Finishing the Foils

Once I had finished the hull and got it out of the garage and onto the trailer, I had bench space to finsh off the foils.  Most of the work was pretty straightforward but, as ever, there were one or two minor challenges along the way.

Probably the one that remains most noticeable is that - in order to get the Sunfish rudder head to fit - I had to sand back the head of the rudder foil through the first, very thin layer of hardwood veneer:

This is aesthetic only ..... but it niggles me.  The foil was made exactly to the specified thickness (3/4") but at that thickness the head wouldn't fit on - let alone rotate around its pivot bolt !  I took off as little wood as I dared and substituted the rather thick teflon washers (which you can now see used on the tiller bolt) for a much thinner pair make from milk bottle (in the US aka 'jug', I think ?) thermoplastic.  Seems to work - another thing to test in sea trials.

Once fully shaped (which included cutting the handle for the daggerboard and ensuring that the curve at the top of the rudder was good), the ply on both foils was given the mahogany wood dye treatment that I had given the decks.  This worked better than expected where the edges were shaped - except where I had had to use filler on voids.  The filler now stands out far more than I am comfortable with - all functional, though I suppose ...

Next, the foils were given a coat of epoxy, before I applied a layer of glass cloth on both sides and biaxial tape on the leading & trailing edges and bottom ends of the foils.  All of which went with several layers of epoxy and quite a bit of sanding !  They were then finished off with several coats of the same (Coo Var) yacht varnish that I had used on the decks.

I'm more pleased with the rudder:

than I am with the daggerboard:

although this is all aesthetics.  Functionally, they should both be sound.

A few more shots:

Daggerboard handle and mahogany deck stops:

Trailing edge:

leading edge:

Black dots on the leading edge were the 'cut to' marks on the glass cloth.  I forgot them until after I had squeegee'd on the epoxy.  Duh !

Much less filler on the rudder edges:

If I can find the right stock and some time over this winter, I may well replace these plywood foils with solid wood boards.

Daggerboard

The daggerboard diagram in the Sunfish class rules was much easier than the rudder one to take accurate dimensions from:

 I did have to take into account, however, that the distance between deck and bottom of hull (given as 13 3/8" for the Sunfish above) is different in the Moonfish.

Once I had the outline dimensions, I laminated two sheets of 12mm ply together using epoxy thickened with silica spread pretty thinly after prepping the boards with neat epoxy to prevent soakaway weakening the join.  I then marked and cut out the blank with a jigsaw, using a thin Starrett blade and drilled holes to get around the curves accurately:

This was then planed accurately to size all round, before marking out both the thickness and the depth of the foil edges:

These were then all planed, Sureformed and sanded back to the marks.  In doing this, I came upon quite a few voids in the ply laminations (but not in my glueline !) which I filled with filler and sanded back.  I lived to regret this later !  Sorry, no pics of the foil at this stage !

I did this work quite early on in the project, as the plans were very clear that the Sunfish foil was differently sized to the Moonfish ones and that the box in the central 'girder' of the frame had to be built to the revised dimensions.  The work this far gave me the dimensions I needed, so I left work on the daggerboard there until the end of the project when I finished off both foils.