AllThumbs

Chuck, I think your solution with the carriage bolts and no backing plate on the outside is fantastic.


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## chucklesR

Update time. 
I had to wait until haul out and deck stepping to get back to work removing chain plates.

The second one is now out - this is the starboard upper - it is under this plate that the original gel coat cracking was discovered. 
Here's the shots, but to save the drama - no signs of corrosion anywhere. Under the plates, same deal - no sign of any problems. 
One big note worthy of remembering -
In all of these pictures I've not done so much as wipe the plates, just shake off the dust from the removal "process".

Full length (minus 1/8 inch - it's easier to remove in pieces)



Closer up to the top - this is where most plates fail


Backside of the top


Backside of the bottom.


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## christian.hess

those look mighty fine...good on you for doing this preventatitve maintenance...Ill be taking some pics of mine and starting another thread for those interested in islander 36 chainplates and how they fail...

peace


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## jimgo

Chuck, so now the magic question...what caused the crack?


----------



## chucklesR

Probably water expansion, truly, I do not know.

I've already pulled the joinery and wood work off the other side there is evidence of leaking there - and a least one previous owner took out some screws and such to take a look (shame on 'em for not fixing it). 

My plan remains unchanged. I will take out the 2 lowers, the 2 uppers and the backstay, and replace them with bolt through plates.
If I find a single one of these plates with corrosion I'll reconsider doing the yoga contortionist and head/locker de-construction and do the upper stays as well. Other wise the uppers will only get a weep hole and inspection port.


----------



## chucklesR

Well it's been a while, but then it's winter outside.

I took advantage of the record setting warm weather just before Xmas and pulled the port side upper and aft lower chain plates. Despite having a large volume of water tucked away in the air gaps and hollows there was not a single spec of corrosion or de-lamination of the glass. 
In short, other than having water under and around the embedded plates there was no safety reason to pull them, the plates were fine and the glass was fine.

I put a 50 grit sanding disk on my grinder and sanded the entire newly exposed bulkhelds down to mostly flat and smooth in just under two hours total time for both sides. 13, 500 rpm does wonders that a conventional oscillating sander just can not do. Half inch thick ridges of fiberglass just powder away in seconds.

That's the bad part, the powder doesn't just float out over the side of the boat. I have a 1/4 of dust everywhere that now needs cleaning up despite the vaccuum and walls of plastic meant to contain it. 
I took a couple cell phone pics after a rough clean up but they are blurry as heck (so was I, it had been a full 8 hours of grinding, contorting and pulling/bashing. I crunched two finger tips when a previously stubborn plate gave way to a mighty pull.

Here's the only blurry one worth looking at - followed by what it looked like before sanding it down. 


Before sanding/grinding


----------



## Ajax_MD

You're a hard worker, Chuck.
I think it's really good that you're doing this. Think of the damage that those pockets of water can do, with the recent plunge in temperatures.

17F degrees today, and we might see single digits on Monday. I was shocked at the amount of water these pockets hold, so it's entirely possible for them to swell and cause damage.


----------



## chucklesR

BubbleheadMd said:


> You're a hard worker, Chuck.
> I think it's really good that you're doing this. Think of the damage that those pockets of water can do, with the recent plunge in temperatures.
> 
> 17F degrees today, and we might see single digits on Monday. I was shocked at the amount of water these pockets hold, so it's entirely possible for them to swell and cause damage.


I think that's the likely cause of the gel coat spider web like cracking I was seeing (what started this journey off). The amount of water observed coming out after the first slice of fiberglass is roughly analogous to the severity of the cracking.

For those keeping track, I've pulled four plates, originally I was going to pull 5. I've decided based on evidence in hand that I'm not going to pull the backstay at this point. 
The backstay and the two forward chain plates will instead have a weep hole engineered in (drilled, with a method to drain and inspect). I might get to them later. They present there own special problems based on location.

