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.


  1. I just purchased an 1975 e25, and will begin a limited refit this winter. One of my projects will be to install a Tabernacle similar to the one you created. All of your postings provide a great roadmap for me to follow. One of my concerns with this project is the forward hatch that the previous owner installed appears to have a higher elevation than the one on your boat. I won't know until I get it into the shop and make some measurements. I look forward to corresponding with you in the future, and use your oystercatcher refit documentation on a daily basis. Thanks Aaron

  2. I always remove the forward hatch whenever I step or unstep the mast. Otherwise, there is not enough clearance. I address this in one way or another in other postings. I would think that the size of the modified hatch would not matter, unless of course the previous owner altered the fiberglass rim in some way. If he did, then I suppose you could make the G10 base higher than I made mine.