Rigging, Standing, Chainplates, Aft, Removal and Reinstallation

The original, aft chainplates, cleaned, polished, and ready for reinstallation
The aft chainplates, just like the forward one, often go undiscussed when the conversation turns to chainplates. When most people speak of chainplates they refer to the ones amidships - the ones that anchor the shrouds and thus support the mast. The aft chainplates and the forward one, however, are on the same team. They too anchor the rigging and thus support the mast. I've discussed the amidships chainplates and the forward chainplate in separate articles. In this article, I discuss my removal and reinstallation of the aft chainplates. All of these projects were part of the greater project of the refitting of Oystercatcher, my Ericson 25.
When I purchased the boat in the fall of 2009, this was how she looked after my friend and I had spent two nights aboard her in our transit from the previous owner's personal dock to Oriental, North Carolina for haulout. The Ericson 25, like many sailboats, has a split-backstay. In the picture below, taken in Oriental, we see the starboard side of the split-backstay anchored to the starboard aft chainplate.
Back at home with the boat in Charleston, South Carolina I gradually worked to refurbish, upgrade, and, in some instances, replace the spars and rigging.
My removal and inspection of the aft chainplates was something that I postponed for a long time. The primary reason for this was that there were other projects that I needed to complete before I could work on the chainplates the way I wanted to work on them. I knew that I wanted to install backing plates for these chainplates whenever I reinstalled them, and I knew that to do this I had to have good access to the hardware that held them in place. I had difficulty understanding how Ericson had installed these chainplates in the first place. There seemed to be no good access point to the hardware that joined them to the hull. From what I could tell, there was a fairly large cavity on the starboard side of the cockpit. I needed a place to hang docklines, so I figured that if I installed a small hatch in this area, then I could turn this cavity into usable space. At the same time, I would have full access to the chainplate on this side of the boat.
I purchased a Bomar brand deck plate, the outside dimensions of which were 10-1/2 inches. I had determined that this would be the correct size for this space after making many careful measurements.
As was the case with every other hole that I cut in this boat, I mulled over this job for a long time before I ever made the cut. Just like every other cut I made, however, I was instantly pleased as soon as I had made it.
I address this project more thoroughly in my article, "Docklines, Stowage, Cockpit."
For the port side of the cockpit I purchased a smaller Bomar brand deckplate appropriate for the available space. This deckplate would give me access not only to the aft chainplate, but also the stern navigation light and the stern rail. You can see one of the legs of the rail in the picture below. At present, the legs of the stern rail were simply screwed temporarily into place with wood screws. For more on this stern rail, see my article, "Stern Rail, Construction."
I had to replace the original stern navigational light. This deck plate would make the job much easier.

For more on this project, see my article, "Deckplate, Cockpit, Port Side, Installation."
In preparation for this work on the aft chainplates (and other pieces of hardware), I had ordered some 1/4 inch thick pieces of 12 inch x 12 inch G-10 from Jamestown Distributors in Rhode Island. G-10 is an industrial grade epoxy-cloth material. You can think of it as a solid piece of fiberglass. Many sailboat owners use it for backing plates, because it's easier to cut than steel, and it won't rot like wood will over time.
I made the most out of this G-10 by planning my cuts carefully. The circular pieces are for the winches, the rectangular for the aft chainplates.
I rounded the edges on these rectangular pieces so that these backing plates would be more kind to my hands when I installed them.
I sanded one side of the G-10 to make the G-10 more readily accept the epoxy when the time came to glue them into place. As it turned out, however, I would later opt not to epoxy them into place.
Now at last I turned my attention to the removal of the chainplates.
You should be able to see that access to the port side chainplate was almost impossible without this cutout that I had made.
When I looked through the cut-out I was troubled to see that the chainplate only had two screws that were through-bolted. The top two were simply wood screws that someone at the yard had screwed into the fiberglass. Whether this was Ericson policy or not, I do not know. What was more troubling was that the nuts on the bottom two screws were only hand-tight. Yes, I was able to unscrew them with my thumb and forefinger.
I wrote an astonished note to myself on the back of a piece of sandpaper to remind me of this fact. A friend and I have wondered many times if Ericson had a strong-armed dwarf on the payroll, or at least some athletically inclined 10 year old boy who did some after school work on a regular basis. I'm a regular-sized adult, and it was almost impossible for me to reach the bottom two nuts for these chainplates with a wrench in my hand by leaning awkwardly into the cockpit. Removal of the winches from the cockpit coamings was absolutely impossible. For this, I had to call upon a 15 year old boy. Even scrunched entirely within the cockpit locker he had trouble reaching the hardware.
The sealant for this chainplate on the port side had long ago dried out.
Despite the ugliness, the chainplate itself was in good condition. No cracks or corrosion.
On the starboard side I found the same thing - two wood screws on the top and two loose through-bolted machine screws on the bottom.
For some reason, the top two wood screws had washers around them that were stuck to the fiberglass, and the topmost one strangely had a nut that was sort of cross-threaded loosely on it. Make sense of that if you can.
Here's what it looked like on the interior of this space.
While I'm at it, I can't help but comment on this crappy repair job by the previous owner. It was clear that at some point in the past the boat had banged up against the dock in one of the many storms that had passed through North Carolina. This previous owner appears to have sought a quick fix to the problem - Bondo - that two-part paste used in auto repair shops. I can sort of get over that, but I can't get over the fact that he didn't even bother to sand the cured product to make the repair less noticeable. All he did was slap some mis-matched white paint on top of the dried, lumpy mess.
This chainplate, just like the other, had a lot of dried adhesive on it.
I removed the big stuff with a screwdriver.
Then I rubbed the chainplates down with toluene. This removed the remnants of the adhesive.
To get these babies looking their very best, I took them over to a friend whose passion is metalworking. He showed me how to work out the scratches with buffing pads on his pneumatic die grinder.
To bring them up to a mirror-like finish, we put them on a bench grinder with buffing wheels attached.
It took a while, but with plenty of buffing compound these pieces of steel starting coming around.