For example my backstay is offset to port of center, right where you climb up the stern ladder so it's in your face as you make the transition from the inverted cliff hang to flat deck. They offset it because the push pit stanchion is in the center. Poor design. When the time comes to replace it I will center it and move the gate not the whole balance of the boat.


----------



## arf145

Amazing progress Chuck! I think I'd still be procrastinating on that nasty work, but you're well on your way.


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## chucklesR

arf145 said:


> Amazing progress Chuck! I think I'd still be procrastinating on that nasty work, but you're well on your way.


Once the stick came down I couldn't/can't afford to procrastinate - I've got until late April to make it a sail boat again.

For my next trick watch me slap West system 105/406 and some filler into all the holes and then plaster some glass.

The hard part will be to make a raised landing that comes up/out precisely enough to support the new plate - but not enough to angle it too much, and it has to be flat and even or it won't distribute the load evenly. 
Oh yeah, and I have to do it four times.


----------



## SloopJonB

Wrap your new chainplates in packing tape and have them ready to go. Slather the thickened epoxy on the appropriate hull surface and slip the chains into place - they will custom form the exact shape of mounting base they want. Once the epoxy kicks you can remove the chains, peel off the tape and mount them permanently.

Another option is to wrap them in tape and mount them lightly in their final position - then trowel thickened epoxy in behind them. After it kicks and you remove the chains you can go back over the formed "landing" and touch up any voids with more thickened epoxy.


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## chucklesR

Thanks Jon, I was actually thinking I could wax my plates on the back and then they would not stick.


----------



## SloopJonB

If you go with wax, wax them all over, several times, not just on the "mating surface".

It's a messy job and the epoxy gets everywhere.

The tape seals things up well and releases well.


----------



## Total Chaos

The simplest way to replace chain plates and the one that avoids most problems has been mentioned several times. Through bolt the chain plates on the outside of the hull, little modification has to be done to the toe rail. The easiest way to do this is to bold through the existing chain plates... this does not have to be done blind, it can in fact be done exactly. Furthermore it does not matter significantly if the old chain plates have rusted or not. The old chain plates will be used as backing plates and provide far more than adequate compression even if they are have cracking or crevice corrosion. The bolts are combined with compression of the plates are what provides the massive strength. There is absolutely no reason what so ever to replace the backing plates with anything new. Remember compression is the key. I have seen many replaced with external plates and they look beautiful (to my eye) Crevice corrosion is the problem with glassed in plates as there is no O2 in there, I would never re-glass them in.


----------



## SloopJonB

In this case, due to the heavy cap rail and rubbing strake, that would NOT be the easiest or simplest method. It would require either complex bending & shaping of the chains or a lot of work cutting slots in the noted trim.

Bolting them to the inside of the hull in their original positions avoids all that. It does involve a lot of ugly cleanup work of the old glass though.


----------



## Total Chaos

I haven't looked closely enough in person on the 38 to tell how similar the replacement might be, but these are examples of the Irwin 65/68.


----------



## miatapaul

SloopJonB said:


> In this case, due to the heavy cap rail and rubbing strake, that would NOT be the easiest or simplest method. It would require either complex bending & shaping of the chains or a lot of work cutting slots in the noted trim.
> 
> Bolting them to the inside of the hull in their original positions avoids all that. It does involve a lot of ugly cleanup work of the old glass though.


And it avoids the Ugly bit of having the chain plates bolted to the exterior of the hull. I think it looks like a "cheap and easy fix" when on a boat that did not have it originally. It does make them easy to inspect though.


----------



## Total Chaos

You are still talking about adding a backing plate then to the outside of the hull right? Unless you use load distrubting plates like the original and reglass them, you would still need polished plates on the outide of the hull if you use any bolts at all. Am I missing somthing?


----------



## Stumble

miatapaul said:


> And it avoids the Ugly bit of having the chain plates bolted to the exterior of the hull. I think it looks like a "cheap and easy fix" when on a boat that did not have it originally. It does make them easy to inspect though.


