Rigging, Standing, Chainplates, Amidships, Removal and Replacement

The newly fabricated chainplates, polished and unpolished, side by side
Chainplates amidships are an essential part of the standing rigging of a sailboat.To them are connected the shrouds, the steel cables that help to keep a mast up. When chainplates fail, masts can fail. In this article I address my removal of the original chainplates and my replacement of them with ones that I fabricated with the help of my friends. How I did this for Oystercatcher, my Ericson 25, is the subject of this posting.
There were many things amiss when I purchased Oystercatcher in the fall of 2009.
I knew this at the time of purchase, and I knew it even more as time went along.
Nevertheless, I loved her from the start, and determined that I would give her my best effort.
When I got her to my home in Charleston, South Carolina from her former home in the Pamlico Sound region of North Carolina, one of the first things I did was to remove almost all of the deck hardware. I knew there were leaks, and I knew that I had to do something about them.
One of the problem areas was the starboard side chainplate. I began by removing the trim plate.
The bedding compound underneath it had long since dried out.
To remove the chainplate itself, I had to remove the 1/2 inch stainless steel hex bolts that secured it to the plywood bulkhead.
After this, it wasn't very difficult to pull the chainplate out of the deck.
I immediately saw that there were some problems with it. The area that had been concealed within the deck showed signs of corrosion.
Also the upper end of the chainplate was bent.
The port side was not as cooperative.

I had to use a block of wood and a hammer to try to break it free from the bulkhead.
Eventually, I wiggled it enough, up on the deck, with some pliers to break it free. This chainplate also looked bad.
There were many other projects that I undertook on the spars and rigging before I ever got back around to addressing the chainplates. First, I built four sawhorses to store the mast.
Then I replaced the wire-rope halyards with all-rope ones.
Then I got a rigger to replace the standing rigging.
I updated the old, obsolete Schaefer furler with a new one.
The old, wire-luff headsail for the obsolete furler was no longer viable. This led me to begin a conversation with a sailmaker.
I replaced the old spreader brackets and spreaders with new ones.
The mast compression post had problems. These I fixed.
There was no mast tabernacle for stepping the mast on this boat, so I had to install a new mast step and a hinge.
I removed the old traveler bridge and reinstalled it with G-10 backing plates. All of these projects I have discussed in separate articles, if you're interested in knowing more about them.
Now, at last, it was time to address those chainplates. A lot of time had passed since I had removed those original, bent and corroded chainplates. In the interim, my neighbor, in exchange for some beer, had made some new chainplates for me in his shop. At that time I had mistakenly asked him to make the chainplates just a little longer so I could add two additional bolts to them. The problem with this, as I later realized, was that there were obstructions on the opposite sides of the bulkheads that would prevent me from passing bolts through the bottom two holes. There were also some issues with the pin holes at the top of the chainplates. They were set a little too deeply for the toggle pins for the turnbuckles on the shrouds. For these reasons, I had no choice but to abandon these chainplates. I decided that I would, instead, use them as backing plates. The original set-up did not have backing plates. These backing plates on the opposite sides of the bulkheads would help to anchor the chainplates and the bolts to the bulkhead.
My friend who'd helped me on the mast hinge project helped me on parts of this project. Using his Makita chop saw with a metal-cutting wheel, he sliced off the unneeded ends of the oversized chainplate.
Then he used a grinder with a cutting wheel to cut the top side of the chainplates at an angle. This would ensure that they fit into the confined space on the opposite sides of the bulkhead.
He then used a less aggressive wheel to remove the burrs and soften the edges.
Using one of his bench grinders (with a buffing wheel attached) he polished the steel with jeweler's rouge.
Notice that the two backing plates are different in appearance. The one on the right was cut from the oversized chainplate that my neighbor had made for me. The one on the left was cut from one of the original chainplates. So much time had elapsed from the time that my neighbor had made the oversized chainplates, that when the time came for me to do this work, I could only find one of them. That's how chaotic my workroom/shop was at this point in the refitting. There were parts and pieces of this sailboat all over the place, not to mention scrap pieces of mahogany, G-10, aluminum, hoses, wires - you name it. Therefore, I decided just to use one of the old chainplates as one of the backing plates.
I had asked this friend to do a lot for me lately, so I decided to call upon another to help me with the fabrication of the new chainplates. This was the same fellow who'd helped me with the metalwork when I rebuilt my centerboard.
From Onlinemetals.com I had ordered a piece of 316 stainless steel. My friend used the one remaining original chainplate as a pattern for making the two new ones.
Using a bandsaw, he began by notching the steel, indicating where he needed to make the rip cut. Then he paused to remove some excess material.
To remove this excess, he executed a cross-cut. This made the new chainplates the appropriate length.

