Spars, Mast Hinge, Part 4: Construction of G-10 Step

The G-10 step, ready for drilling
Having constructed a detailed mock-up step out of wood, it was now time for me to construct the real step out of G-10. This material - G-10 - is an industrial grade epoxy-cloth laminate. To put it in more basic terms, it's a solid piece of fiberglass. I had ordered from McMaster-Carr in Atlanta, Georiga a 12 inch x 12 inch piece that was 3/4 inches thick. Officially, on the McMaster-Carr website this G-10 was classified as Flame-Retardant Garolite (G-10/FR4). This Garolite, or G-10, I would cut to form two 3/4 inch pieces that together would be 1.5 inches thick. This was a much more cost-effective approach to this project than ordering a 1.5 inch piece. Now that the G-10 had arrived, I could get to work.

To cut the G-10 into the appropriately sized pieces, I used my Makita brand miter saw. This would ensure a nice, straight cut.
I used a 60 tooth carbide blade.
The G-10 gave this saw and this blade no problems. It was not unlike sawing sapele mahogany, which if you've read some of my other articles, is a dense tropical wood.

With this saw I was able to create two identically sized pieces that matched the dimensions of the mock-up.
Now it was time for me to make some marks. I started by marking the holes where I would mount the halyard plate organizer and the mast hinge itself to the G-10.
I used the reference marks to help me establish where I would drill the holes for screwing the two pieces of 3/4 inch G-10 together. These four holes could not, of course, interfere with the other four holes for the halyard plate organizer and the hinge. Therefore, I placed the marks for these four holes well out of the way.
I marked the center of these pencil mark references with a center-hole punch.
Then I walked outside with my sander and roughed-up the two faces of the G-10 that I would join together with epoxy. I used 40 grit paper for this, just as I did whenever I sanded cured epoxy or sapele mahogany.
It's difficult to tell from this picture, but the 40 grit paper created many small swirls in the G-10. It went from being green and shiny to being greenish-white and hazy.
I decided to use #10 wood screws to join the two pieces together. Accordingly, I used a 5/32 inch bit (two sizes smaller that the #10 screw at 3/16 inch) to establish a hole.
I then used a countersink bit to chamfer the hole. This would allow the flat head of the wood screw to sit flush with the surface of the G-10, or in this case, as I preferred it, slightly below the surface.
The G-10 proved to be incredibly resistant to accepting the threads of the wood screw.
Therefore, I re-drilled the hole one size larger at 11/64 inches.

After repeatedly screwing and unscrewing the first screw into the 11/64 inch hole, I was able to get it to accept the screw.
I then went around and did the same thing with each of the other holes.

Things were still a little tight, so I widened each of the holes on the top piece of G-10 slightly by routing them out with circular motions of the drill bit.
This enabled me to join both piece tightly together with the four screws.
In preparation for epoxying the two pieces together I sanded the top side of the top piece. This would be the side where the screw heads would sit. Since I planned for the screw heads to be slightly below the surface, and since I planned to fill the screw head holes with thickened epoxy, I needed the surface of the G-10 to be rough. This would help with the adhesion of the epoxy.
Prior to my mixing of the epoxy, I cleaned all of the relative surfaces with acetone.
I began by applying neat, i.e., unthickened epoxy, to both of the inner surfaces.
Then I thickened the epoxy with colloidal silica until it reached a peanut butter like consistency. I then spread it on the top of the surface of the bottom piece. In the picture below it appears that there is plastic on the top surface. What you're seeing are in fact the ripples of thickened epoxy.
I then set the top piece on the bottom one, screwed it into place, and applied clamps all around the perimeter. I made sure that the clamps were tight, but not too tight. I didn't want to starve the joint of epoxy. With the small bit of thickened epoxy that remained in the pot, I applied dabs to the screw holes to fill them up.
Concurrently, I began working on the anti-compression block that would go between the bottom part and top part of the hinge. You'll recall that I had determined that the anti-compression nuts available from Dwyer Aluminum Mast Company were not compatible with the original aluminum mast step of the Ericson 25.
I decided that I would use a piece of oak for the anti-compression block. This required me to plane down a piece of oak to the appropriate thickness - somewhere in the neighborhood of 7/8 inch.
I then used the table saw to get the material to the proper width.
One more cut - this one on the miter saw - got the piece to the proper length.
Then it was time for me to drill the four, 5/16 inch holes.
Also at this time I disassembled the block and thoroughly cleaned the original aluminum step.
It had been some 40 years since it had been installed on the mast.
There were pock marks here and there. It appeared that over the years small filings from the stainless steel hardware on the mast had fallen into this reservoir of sorts and created some corrosion from the interaction of the dissimilar metals.
By this point some days had passed and the epoxy on the G-10 had fully cured. With a quarter-sheet sander loaded with 40 grit paper, I sanded away all of the excess epoxy.
Yes, this was a time consuming process. Sanding epoxy, as I have said many times before, is like sanding concrete.