That's because it is a cheap fix. I don't like external chainplates on any boat, but if I saw them on a boat that wasn't designed with them I would walk away.

The major problem with moving to external chainplates is that they have a larger failure area than on penetrating ones, and are covered in salt water much more commonly.

It really concerns me that people constantly want to mess with the work of a professional NA in such a substantial way without checking with a qualified expert. Swapping around chainplate locations is like moving around the structual walls of your house. Sure it might be ok, but it wouldn't do it without checking with an architect.


----------



## Total Chaos

The only neg effect moving the chains farther outside is on the ability to close haul, in this case it is only couple inches otherwise the plates are in the same location. The effect on the rig is to actually make it stronger... the base is wider. As to the cosmetics to each his own. The one absolute fact about glassed in plates is that they are 02 starved and water will get in there eventually, 30 years down the road, or 2 and along with that comes crevise corrosion. The only way to inspect these plates is to have gamma radiography done. $1500 just to inspect the plates, hmmm pass.


----------



## Stumble

Total Chaos said:


> The only neg effect moving the chains farther outside is on the ability to close haul, in this case it is only couple inches otherwise the plates are in the same location. The effect on the rig is to actually make it stronger... the base is wider. As to the cosmetics to each his own. The one absolute fact about glassed in plates is that they are 02 starved and water will get in there eventually, 30 years down the road, or 2 and along with that comes crevise corrosion. The only way to inspect these plates is to have gamma radiography done. $1500 just to inspect the plates, hmmm pass.


Not quite true.

1) moving chainplates outboard is only stronger if where the new chainplates are attached is at least as strong as where they were. Since very few boats use completely perpendicular spreaders simply moving them further outboard also changes rig geometry. Keeping them inline with the old rig geometry also likely moves the new chainplates to new attachment points relative to hull deck strongpoints.

2) if you think it's difficult to completely waterproof a 2"x3/4" hole, how much more difficult will it be to waterproof the outer edge of a 3'x2" plate with holes drilled in it.

3) dye testing is much cheaper, x-ray testing is also a possibility both at much lower cost. But I agree with you here generally, by the time you go thru the difficulty of removing them it is generally better to just replace them no matter what you find, since these tests don't address work hardening.


----------



## christian.hess

x2 above


----------



## Total Chaos

In this particular case.

1. The exterior plates would be just a strong as the oringal, stronger do to compression as the location on the hull does not change, expect as it is not directly on the inside of the hull, but now directly on the oustside.

2. Rig geometry changes are very miniumal as the new attachement is maybe an inch outboard.

3. The glassed in chain plate is oxygen starved, this combined with moisture is what allows crevice corrosion to occur on the plate. It would be quite fine for an external chain plate to leak as far as the intergety of the plate is concerned, but not so for a glassed in plate. If the internal plate leaks and the moister finds its way into a low oxygen environement that's bad news. 

4. Industrial inspection companies are all over, but in the US to inspect our chainplates with xray, really it's gamma ray that is used, ranged between $1100.00 and $1700.00 depending on whether they could do it in a full day or half day all of this done onsight at my location. These are US east coast prices and I check with half a dozen companies. 

I talked with two separate surveyors and both were quick to say forget the inspection and just replace them. One surveyor said that on any boat with thirty year old plates he has never seen an radiographic inspection come back that wouldnt recommend replacement anyway... ie don't waste your money.

4. External chainplates can be inspected, the internal, even if bolted on the inside can not with out tearing apart a lot of the interior. This may just be the case on my Irwin 65, but on her they are a serious bugger to get to.

All that being said many boats have the chain plates much farther inboard than on the Irwin. Moving the plates outboard on the hull on these guys could be a bad idea for some of the reasons Stumble mentions above.