Then he began his rip cuts that would make the chainplates the appropriate width.
These rip cuts took a lot of time. Stainless puts up much more of a fight than plain old carbon steel.
This man loves to do metal work, so much so that when he took a break from performing the rip-cuts on the new piece of stainless steel, he polished the old chainplate, just for fun. At the same time, however, he was showing me what I needed to do to polish the other pieces of stainless steel that I had brought to his house on this day.
He used three different grades of polishing pads on his pneumatic die grinder.
Then he finished things off by taking the steel to the polishing pads on the bench grinder.
He turned me loose on the other pieces of steel while he focused on drilling the holes for the new chainplates. First, I worked on the original trim plates for the chainplates.

Then I worked on the backing plates. Yes, my buddy who'd cut these had polished them briefly with the jeweler's rouge, but he'd not given them a mirror finish. That's what I was aiming for now.
During all of this, I paused to take a picture of my friend's work on the drill press.
After he had scored each of the marked holes, he used the original chainplate as a guide for drilling the holes all the way through the new steel.
Just as was the case with the cutting of the 316 stainless, the drilling of it was slow-going.
After he had finished drilling the holes, he came over and set the new chainplates down beside one of the other pieces of steel that I had brought to his house on this day. The piece you see on the far left is the foreward chainplate. I address this piece of hardware in a separate article. Let us now, though, compare the polished steel to the unpolished. My buddy was about to bring up these unpolished pieces to a high shine.
Using his die grinder, he got to work.

After he had done as much as he could with the first one, he handed it to me, so that I could work on it even more with the bench grinder.
When I stopped, I asked him to hold the two pieces side by side, so we could illustrate the difference between the unpolished and the polished.
Then he started working on that second, unpolished piece.
In the process, he did not neglect the sides of the steel. These too were hazy in appearance.
This had taken the better part of an afternoon, but it was worth it. The new chainplates looked fantastic.
My buddy enjoyed that beer that I left for him.
Back at the house, on another day and time, I turned my attention to the chainplate cutouts in the deck of the boat. I would need to excavate the balsa core from these cutouts and then fill the cutouts with epoxy. This would prevent rot, if water ever made its way into the cutouts.
I began by digging out the caulk that I had squeezed into the cutout long before this time on the port side of the boat. Even though the deck was tented, it would still get a little wet every now and then during heavy fogs or heavy downpours. As an added precaution, I had taped the cutout with Gorilla brand white duct tape.
After I had removed the tape and caulk, I tested the fit of the new chainplate.
I had read many discussions online about the rebedding of chainplates. Maine Sail, whose advice I trust, had said that there should be plenty of wiggle room - as much as a 1/4 inch to 3/8 inch - on either side of the plate. This would allow for movement under sail, and it would allow plenty of room for the sealant. In this case, I would use butyl tape, the good stuff sold by Maine Sail on his Compass Marine website. See the link to this site on the homepage of this blog.
It did not look to me like I had near enough wiggle room for this chainplate.
I knew I had to widen the cutout, but I also knew that I needed to rid this area of silicone contamination before I did anything else. Maine Sail had spoken many times on many forums about the frustrations associated with silicone. It's a lousy sealant to use on a boat, and it prevents other sealants from forming a proper bond. Unfortunately for me, the previous owner had used silicone all over the deck of this boat in an effort to find quick fixes for more demanding problems. From what I'd read from Maine Sail, no solvent, no matter the strength, will ever remove silicone from the tiny pores of the gel coat. To remove it, you must use sandpaper.
I started with 220, but moved up to 100 grit paper.
Gradually, the sheen of the silicone and the gel coat gave way to a flat finish.
Now I could focus on widening the cutout. I began by making some reference marks with a pencil.
Then I attached a fiberglass cutting bit to my Dremel. I must say that this fiberglass cutting bit came in handy for countless projects in the refitting of this boat. It's a mean little sucker, with barbs all over its surface. It demands close attention, lest you lose control of it.