After I had finished the sanding, I did some work with the jig saw. Just as I had done with the mock-up, I rounded the edges of the G-10 step so as to make it less intimidating to lines and more pleasing to the eye.
I used Bosch T118B blades, which are designed for cutting metal.
Despite the quality of the blades, I did not get quality cuts with my Makita jig saw. Ideally, I would have used a band saw.
To make the cuts appear more uniform and professional, I rounded each of the four corners with the sander.
By the time I was finished, all four rounded corners looked symmetrical.
This G-10 mast step was now ready for drilling. For this I would need to call upon a friend with a drill press.
This ends this posting on how I constructed the G-10 mast step for Oystercatcher, my Ericson 25.

Spars, Mast Hinge, Part 3: Construction of Mock-Up Step

The mock-up base or step with the mast hinge and original step atop it
Having established that regardless of what I did in terms of a roller for the mast (at the bow) it would be necessary for me to build up the original base or step for the Dwyer mast hinge, I decided to construct a wooden mock-up before settling on a permanent solution.

When the mast hinge arrived in the mail, I took a few pictures of it. As I've said before, I purchased this piece of hardware from Dwyer Aluminum Mast Company in Connecticut. This was the heavy duty version of the hinge, Part Number DH2150. I also ordered the optional halyard organizer plate, Part Number DH 2890.
I was under the impression that the anti-compression nuts (number 4 below) were included with the mast hinge, but they were not. It turned out that this was not a problem for me, because I would not have been able to use them anyway due to the configuration of the original, aluminum Ericson 25 mast step that I would join to the top of the hinge. To compensate for the lack of the anti-compression nuts I would fabricate my own anti-compression block. More on this as we go along.
Even though this hinge was the largest one available, it was still a bit smaller than the original, aluminum step of the Ericson 25 mast. Fortunately, however, there was ample stainless steel material for joining the original step to the top of the hinge.
I also inspected the hinge mechanism itself, This hardware was simple and foolproof. The forward pin served as the pivot point. The aft pin served as a door bolt of sorts to keep the hinge shut when the mast was fully stepped.
With this hardware in hand, I climbed up on the boat and began to take measurements with the surveyors line that I had earlier used to determine the angle at which the mast would need to be relative to the hinge. Initially, I had hoped that I would be able to get away with a 3/4 inch buildup of the original base/step. Eventually, I determined that to be on the safe side, it would be better for me to build up the old base/step by 1.5 inches. It appeared to me that if I built it up by this amount, then I could get away with using the 2 x 6 bow roller assembly that I had constructed shortly before this time. In other words, I could avoid using an extension on the roller assembly - an extension that was impractical and unsafe.
All along, I knew that the best material for building up the old base/step would be the industrial grade epoxy-cloth material known as G-10. From my research I determined that the most economical approach to constructing a 1.5 inch step out of G-10 would be to order a 12 inch x 12 inch piece of 3/4 inch G-10 from Defender Industries in Connecticut. This I would cut to the appropriate size, and then I would join the two 3/4 inch pieces together with epoxy to make one piece of 1.5 inches. G-10 is not inexpensive, so I wanted the make sure with the wooden mock-up that everything would work as I had planned.
First, I determined that it would be good to cut the mock-up slightly longer than the hinge, forward and aft. This would help to distribute the weight of the mast. I also realized that I could not cut the mock-up slightly wider than the hinge. Otherwise, the halyard organizer would be useless. Additionally, as you will see below, I determined that I needed every bit of space that I could get on the port and starboard sides of the new base/step for the mast grounding wire and the mast wire conduit, both of which would be new additions to the boat.
To make the mock-up less intimidating to lines and more appealing to the senses, I rounded the corners.

