Thursday 13 June 2019

More Work On The Centre Board

We last saw the centre board after it had received its lead ballast back in February, which by the way filled the aperture and its re-machined rebate very nicely.

I next removed the scrap ply backing pad, which held the lead in place during the pour.

You can see how the molten lead charred the ply pad. It bubbled and smoked wonderfully, as it did in the keel.

I used a Bahco scraper to fair both sides to a flat surface.

Next I filled the low spots on both sides with thickened epoxy.

And I then sanded both sides of the ballast to a smooth, flat surface, like this.

Then it was time to shape the edges of the board to a streamlined profile.

First I sprung a strip of thin ply to a fair curve along the trailing edge of the board, taking the line from the drawings. Like this.

Then I used the big Festool sander to shape the board to the profile indicated on the drawings. This was the result.

The leading edge now has a bullet-nosed profile, and the trailing edge has a long taper down to a thin edge. This will slide through the water nicely.

You can see that the edges are protected by epoxy armour which I added to a rebate cut around the edges of the board way back at the beginning of the build. Removal of material during the shaping has revealed the armour, especially on the trailing edge.

With hindsight I don't think the sander was the best choice of tool to do this. The board got pretty hot and I was concerned that the heat might damage the epoxy, but it seemed fine when it had cooled down. If I were to do it again I would use a plane and just finish with the sander.

After shaping I applied fibreglass cloth to both sides of the board. Here is the starboard side with its 'glass, curing.

The drawings say to wrap the cloth around the leading edge at this stage, but mine resolutely refused to stay in place.

So instead I added a strip to the leading edge when I was 'glassing out the bottom of the hull interior, like this.

Prior to this I had recoated the board to fill the weave of the 'glass cloth, and sanded it.

The board is nearly complete. It needs a couple more coats of clear resin and to be sanded to a very fine finish.

The manual says to leave it like this, as do other builders, but I am pretty well decided that I will paint it the same colour as the hull.

Others say that no one will ever see it, but it's actually really easy to see the keel or the board of a boat sailing in clear water. And I think as it is this board is not very pretty!

So it will end up being dark blue.


  1. Looking good! You are coming along quickly!

    1. Thanks Ron. It is getting to be fun again now that the filleting is done!