Centerboard

I didn't put a layer of glass in the middle of the foam blank, but in stead routed a groove in the middle of the aft side of the blank and filled that with putty. Before starting shaping the blank I marked the centerline on the putty fill.After gluing the blank I cut out the center spar, replaced the middle of it with a wood part as high density area and tried to figure out how thick the spar needed to be (taper). After the as always mediocre wrapping-exercise and the not-so-succesful attempt to keep the spar straight while curing the wrap, I tried to glue the spar back in position as accurate as I could. End of the story: it's harder than you might think to properly make and fit the spar.
After the fitting of the spar and after I had glued the HD-inserts in, I started shaping one side with a router..... I found shaping easier than on the rudder, because the centerboard is a bit bigger. I routed mainly in steps of 4 mm.

I didn't try to shape and laminate the centerboard in one go, as I did with the rudder. After shaping one side of the centerboard, I put the first layer of C on together with the carbon UD. While laminating this side I could keep the still flat side of the blank on a straight bench to make sure the blank would cure without twisting. With the sheating on the one side the blank is already quite stiff and strong. It's possible to shape the other side without too much flexing of the blank.

After laminating the second half + carbon, I did second (last) layer of C in one go, like this. I ran out of peel ply, so it's just plastic over the glass with some extra packaging tape to keep the glass in place round the pivot-hole.

Being afraid to make the board too thick, I made the recess for the carbon UD a bit deep, so I had to fill this area after laminating. I had good results using a piece of hard and stiff plastic to 'retrace' the profile (of course with two hands to make sure the spreader closely follows the profile and not with one hand as in the picture)
Recess filled. On the upper part of the centerboard I only filled the recess around the HD-inserts, as this will be the only areas that will bear against the case.

After curing of the first fill I put a layer on the whole profile of the centerboard (not on the upper part, as a smooth finish of that part is of no use). Now I only have to do some sanding, put on some primer and coat the board.

rudder(case) part 4 + trailer

Happy new year everyone. I made a bit of progress last few days.

Laminating the ruddercase with carbon was not difficult and a nice job to do. Below is the case with the stub shaped in foam.The tiller stub was the last piece I had to 'wrap' with cloth, luckily. I still haven't got the hang of it - and now I probably never will unless I'm going to build another fiberglass boat - and had a really hard time to get this piece right. I used vacuumbagging and also plastic and packing-tape in an attempt to keep the cloth in place, but it was not a big succes. Had to re-laminate the front of the stub.
Here's the end-result. Good enough for me. I have to glue&laminate the stub to the ruddercase and then I can finish & paint the rudder and the ruddercase.

I also bought an american-style trailer. It's very wide - only a few cm less wide than the maximum-width allowed over here. I'll probably have to add some extra tubes to be able to mount all the supports/rollers/etc.

Rudder(case) part 3.

I managed to reshape + laminate the leading edge of the rudder, so I could continue with the rudder case. Couldn't find a proper 4 mm thick plastic to mold the case. Instead I wrapped the rudder with the frontrunner fabric, and put two thin hard plastic sheets on top of that. Tried to mold the edge of the flanges with clay, but wasn't satisfied and instead just used an epoxy fillet (also handy to keep the mold plates steady). Once the case is out of the mold I can round off the fillet on the inside of the case.

It worked out well, although the case may be a tiny bit too 'loose'. I'll probably have to make the plastic block at the back of the case 1 mm less wide, to squeeze the case a bit together.
Couldn't think of a good way to put the glass spacer plate in the center of the molded case, and just guesstimated when I glued it on. To glue the tube properly alligned to the spacer plate, I put the case upside down on the rudder and used a piece of tube as can be seen in the picture below. I'm sure this method is not very accuate, but it was the only way to allign the tube I could think of.

In the meantime I'll also work on the centerboard. I wanted to use western red cedar as a core, but changed my mind when I found out in the Netherlands this is not the 'economy option'. Divinycell is cheaper. I think it's quite a big blade; should be easier to shape and laminate than the rudder.