Satisfied for the time being, I now began to focus on the starboard side.

After I had enlarged the cutouts on both the port and starboard sides, I temporarily installed the chainplates to the bulkheads within the boat. This would give me a better sense of how they would sit after I had installed them for good.
This was a good move, because it revealed that the cutouts were still not large enough to allow for the appropriate amount of wiggle room.

I worked the cutouts once again with the fiberglass cutting bit.
Then I installed a small, 50 grit sanding drum on the Dremel. This I used to smooth out the rough edges of the cutout.
After I had completed this task, I attached a cutting head to the end of the Dremel. Specifically, I used a 115 cutting head.
This cutting head is 3/8 inch long. This is exactly the same thickness as the balsa core within the deck.
I would use this cutting head to remove all the balsa core around the perimeter of the cutout. This was a technique that I had learned from Maine Sail on his Compass Marine website.
Next I prepared to drill out the holes where I would reinstall the original trim plates.
I wanted to excavate the balsa core around these holes so that I could fill them with thickened epoxy.
I began by chamfering the holes with a countersink. This chamfer would later allow the butyl tape to form a gasket of sorts underneath the screws.
I then widened the holes to 5/16 inch. I did not drill all the way through the deck with this bit, only through the fiberglass skin of the deck above the balsa core.
I had to widen the hole to this diameter so that I could fit the cutting head into the hole.
When I was finished with my excavation of the balsa, I moved to the starboard side of the boat and did the same thing all over again.

I was still not satisfied with the wiggle room available for the chainplates. Therefore, I reinstalled the 50 grit sanding drum and got to work.

When I was at last satisfied with the width of the cutouts, I transitioned to the next stage of this project - the filling of the holes with epoxy. I had read online about some people putting duct tape or plastic on the interior of the boat underneath the cutouts, so as to prevent the epoxy from flowing down and out of the cutouts and holes. This for me was not an option, because the flange around the fiberglass hull/cabin liner prevented me from direct access to the underside of the cutouts and holes.
I had to come up with another solution. At last I decided to shove plastic down into the cutout. In doing this, I made sure that the plastic was well beneath the balsa core. This way, it would not hinder the epoxy from creeping into the core and sealing it.

I then taped the cutouts and holes with blue painter's tape.
This would protect the deck from any epoxy that I might spill.
I was concerned that the epoxy would seep down through the plastic, despite the fact that I had crammed the space as tightly as I could with as much plastic as I could. As an added precaution, I broke out the butyl tape.
I then shoved pieces of butyl tape down into the cutout.
I did this until I could see nothing except gray butyl tape.
All the while, I made sure that the gray butyl tape did not come up to the level of the balsa core.
When everything appeared to be well-sealed, I mixed up 6 ounces of epoxy.
Using a syringe, I injected the holes and the cutouts with this neat (unthickened) epoxy. This would make the balsa more receptive to the thickened epoxy that I would soon inject.
I mixed up yet another 6 ounces of epoxy, and this time I thickened it with colloidal silica to the consistency of ketchup. Using the syringe, I injected the thickened epoxy into all the relevant areas.
I over-injected the areas and allowed the epoxy to bulge upward onto the deck. This would ensure that if there was any seeping or movement in the hour or so that followed, the excess epoxy would fill the void.
A day or two later, after the epoxy had fully cured, I returned with the quarter sheet sander and 40 grit sandpaper.