----------



## christian.hess

I would never pay to have plates inspected especially at those prices, considering you can make new ones, beefier or not...or improved for less

keep up the good work op


----------



## SloopJonB

Total Chaos said:


> The only neg effect moving the chains farther outside is on the ability to close haul, in this case it is only couple inches otherwise the plates are in the same location. The effect on the rig is to actually make it stronger... the base is wider. As to the cosmetics to each his own. The one absolute fact about glassed in plates is that they are 02 starved and water will get in there eventually, 30 years down the road, or 2 and along with that comes crevise corrosion. The only way to inspect these plates is to have gamma radiography done. $1500 just to inspect the plates, hmmm pass.


I've seen gamma shots of chains on a big Irwin and they weren't enough to really tell the state of them. You HAVE to remove them to know if they are O/K and I pretty well guarantee that, after 25 or 30 years buried under glass, at least some of them won't be.


----------



## SloopJonB

Total Chaos said:


> 3. The glassed in chain plate is oxygen starved, this combined with moisture is what allows galvanic corrosion to occur on the plate.


They don't suffer from galvanic in that situation, they get crevice corrosion - a completely different process.


----------



## Total Chaos

Woops yes crevice corrosion... Ty

Sloop Jon -Exactly so why would anyone want to reglass a new set into the hull, you're just setting the next owner up for the same mess.


----------



## Stumble

Total Chaos said:


> Sloop Jon -Exactly so why would anyone want to reglass a new set into the hull, you're just setting the next owner up for the same mess.


Usually it's the cheapest way to go, often by a lot.

There is a legitimate debate about internal vs external chainplates,personally I don't see any advantage to external since they just change where the corrosion occurs. But let's table this for a moment.

The real answer is one of two options.

1) move to non-penetrating chainplates. This is becoming more common on new boats and is very welcome. Basically a metal ring is glassed into place and the turnbuckle attaches directly to that ring. No need for deck penetrations at all, not only eliminating the chainplate problem but also two holes in the deck.

2) switch to titanium instead of stainless. This is also being done more and more, and is a much better option for retrofit boats. The upside is that once replaced it is a permanent fix. They will never need to be replaced or even inspected in the future absent physical damage (someone hits it with a sledge hammer). The downside is they are a little more expensive than stainless, figure about 25% more for the parts.

This is an example of 1)


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## SloopJonB

Total Chaos said:


> Sloop Jon -Exactly so why would anyone want to reglass a new set into the hull, you're just setting the next owner up for the same mess.


You've got me.  If you read back through this thread you'll see that I am totally against the process - new or rebuild. In fact I am against ANY sort of metal being buried in glass - chains, floors, deck fasteners - you name it.

If one is replacing some chains done that way, as the OP is, I think they should go back in the same place they came out of, but bolted through the hull. Moving them to the outside does provide a slight benefit by putting the fasteners in compression instead of tension but since they are primarily in shear, that theoretical benefit does not begin to offset all the other negative aspects of the move.

Clean up the old glass  and remount the new chains in the same old place with bolts through the hull.


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## Stumble

SloopJonB said:


> Moving them to the outside does provide a slight benefit by putting the fasteners in compression instead of tension but since they are primarily in shear, that theoretical benefit does not begin to offset all the other negative aspects of the move.


It also increases the lever arm relative to the bolt attachment points, which increases the torque on the bolt head.


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## Total Chaos

When you bolt through the hull, are you placing a backing plate on the outside of the hull then? The head of the bolt is on the outside of the hull with the nut inside?


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## SloopJonB

I've never seen a backing plate used on the outside in that situation.

Remember, the primary force on a chainplate is UP, which puts the fasteners in shear, so a backing plate is of limited usefulness. Building up the hull laminate in the localized area would be more effective.


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## Total Chaos

Well I tell ya this has certainly given me food for thought. We are going to replace our chain plates this year and I was dead set on moving them to the outside of the hull and through bolting, I have seen it done on several 65's and I don't dislike the look. I have to say though I am going to re-consider my options. I may well go with the external plates, but I am looking hard at the idea of bolting through new plates from the inside. I will have a lot of interior work to do as a result of this anyway. Why this wasn't done when the deck/ hull joint was bolted and reinforced during refit I will never know. 