Back at home, I marked the G-10 in preparation for drilling the holes.

I made sure to mark these pieces of G-10. I was making a lot of other backing plates at this time, as I was wrapped up in reinstalling all the deck hardware.

On the boat, I gently scraped away, with a wood chisel, the large chunks of adhesive that remained.
Then I countersunk each hole. This would allow the butyl tape to form a gasket around the screws in these holes.

The top two holes on each side had never been drilled to 1/4 inch due to the wood screws that were used in the installation of the chainplates. Therefore, I had to drill them to 1/4 inch in preparation for receiving the 1/4 inch machine screws.
I used all new stainless hardware from my local hardware store. It's a great place - one of those types of places where you can still buy exactly the amount you need, and get some good help if you need it. There are two things that I did more than any other in the refitting of this sailboat - climb up and down that ladder on the side of the boat, and drive back and forth to the hardware store. More often than not, it would end up being the case that one of the screws needed to be 1/4 inch longer or shorter due to some variation in the thickness of the fiberglass. Then I'd be going up and down that ladder again and back and forth to the hardware store.
When the time came to put it all together, I began by doing a dry-fit with the G-10 backing plate.

This installation of the aft chainplates was associated with another project - the installation of the grounding cables for the chainplates. A friend and I had previously created these cables by unspooling 6 AWG boat cable and snaking it down from the area of the chainplates, through the lazarette and through the bilge to the bronze grounding bolt in the bilge near the mast compression post.
When it looked like everything would fit together well, I cleaned the area with toluene to remove any wax or adhesive residue that might remain. Toluene and its cousin, xylene, are good for this.

It helped to have this hole in the cockpit sole in the routing of the grounding cables. Ericson had used 10 AWG to ground the forward chainplate and the two amidships chainplates. I ripped this 10 AWG out and replaced it with 6 AWG, which is now the norm. For some reason - perhaps because of accessibility reasons - Ericson had never grounded the aft chainplates. The whole point of these grounding cables is to coax the lightning into following the easy path of the cables rather than trying to blaze a more difficult path through you.
I address the work surrounding the installation of these grounding cables more thoroughly in my article, "Electrical, Grounding Cables."
To seal holes underneath the chainplates, I used butyl tape. This is the good stuff that Maine Sail sells on his Compass Marine website. See the link to this website on the homepage of this blog. I used almost six full rolls of this butyl tape in the refitting of Oystercatcher.
A friend of mine who was helping me with this installation shoved wads of butyl tape into each of the holes.

Then we applied strips of butyl tape to the area where the chainplates would be in contact with the hull.

I cleaned all of the screws with acetone in order to remove the oil that remained from the machining process. Then I wrapped the head of each screw with butyl tape.
Now, at last, it was time to screw everything into place.
One of us stood outside the boat, the other crouched within the cockpit.

As per the instructions of Maine Sail, I slowly tightened the hardware over a period of about one week. This ensured that the butyl tape would be distributed evenly underneath the chainplates.
To finish things off, I gently removed all excess butyl tape with a wood chisel. This stuff, as Maine Sail says, never cures. It forever maintains its bubble-gum-like consistency. For this reason, I did not have to scrape off the excess. I simply used the chisel as a cutting tool to help me pull off the excess with my fingers.
Now I could call this project complete.
This ends this posting on how I removed and reinstalled the aft chainplates on Oystercatcher, my Ericson 25.

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