Now it was time for me to reestablish the cutout for the chainplates. I began by drilling down into the cured epoxy in the cutout.
Then I used the small, 50 grit sanding drum on the Dremel to widen the space.
As I did this, I beveled the edges of the epoxy in the cutout. This would help the butyl tape form a gasket when I installed the chainplates for good.
It took some work to extract the plastic from the bottom of the cutout. This approach had worked well. Not a drop of epoxy had dripped down into the main salon of the boat.
Afterwards, I temporarily installed the chainplate once again.
This allowed me to check the alignment of the holes in the trim plate with the holes that I had filled with epoxy.
I re-chamfered each of the holes with the countersink bit.
At this point, I moved over to the starboard side and did the same thing I had just done on the port.

The cured epoxy was not quite flush with the deck, so I hit it with the sander.

While doing this work, I discovered a cavity that had not received epoxy. This I would fill with thickened epoxy.
Having completed that task, it was time to do the final installation of the chainplates.
Much to my chagrin, I discovered that the backing plate that my friend had fashioned from the oversized chainplate did not fit properly. The problem was that its holes did not match the existing holes in the bulkhead and the holes in the new chainplate exactly. When I tested the new chainplate, however, with the one remaining old chainplate, I discovered that their holes matched well. This meant that I needed to use this old chainplate for the new backing plate. This also meant that I needed to pay another visit to my friend who'd cut the first set of backing plates.
He cut the old chainplate down to size.

I then cleaned it up and buffed it at home.
This speedy approach with the angle grinder didn't bring the surface up to a mirror finish, but it brought it close enough.
Back in the boat I could now turn my attention to the installation of the chainplates. First I had to remove the old stainless steel washers that were embedded slightly in the surface of the plywood.
The backing plates would prevent this sort of thing from happening in the future. It should be clear by now that this boat did not originally have backing plates.
Here's how the bulkhead looked on the starboard side of the boat, inside of the head. This is where the other backing plate would go.
Just prior to installing the chainplates, I wiped everything down with acetone, just to remove all the remnants of the oils and buffing compounds used in their fabrication.
There were no buddies around whose aid I could enlist on this day, so I besought the Admiral for assistance. She pushed the bolts through while I tried to hand-tighten them on the other side.

There was, however, a problem. When is there not? The top of the backing plate still contained too much material. This was preventing me from getting the holes on the backing plate in alignment with the holes in the bulkhead.
Putting aside this problem for a while, I got the Admiral to move over to the starboard side of the main salon.
One of the holes in the new chainplate did not line up perfectly with the existing hole in the bulkhead. Therefore, I had to route out this hole just a tad. It seems that when my friend was drilling the holes in the new chainplates the drill bit had walked just a tad.
This worked.
Soon we had all of the 1/2 nuts and bolts securely in place.
Now I had to get to work removing some of the material from the port side backing plate.

That did the trick, for the most part.
It still, though, took some tapping with the dead blow hammer to get some of the bolts to seat.

At last, this part of the job was done.
Now I needed to seal everything up with butyl tape and install the stainless steel trim plates.
First, I cleaned everything with acetone.
Then I shoved butyl tape down into the cracks around the chainplate.

The cracks welcomed plenty of butyl tape, and I was glad to supply them with it.

When they would accept no more, I started laying the butyl tape down on the deck.

On top of this I placed the trim plate. I had to use long, pan-head screws. Recall that I had over-drilled the fiberglass on the deck. These screws had to reach all the way down to the layer of fiberglass beneath the area of the balsa core (now filled with cured epoxy). This bottom layer of the sandwich is what the screws grabbed.
I used a board to help mash down the trim plate and thus distribute the butyl tape. I did not want to strip the threads of the screw holes.
Then I worked on the starboard side.
On this side, after I had shoved the butyl tape down into the cracks, I decided to line the underside of the trim plate with butyl rather than laying the butyl down on the deck.
This helped to distribute the butyl tape more evenly. On both sides I was eventually able to get the butyl tape to squeeze outward around the trim plates and upward around the chainplates themselves.
At last I could call this project done.
This ends this posting on how I removed and replaced the amidships chainplates on Oystercatcher, my Ericson 25.