THANK YOU!!, to all the posters, none the least of which the OP. I can't say that I am to exited about this project, but it must be done.


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## chucklesR

The new plates will be in the exact same positions and angles as the old plates. Through bolted and not glassed in. 
I've worked out various redesigns on the interior to make it so they can be inspected without tearing out the side walls/joinery again. 

At some point, maybe, just maybe there will need to be external backing plates on the hull. My riggers tell me no, I'm not so sure. 
The primary reason I went for internal vs external was the cost - electro plated plates are x5 the cost - and not having to get a NA involved regarding angles of the plates, as well as not mucking up the (to me) rather lovely teak cap rail I JUST finished rehabbing and varnishing (down to bare wood and built back up).


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## chucklesR

BTW, I love the discussion on this.


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## SloopJonB

chucklesR said:


> The primary reason I went for internal vs external was the cost - electro plated plates are x5 the cost


Not sure what you mean by this. Were you looking at having them chromed? Or did you mean electro POLISHED?

If the latter, it only costs a few bucks - far less than the cost of the new chains being cut & drilled. It's well worth it too as the finish lasts WAY longer.

It also precludes crevice corrosion as there is no surface iron left to give it a path into the metal (as long as the electro surface lasts).


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## Stumble

Sloop,

Electropolishing only slows down crevice corrosion it doesn't stop it. But it is a significant increase in durability and well worth the extra couple of bucks.


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## SloopJonB

the way my polisher explained it, the process removes all the free iron molecules from the outer surface - to a very thin depth, less than .001".

That leaves the outer surface only the chrome and other alloys that comprise S/S so it does stop the crevice corrosion process until that thin layer eventually wears or weathers through, at which point normal corrosion processes start - the exposed iron molecules being the path in for crevice corrosion.

Getting the e-polishing redone every few years would keep it immune, barring damage.

The chains and floors I had done still looked like new after 7 years.


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## christian.hess

I had mine mirror polished...thats what they call it down here...its like glass...basically the top coat is melted down by buffing...you lose some thickness but because I had mine oversized to 3/8ths instead if 1/4 Im still way stronger

well see how long they last 

even if its only 10 years Ill be happy for sure


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## Stumble

Electropolishing is a process where the metal is submerged in an acid and an electric current is run thru the system. This causes the imperfections to be lifted from surface. Basically it is plating in reverse, but because of the way it works it takes high spots down faster than the bulk of the material. By removing the high spots and edges it also reduces the number of crevices that salt crystals can hide in, which reduces the speed with which crevice corrosion can occur. 


Sloop,

What you are talking about is called pasivation. Which helps bring the chromium to the surface. Since this is what provided the corrosion protection in stainless, the more surface chromium there is again the slower corrosion occurs. 


These processes are complimentary but very different.


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## chucklesR

All I know is mine won't be shinny except the tops. My current set aren't either - and they've lasted 27 years.


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## christian.hess

thats how I see it too

cept mine were shiny all around stock...jajaja


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## chucklesR

I got two warm days in a row so I made some progress. 
Using West 105/205 and 405 as structual filler I laid in filler in the center slot where there used to be an air gap that became a water gap. 
Keep in mind that the on old plates which were flat the only portion of the plate that touched the hull was the bottom 1/4 of an inch. What I need to do is build out a 'landing' for the new plates that will fit the curve of the hull and be flat at the plate. 
https://lh6.googleusercontent.com/-...AAAPCI/x0cGexsNduE/w1113-h835-no/P1010092.JPG

This is step one, in progress. Do some fill, then do some seal, then overcoat, and overcoat etc..


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## jimgo

Wait, I thought you had a dust factory. That almost looks like a boat interior.


