John Goodyear has drawn a very nice plan but I wanted to simplify the build method because effectively having two building boards seemed a bit complicated.  Borrowing Rays method of extending the bulkheads down to a datum I drew a curve in the building board to give the 12mm of sheer.  The datum would be zero at the bow and the stern and the height of the deck could be picked up by the amount of sheer at each of the bulkhead stations.  I then added 25mm to each one to get the hull well clear of the main building board and to make space for the temporary cross pieces holding the bulkheads in their correct locations during the rest of the build.  I hope this becomes more clear in the photos later.

Here the bulkheads have been photocopied and pasted onto 5mm medium hard balsa and the extensions have been drawn in place.

Here you can see that the bottom of the extensions are aligned with the edge of the balsa to save material and save some cutting.

Now the bulkhead have been roughly cut out ready to be sanded back to the lines and the holes cut out.  The external sanding was done using a Proxxon disc sander (lots of dust and a mask obligatory).  The holes were roughly cut out with a scalpel and finished to the lines using a Dremel with a small drum sander.

Like this.  Each one numbered according to the plan and the centrelines marked in.  Having centrelines is really important when building any type of boat except perhaps a Gondola!  In case the lines get rubbed out I pushed the sharpened point of a pencil into the balsa at the top of the line as a reference.

All the bulkheads were tacked to the cross pieces with small dabs of aliphatic glue and the centrelines transferred so they can pick up on the centreline of the main building board.

Tim R

Hello Richard

The build instructions suggest cutting out a flexible board the same shape and size as the deck plan.  This board is then pinned down at the bow and stern and raised with a 12mm packing piece in the middle to give the sheer.  Putting one piece of packing in the middle does not create a constant curve creates two straightish sections fore and aft with a sharper curve midships under the packer.
I generated a fair curve with a 12mm rise and plotted how much I would need to raise each of the intermediate bulkheads to bring them to same height as if they were going to be on the curved flexible board, but now mounted directly on the flat building board.  They were referenced and adjusted off a flat surface instead of a curve one and this leaves the hull shape exactly as before but with everything 25mm higher for convenience.  I hope this clarifies the process.

Tim R

Another modification along the way was to simplify the transom.  The plan shows a bulkhead just a little way forward of the transom.  The instructions suggest leaving the planks long to extend past the bulkhead and fit the transom afterwards.  To my mind this would be fiddly and would also leave a void which if ever got water in, would be impossible to drain.

This shows bulkhead 6 and the suggested transom.  I don’t know if the intention was to cut off the extended planks at the right angel and then stick the transom on?  This would mean sticking the planking onto the end grain of the planks and this would be a week spot.  If the intention was to fit the transom inside the planks it would be tricky to get a good fit.

I teased Ray about one of his plans not showing the transom detail and it is very easy to project if you paid attention during the geometry classes.  In this case however it was not necessary.

I saw that if you swing bulkhead 6 into the position of the transom it intersects the planking at almost exactly the same angle.  OK the geometry would not be 100% perfect but very close and seeing that bulkhead 5 was some distance away, the slight discrepancy would not be noticeable.

Bulkhead six now becomes the transom and is jigged at the correct angle taken off the plan with a scrap piece of balsa.  On check the height of the notch for the deck edge stringer it worked perfectly to continue the correct sheer.  It was only necessary to remove some material to account for the angle.

Now the planks can run past the transom to be trimmed off later.  There will be some gluing on the end grain but it will now be on 5mm wide balsa as supposed to the 2.5mm planking.

Tim R

Can’t wait to see the Slipper slipping along Ray.

Next Spooky step was to set up the bulkheads on the building board.  Just faintly at the bottom of the board you can see the sheer curve that I generated as a true arc.  Where the bulkhead stations intersected this arc gave me the heights required to get the bulkheads into the plan position.

Elastic makes a great clamping tool and doesn’t bruise the balsa.  Here the first deck edge stringer is being glued into place with the bow former being held in place with shirring elastic.

Next job was to make a jig to hold the extreme bow in place during the build.

With some little side brackets to keep the bow former vertical.

Tim R

Hi Chris
I was toying with the idea to put non-stick tape on the bulkheads and use them as moulds only.  My IOMs have no bulkheads.  In the end they re so light I decided to leave them in.  They are a bit fragile at first but after a few planks they stiffen up a lot.  I still might take them out (for drainage purposes) and just leaves the ones in place forward and aft of the keel.

Once I had got the bulkheads and bow former in place it was time to check the fairness.  This was done with a thin pine batten and I found that bulkhead 2 was undersized pretty much all round except near the deck edge.  There is an easy solution.

A thin strip of 1.5mm balsa cut across the grain bends around the bulkhead very easily with cracking especially when moistened by the glue.  I didn’t need all of the 1.5mm but it was very easy to sand down until the bulkhead was fair to its sisters.