The picture below is an excellent illustration of the complexity involved in the full refitting of a sailboat. Every project is interconnected with some other related and necessary subproject. Was it necessary for me to ground the mast? Yes, in this subtropical region of the United States in which I live, electrical storms are very common. How do I ground the mast? Where do I drill the holes? What size cable should I use? How should I pass it through the deck? Where will it exit the deck? Where do I route it in the main salon? How should I pass it through the sole of the main salon? How do I ground it in the bilge? Will the original, single grounding bolt suffice? I think not. Should I install a copper grounding bar? Yes, I think so. How long should this copper bar be? At least two feet if I sail in salt water, but longer if I sail in fresh water. I believe that one day I will trailer this boat to fresh water. Better make it longer than two feet. If I make it four feet, how would I join it to the underside of the boat? Where does one obtain a copper bar? Oh, I see, Does this company also sell the bronze hardware that I will need? No, they don't. Who sells bronze hardware? Oh, I see, Jamestown Distributors in Rhode Island is a good source, but they only sell it by the box full. I don't need boxes; I just need individual pieces. Oh, here's a place in New York state that sells it, but they only have part of what I need. Here's another place in another part of the country that sells the other part of what I need. Guess I'll have to pay the shipping for both. In my rambling here, I am not in anyway exaggerating the situation. I am in fact simplifying it. There are so many other things that I could mention, and I didn't even touch upon the through-hull that I installed in the deck for the mast wiring and the VHF coaxial cable. Why is it that so many people gave me such a hard time about how long this refitting of Oystercatcher took me? Because they themselves never fully refitted a sailboat. Anyone who has, knows exactly what I'm talking about.
Next I needed to determine the precise location for the mounting of the original, aluminum step to the mock-up. The new base/step could not be too far forward or too far aft of the original base. It also, of course, had to be centered on the centerline of the boat. Disregard the orientation of the old aluminum mast step in the picture below. It is oriented the wrong way. I had simply placed it aside casually while I was marking small reference lines on the deck.
Back inside, I prepared to mount the old step to the mock-up temporarily.
I drilled pilot holes, 7/32 inch in diameter for the 1/4 inch wood screws.
There were three of these holes for the 1/4 inch wood screws. One was forward and the other two were port and starboard. I then temporarily mounted the old mast step onto the mock-up with 1/4 inch wood screws. I did this so that the 1/2 inch hole that I drilled for the centerboard line would be as precise as possible. This 1/2 hole would be an important reference in the work I was about to do on the deck. For some reason I did not take a picture of my temporary mounting of the old mast step on the mock-up for the purpose of drilling this 1/2 inch hole.
I then drilled a 1/4 inch hole for the 1/4 inch machine screw that would pass all the way through the mock-up and into the deck. This 1/2 inch hole through the mock-up, just like the 1/2 inch hole through the mock-up, would be an important reference point in the work that was coming up on the deck.
Before I went back out to the boat I went ahead and drilled some additional holes in the mock-up. These were for the bottom part of the mast hinge.
These holes were 5/16 inch.

Back out at the boat, I removed the white duct tape from the old mast step and then thoroughly cleaned the area.
A close examination revealed that the old aluminum mast step had compressed the old mast base/step by about 1/16 inch on the forward starboard side. The new G-10 base/step would distribute the weight evenly across the old base/step.

Now it was time to align the 1/2 inch centerboard line hole and the 1/4 inch hole in the mock-up with their corresponding 1/2 inch and 1/4 inch holes in the old mast base/step.
Fortunately, everything lined up just right. Checking and then double-checking all my reference lines, I scribed an additional reference line, this one around the perimeter of the mock-up.
I would need to glue the G-10 base/step to the old mast base with much precision, if I wanted there to be enough room for the clam shell seal for the mast grounding cable (port) and the mast wire/coaxial cable conduit (starboard).
Before wrapping this part of the project up, I measured the thickness of the deck under the old mast base. It was 3 inches. My plan was to make use of the three 1/4 inch holes in the old mast base/step (the one forward and the other two, port and starboard) to help secure the G-10 base/step to the old mast base when I laid down the epoxy. I would use 3 inch long 1/4 inch wood screws. Since the G-10 would be 1.5 inches thick, this would give the screws 1.5 inches of grip in the plywood under the old mast base.

I marked the mock-up to remind myself about these 1/4 inch holes.
While I had all of this information in my head, I sat down and made some notes on the bottom of the mock-up to remind myself of the approach I needed to take in fabricating the G-10 base/step, and the approach I needed to take in joining the mast hinge to it (and the old aluminum mast step to the hinge itself). I should mention that in the notes I made, I referred to the old mast step, i.e., the piece of aluminum with the block in it for the centerboard line, as the "tabernacle." I also referred to the old mast base/step, i.e., the small oval piece of built-up fiberglass on the deck as the "mast step." As I have mentioned before, this conversation can sometimes be confusing because there are several different senses of the word "step." We can refer to that small built-up fiberglass piece on the deck as the step; we can refer to the new G-10 piece as the step; we can refer to the old, aluminum piece with the centerboard line block in it as the step; and, finally, when setting up the mast we can say that we are going to step it. At any rate, here are the notes I made to myself:

And here are a few final pictures that I made of the mock-up.

Notice the gap between the old mast base/step and the mock-up. My plan when mounting the G-10 was to lay down thickened epoxy in this gap. Then I would create a small fillet around the G-10 to increase the strength of the glue-up and to make the work more attractive to the eye.
Now it was time for me to get busy with the G-10.
This ends this posting on how I constructed the mock-up step for Oystercatcher, my Ericson 25.