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## SloopJonB

The quickest and easiest way to create the landing you need is to wrap the chains in packing tape, put a thick bed of thickened epoxy down where they will mount and put the chains in place.

Clean up the squeeze out and wait for the epoxy to kick. Then remove the chains, peel off the packing tape and you're ready to remount them.


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## chucklesR

SloopJonB said:


> The quickest and easiest way to create the landing you need is to wrap the chains in packing tape, put a thick bed of thickened epoxy down where they will mount and put the chains in place.
> 
> Clean up the squeeze out and wait for the epoxy to kick. Then remove the chains, peel off the packing tape and you're ready to remount them.


I agree, I'm getting the plates first week of March to do just that.


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## Aquarian

jimgo said:


> I was surprised to see the "bare" bolt heads too. Perhaps there is a different kind of bolt that will be used, with a head similar to a carriage bolt?


Our Vagabond has embedded plates with carriage-like bolts with no plates on the outer hull. Our bolts, however, have a slot - for a really big screw driver.

She has survived this setup for 30 years without any gelcoat damage. She also is due for a chainplates reveal.

Thanks huge for this thread.


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## flo617

I'm sure everyone will say it's a horrible idea but how about leaving the old chain plate in and bolt a new set through the old ones after cutting the stem that goes through the deck?

That way there is no need for the extensive surgery to take them out. One can grind slightly oversized holes through them and fill the area with epoxy before redrilling through for the bolts.

Wouldn't that work if the core of the chain plate is not completely compromised in compression?


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## SloopJonB

Might make it a little easier but it's what the British call a "lash up".

Here we call it quick & dirty.

A big, expensive boat should have something as important as chainplates done properly - it's no place to be cutting corners.


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## Aquarian

flo617 said:


> I'm sure everyone will say it's a horrible idea but how about leaving the old chain plate in and bolt a new set through the old ones after cutting the stem that goes through the deck?
> 
> That way there is no need for the extensive surgery to take them out. One can grind slightly oversized holes through them and fill the area with epoxy before redrilling through for the bolts.
> 
> Wouldn't that work if the core of the chain plate is not completely compromised in compression?


I don't think it is a bad idea at all, and I have seen it done well - on a Pan Oceanic. I met the owners several years after they made the change. They loved the set up - citing peace of mind in finally being able to inspect the plates as a huge factor. I believe that the change they made gave them stronger and safer chainplates. I also know that the original plates were accessed and assessed to insure future integrity, the rails were capped and sealed permanently, and adjustments were made to allow for drainage and drying of the original plates/spaces. and that the change was conceived and completed by a boat builder and engineer. I know this because I was working for the company that did the job.

I worked for this shipwright company in the Caribbean for a couple of years - one of the jobs I did was a chainplate conversion. I think that your location can affect your opinion in this situation. The warmer the water/weather, the greater the corrosion and clingy critter count, the more likely you are to approve of copper bottom paint, to forgo water cooled refrigeration, and to desire the ability to visually inspect your chainplates. We recently bought a resto boat from MD USA. The locals there thought quite differently from the folks we met and worked with in el Carib - and they were also correct. Perspective changes with geography.

It may very well be that the designers of these old tubs had no idea how much we would fall in love with them and to what lengths we would go to keep them afloat 30, 40, 50 years later. Had they known, they might have chosen a different design. According to the riggers I worked with, chainplates can often be moved safely outboard, but I would not do it without consulting a rigger. Changing angles on the rigging changes stress loads/points.


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## edakira

ChucklesR,

I have an 89 Irwin CC38 and am both amazed and depressed by your detailed documentation as you move thru this process. I'd love any current info you're gathering re pix and updates, and also wondering about access to the forward port/stbd plates? Mine (like yours probably?) are buried behind the v-berth bulkhead and seem extremely difficult to access from inside. And also, now that you're on the hard, the bow/bobstay plate down at the waterline? This thread has been extremely informative for me, thanks so much, and hoping you are progressing and soon back in the water.