Rudder part 2: FAIL

I laminated all layers (2 c-layers with the carbon sandwiched in between + extra layer round leading edge and top) in one go, hoping this would give the most compact laminate. Next time I won't, and just do one layer at a time. All the glass in one go is difficult.

Although the laminate itself came out ok, to my dissapointment the leading edge of the board has a much too big radius. I didn't take into account enough the thickness of the 3 layers C: to get the profile right I should have shaped the leading edge much more precise than I did.

I don't feel ready to throw away the rudder. Instead I'm busy shaping the leading edge again, this time hopefully right, and then re-laminate the front end of the rudder. Because I have to remove almost all the glass from the front till the carbon uniderectional, the carbon won't be totally enclosed by C-glass anymore (I mean: the layers under and above the carbon are not connected to eachother anymore on the front side), so the rudder might be less strong. I'll take the risk.

Rudder, part 1

I could found enough scrap foam to glue a blank for the rudder. Between the two halves I put some glass to make the blank a bit more stable.

Then I glued in the spar. I used fir (or was it pine?) as a core for the spar. Ian Farrier said that's ok, as long as you wrap the spar with the specified cloth.

Here is the blank with the still unsheated spar.

And here I'm gluing the spar in. Some small blocks under the spar (hopefully) keep it centered in the blank. I put some weights on to keep the blank straight while gluing.

The blank is initially shaped using a router. Grant used the same method. I've never shaped a rudder before, but I thought it went quite well this way.

The routed blank looks like a mess......

...but is actually not too hard to shape. I put some marker lines in the corner of the routed areas, and then it's easy to sand down. Just keep on sanding until the lines start to fade. I mostly used a surform to do the rough work, and a longboard to finish. In this picture the top half is nearly done. I was surprised how small (thin) the board is; because it's so small it feels like every mm mistake really counts - and it probably does.

End result so far: blank with 'HD' insert (mahagony) at front end. At the whole back of the blank, and the low tip of the blade, the foam is removed and replaced with putty. I also made the HD fill at the back with putty. This is easy to do because of the layer of cloth in the middle of the blank.
The rebate for the uni-directional with the spar in the middle of it make up a big portion of the whole board, and it feels like all the careful (ahem) shaping has been waisted. After glassing I'll check if the profile is still anything near the real thing and if not try to restore it with fairing compound.

Primer (finally)

I'm finally busy putting high build primer on the top exterior. This time I'm not spraying (too much hassle + needed a lot of thinner) but just rolling. I apply two thin coats in one go: this primer hardens so quickly after applying you only need to wait 15 minutes to be able to roll the second layer without messing up the first layer. I'll sand this layer down (grit 80-120), touch up the last spots (which show much better with the primer applied) and then apply one more layer primer which I'll sand with much finer grit.
One thing I learned is it is easiest to do as much rough sanding as possible within 24 hours. The primer is already sandable without clogging the paper too much, but not as rock solid as it becomes later.

Cockpit area cleaned and ready for primer. I'll try to finish this this night.
The corners in the cockpit-area will be high gloss and very visible. To get them nice and even I put on a new fillet after fairing the flat parts of the cockpit. Not much work and I think it will look quite good.

Some advice for builders shopping for hardware: if you've built up your bow (as I have) you need a trailer-U-bolt with VERY long legs to make it to the inside of the boat. I couldn't find a suitable U-bolt and will for the time being be using a simple eye epoxyed to a piece of M10-rod.

Interior primed, exterior work

Still busy fairing the interior and exterior. This is taking longer than I thought. It's a lot of surface, with all kinds of nasty turns, corners and edges.

Interior fairing is finished..

....and primed with normal house primer. The floorboards and the lid of the centerboard case will be made of some blue flightcase material I happened to have laying around. Still have to trim the centerboard flange.The exterior is almost covered with fairing putty. Still have to do the cockpit floor and the starboard cockpit seat. I did a rough sanding, and will do one extra run with putty and sanding to finish all the last spots. I won't try to get all the walking areas perfect, as they will be covered with non-skid. Will work hardest on the shiney areas (cabin sides & cockpit coaming & main bulkhead).Detail of the traveler, mounted on hardwood blocks.