Reading the build article the designer John said he introduced some flare at the bow to help prevent nose-diving when running before the wind in a blow.  All model yachts have this tendency.  Thinking about what he actually did was to hollow out the section of frame 1 which created the effect of flare but in fact had reduced the reserve buoyancy in the topsides.  So apologies John but I think this would increase the tendency to nose-dive.  If it was truly flared, the bow would look much more like the bows of the Fairey range of boats.  This is not a sailing boat type of bow.

I decided to fill in the hollow with an insert.

Which was left much larger than needed so I could fair it into bulkhead 2 and the bow former.

Having faired in one side I made a paper template so I could transfer the resulting shape to the opposite side.

Apologies for the fuzzy photo.

There are no more modifications in the pipeline for the hull so it was time to get on with the planking (also in balsa)

Tim R

Thank you Chris and Richard.

I have always enjoyed your evolving Fairey’s Chris.  There is a connection for me as I used to live in Hamble and have worked in one of Fairey’s old sheds.  My grandad had a Fairey Duckling which was the most horribly unstable boat I have ever been in.  In fact he also had the double version which clipped together if you were brave enough.
Thinking about it I amazed he did not put me off boats for life!  He also had a sailing clinker dinghy that was son flexible you could hear and see it twisting and an alloy speedboat that squirted water out of missing rivet holes.

I am an occasional reader of Model Boats and I am in awe of the detail and especially the weathering you manage to achieve.  I don’t think I have the patience but I am certainly going to have a go when I get back onto my Billing Boats Nordkap.

As for varnishing, that is my intended finish for the IOM that I am building in mahogany.  It is a lot hard to plank because the wood is not very forgiving.  The topsides will be varnished and below the waterline it will be white.  I haven’t yet decided how I am going to do the deck.

Your interest and comments are much appreciated.

Tim R

Spooky is now off the board.

Here you can see the centreline between the two planks very clearly.  This will be very useful for getting the rudder and keel in the right place and the keel accurately aligned for and aft.

This picture shows the tapering of the planks more clearly.

Next stage was to seal the inside with epoxy.  I use a finishing resin from Germany which is relatively thin and develops a nice hard cure.

The hull had a couple hollos that were too deep to fair out so I did end up using some lightweight filler.  Normally I have a modelling specific filler but that had gone hard.  The local hardware store had an alternative. it was 20% off and I found out why when I tried to squeeze it.  The bottom seam split through age so I had to transfer most of the contents into pot.

Luckily it is not much harder than the balsa so sands very easily.  This can be tricky when using car body filler which is much harder.

Tim R

Hi Ray

I think the stuff I got from the hardware was similar.  If it goes hard I will try the water trick.

The keel bulb arrived from SailsEtc today.  DF 65 A and B rigs with Soch Sails on their way.  I need the rigs before I can do that much more to the hull to do the mast socket and sheeting positions.

One problem with our move is that we no longer have test tank.  I am sure some of Ashley’s creations could be float tested in a shower but alas, none of mine except to see if the decks leaks!!  Maybe a dog paddling pool will have to do.  No problem with the dogs as they both hate water.

Definitely decided to fix the keel. Saves a lot of bother.

Distinct possibility for Easter which would make this one of my quicker builds.

How’s yer TID comin’ along?

Tim R

Spooky’s hull is strong and light but needs sheathing to give the outside some impact resistance and to provide a stable base for painting.

This is one layer of 78g / m2 glass cloth laid in epoxy resin. Being a very light fabric very little epoxy is required. I mixed 12 grams which was sufficient to coat the hull and provide compete wetting out of the fabric.  The fabric is very delicate and I find the best way to smooth it out is by hand with latex gloves.  There is no need to trim the cloth while the epoxy is green because a few strokes of fine sandpaper removes the excess quickly and accurately.

Here is another view.

It is better not to overdo the epoxy and only use just enough to make sure the cloth is fully adhered.

This is some slightly heavier cloth that was used at the stern where the rudder tube passes through the hull.  It is really just a precaution against the rudder taking a knock.  I would prefer the rudder to be damaged rather than the hull.

I also laid up some even heavier (still light) cloth right across the hull in way of the keel.  This section also carries the mast loads.   The hole was traced around the carbon fibre helicopter blade that will be the fin.  The plan shows the keel as removable but seeing as I hardly ever take any keel off I may decide to fix it.  This is not a big boat.

Tim R

The rudder on the drawing is rectangular.  I have never seen a rectangular rudder on a full-sized racing yacht so maybe it is a RG65 thing?

Mine is going to be a little different like this

It is made from a single piece of plywood that fortunately was flat.  The carbon stock is a fraction wider than the plywood so to get it in the middle while gluing, I stuck layers of tape either side of the slot where the thickness of the tapes came to half the difference in the stock diameter and the ply.  That meant I could assemble onto a flat surface and get the stock accurately centred.

The play was rounded off on the leading edge and tapered along the aft edge.  The difference between the stock and the blade was blended out with polyester filler so that you end up with a nice aerofoil.

The carbon fibre stock was a close sliding fit in a piece of anodised aluminium tube (no brass on this boat)

Tim R