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## chucklesR

Hey Edakira,

Here's a pic of the 'hole's' fiberglassed over, ready for new plates to be installed.
It just so happens that today is the day the rigging company is measuring and fitting for where to drill the holes; they want to both space them out visually nice and be strong enough. 

The forward lowers are indeed hard to get to. I'm not pulling them based on the condition of the four plates I did pull. Instead I'm going to drill a drain hole at the bottom of them, check the water out etc.. and make that a routine check.

The bobstay/dolphin striker plate is also fine, just rebedded. Aft stay is going to get a drain hole and inspection also. At some point I might do the forward lowers and aft stay simply by drilling through in place and bolting them similar to the new plates.

My interpretation of causal factors is: improperly maintained bedding of the chain plates allowed water to ingress into the cavities caused by less than stellar fiberglass embedding (lots of air gap). That water was pretty much in flow, i.e. not stagnant/oxygen depleted so the stainless was never compromised.


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## jimgo

Good luck, Chuck!


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## johnnyquest37

Just a thought, but you could leave the old chainplates where they are and rig new chainplates to the outside of the hull, or in the interior. Once you disconnect the shrouds from the chainplates, the old chainplates can stay where they are unless you are dead set on replicating the exact setup you currently have.


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## SloopJonB

Read the whole thread.


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## chucklesR

Speaking of the whole thread - sometime back I mentioned that I needed to build a platform for the plates because obviously the hull curves. The rigger said no, just a good flat surface and he'd bend the plates to the hull curve.

Guess what, now I need a platform/shim because a) bending 1/4 ss plate ain't so easy and b) doing so puts unacceptable pressure on my cap rail where the plate exits.

1 week to launch and all of it is raining.


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## Ajax_MD

What material will you use for a shim?

Metal? Epoxied-up wood? G10 plating?


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## SloopJonB

Back to wrapping the plates in packing tape and building a landing up with thickened epoxy.


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## edakira

An update from my end, ChucklesR. I just had my plates x-rayed (7 of 8 - they couldnt do forward bobstay down at waterline). An outfit that does oil and gas pipeline based in TX theyd never done a sailboat before. The images were very clear and revealing from top of plate down below "bastard" bar and below first of 3 cross bars. I had a local surveyor present to monitor and inspect images w the techs - who were all certified. We were very impressed and pleased w the results, and most importantly the plates all looked clean and free of cracks and corrosion. Cost me a hundred dollars per plate ($700) and makes me feel very confident moving forward w a Gulf crossing planned soon. I can upload a few images once I rcv from surveyor. So much gleaned from your in depth documentation of your own process and understanding exactly what we were looking for and exact plate shape etc. Here's a diagram of the forward bobstay FYI that I rcvd from Gene Gammon. Its from a bigger irwin but he said they were pretty consistent in style. Hope all goes well w your install. Obviously something I'll look forward to someday in the near future as I ponder the long term fix. --E


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## chucklesR

I wish I could have found someone to do x-ray's. 
I"m looking at a one week delay in launching which with other things going on (moving on boat) is going to really set me back.


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## Kiwijohn

Is there any posting on how this job turned out, in the end? I have a Cascade 36, similar arrangement but with a much heavier toe rail section and a good solid mahogany sheer clamp. I've religiously kept them sealed, but have no idea what the previous owners did. To mollify my nervousness, I was planning on cutting out the fiberglass "pockets" and making up new plates, with backing plates ( and carriage bolts) on the outside. The current plates are held in place with five, 3/8 dia, stubs, sticking thru the glass roving, welded to the plates.
Before I start cutting and grinding, I'd love to know how this project was completed.


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## Irwin54

I recognize that this is an old string.
I am looking at replacing the embedded chain plate for my headstay.
The boat is an Irwin 54 so the chain plate is at the base of the dolphin striker/bob stay.
Has anyone out there had to do this?

Thanks


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