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.

Getting Ahead of Myself

I've got way behind with this blog and will work hard to catch up.

Today, however, is the Red Letter Day - completion:

Sorry - couldn't resist !

I still owe posts on the daggerboard, tiller, spars, sail and trailer and will get on to them directly.

(Just hope the 'Sea' Trials don't get in the way !)

And a Few More ......

..... gratuitous shots of her outside on the refurbished 1960s trailer:

A bit easier to appreciate the lines, I think.

Rudder

Making the rudder has caused me more head scratching than any other part of this build.  As allowed for in the Moonfish plans, I am using Sunfish rig and foils.  The challenge is finding out the exact dimensions of the foils - particularly the rudder.

The Sunfish class regulations give this information:

While there are enough dimensions to work out the size and shape of the bottom part of the foil, there is nothing about the size, angles, curve radii or mounting holes (for tiller, rudder head and tension spring).  In an ideal world, I would find an existing foil and just take the dimensions from it - but Sunfish aren't all that common here in the UK.

So what I did was find the clearest photos that I could of the foil and the rudder head/tiller on the web and print them out blown up to the largest size I could without loosing resolution:

By careful measurement of the photos (in both x and y axes, to take into account probable distortion of the photo views and printing/enlarging processes and all the necessary angles and radii) and comparison with the plan and the Sunfish rudder head and tiller plates that I had bought, I was able to rough out a hardboard template:

I then fitted the rudder head and tiller plates to the template which allowed me to refine the rough shape and position the three holes:

This whole arrangement allows the foil to kick up, yet be held securely in either the 'down' or 'up' positions without the need for lines.

The Sunfish class regulations give the thickness of the foils as 3/4" (+/-), which matches the gap in the rudder head.  To achieve a blank of this size, I had to laminate three sheets of ply: one of 12mm, one of 6mm with one of 4mm sandwiched between them:

which worked well after a night curing under quite high, but uniform pressure.

I then marked out the edges and shaped them down, mostly using a low angle block plane (with a small sureform in places), finishing off with sandpaper.  There were some rough spots left where some of the rougher filler laminations of the ply were exposed; I filled these with wood filler and then sanded back again to achieve smooth curves and corner radii.  The whole thing was then stained with mahogany wood dyes - as I had done on the deck of the hull.

You will see that the three mounting holes have been enlarged (to 20mm with a forstner bit).  These will be filled with epoxy before being drilled out again to the exact sizes.  This will give me mounting holes that are (a) more robust than bare wood and (b) impervious to water penetration.

Next up: finishing the rudder and making the daggerboard.

Well - hull complete, painted, varnished and fitted out !

 

No photos of how I got there, I'm afraid.  Hours and hours of filling, painting, sanding and fairing.  Not my favourite jobs (tho' critical to the final aesthetics) and not exciting to photograph.

The hull is painted in marine paint over marine primer (both ebay bargains).  The varnish is Coo-Var yacht & seaplane varnish, the white paint ordinary exterior house gloss and the red detail line is all-purpose exterior enamel.  Rubbing strips are varnished oak D strips from the local DIY store, fastened with bronze ringnails into the chocks (holes sealed with marine mastic).  The last photo shows the mainsheet horse and the sunfish-styled rudder fitting.

I need to get the hull onto the trailer (I still haven't posted about renovating that yet), so that I can clear space to work on the foils and spars.

Moonfish Hull Progress

It's been well over two months since I last posted.  While I've not been blogging, I have been making a fair amount of progress on the Moonfish hull.

This is where I've got to so far:

The hull is structurally complete, with all seams epoxy taped.  The cockpit was finished and painted before fitting the deck.  It has a watertight stowage compartment aft (the two forward hatches are for ventilation of the hull when stored), a hiking toe strap (made from an old car seat belt) and non-slip tape on the sole.  The paint is white domestic exterior gloss over two layers of epoxy. There is a layer of fibreglass on the sole to add strength and abrasion resistance.

So how did I get to here ?

 I had already pre-cut the four bottom panels, which now had a trial fit. No problems with the bow pair, but there was an issue with the after pair:

I decided to make a fillet for this gap. The first step was to mark out a rough template onto a length of paper (fax roll):

Once I had an oversized fillet cut from ply with the jigsaw, I then refitted the panels and took measurements of the width at 10cm (4") intervals, marked them onto the fillet and cut again with a Japanese hand saw. It was then a question of gradually planing it to fit until I had this:

The panels were then tacked into place with staples, trimmed to fit and the daggerboard slot opening cut. All the seams were then taped with parcel tape:

The hull was then turned over and the deck removed:

Then - a lot of filleting and epoxy taping .........

 This is not really exciting stuff (I much prefer the woodwork), but here are some photos:

Thrilling, eh ?

That done, I began fitting the cleats on all the bulkheads that both give them additional strength and provide bonding/bearing surfaces for the deck:

In the last shot, you can also see the additional 12mm support pad (so 24mm in all - say 1") for the rudder gudgeons.

The end result looked like this:

All this while, the deck panel (really flexible & flimsy-seeming) had been stored off to one side - you can just see it on the left in the pic above.  Now it was back on (upside down) to work out where all the deck fittings were going to go (I used the Sunfish class rules diagrams to guide me here), so that I could fit the doublers to support them:

I had to try to take account also of where the bulkheads and stringers would be, which I didn't quite get right (I forgot the width of the cleats in several places) and had to do some refitting when it came to fitting the deck right way up.

Then it was time to re-fit and epoxy glue all the side cleats (which had been on the deck when it was used as a building jig for the sides).  The builders notes said to use temporary screws to hold them while the epoxy set, but I used staples as they are faster and leave smaller holes to be filled and faired.  I put them in through bits of old ice cream cartons which made later extraction much easier.  Not my trick - one I found on the net somewhere - but it worked a treat:

Next came the paint job on the cockpit and watertight compartment, together with the fittings for which I needed access to both sides of bulkheads B and C at each end of the cockpit (the hatches and the hiking strap fittings):

The deck was to come next.  I really struggled to get it aligned properly with it in one piece. So,after much thought and with considerable trepidation,

....... I cut it in half again !

I realised that the join fell exactly astride bulkhead B at the forward edge of the cockpit.  This would give it more than adequate support, even if it did give me some minor fairing issues later on.

The deck was then glued down in two halves, held temporarily with screws into the cleats and staples into all the bulkhead and stringer cleats:

The stern half went on first; the bow half is shown above.

Once the screws and staples were removed, I planed and sanded all the seams to get a 1/2" radius before the taping work began again (exciting photo series warning):

So, there we are !  Next up will be sheathing the bottom.

There's some stuff to come, as well, about making the daggerboard and buying and refurbishing a 1960s-vintage trailer for the 'Fish.