I think that some experimenting will be called for when I start on the light unit.

I have made a start on the construction of the model by cutting out all the hull frames.  I developed a method of marking out the shape when I did my Humber Sloop and have used the same method for Spurn.  The hull sections are shown below with the original drawing being 3/8 inch to a foot or 1:32 scale.  My model will be 1:24 scale.

The drawing is scanned in two halves, either side of the centreline with a couple on inches overlap.  Each of these images is then flipped in the computer so I have a mirror image.  Each image is then printed with an appropriate magnification to give me a complete 1:24 size cross section at each hull station, but taking account the thickness of the hull.  There is a bit of trial and error involved here with several test prints but it worked out at about x1.28.  The two parts of the section at each hull station can then be taped together and cut round just outside the line for each frame.  They are then stuck on the 5 mm plywood I used for the frames with Spraymount adhesive.  There are a few sample frames below.

The right hand image shows my first mistake, which I will explain in the next post.  The frames are cut out using my scroll saw and then trimmed to size using a disk sander

The frames were all cut out and fixed onto battens which can then be fixed to the building board, initially just using spring clamps.  I could then plan which area of the frames to cut away to allow access and space for the 12 V lead acid battery, servos and other electrical parts.  I drilled three of the frames to take the prop shaft as its much easier to drill accurately through 3 frames clamped together rather than spaced 5 inches apart. The bottom of each frame was notched to take the keel which is made from 3 pieces of 2mm ply laminated together.  There are three sections of keel which are joined in a mortice and tenon fashion for strength and stiffness.  Once I was satisfied everything fitted together the frames were bolted to the building board which had the hull centreline marked on it.  In addition I used a laser level to shine along the keel to ensure everything was straight.

The model will also incorporate a carrying handle in the centre of the hull.  This can be removed or slid backwards for access underneath it to fit the battery.  I first did this on Shemarah, a 1:24 scale Scottish trawler I built some years ago which weighed about 65 lbs when complete.  I discussed this with Dave Milbourn at the Warwick Model Show at the time and he told me it was a daft idea as the bottom would fall out of the boat if I tried to pick it up.  I sent him a photo of me holding the model, ballasted with bricks temporarily and he reluctantly conceded it might work.  I have now used this approach on three fairly heavy models and it makes carrying them much easier, if no lighter.

In the fourth picture you can see the mistake I make in drawing the frames.  I did not make the extension above deck level high enough for the stem of the hull to clear the building board so I have had to cut a slot to accommodate it.

Progress on Spurn has been a bit slow as a result of a short holiday and the need to do a few outside jobs before winter arrives.  I also had a couple of nagging doubts about the model but thankfully I have now resolved these and begun to progress the build again.

My first concern was my original plan to skin the hull with a mix of plywood sheet on the flat sections and cedar planks on the curved areas, which had been quite successful on my Humber sloop.  However after some thought I decided the limited flat areas on Spurn did not justify the complication and the complete hull will be covered with 3 mm x 10 mm cedar planks.  I have some in stock from building a 6M class yacht which came out quite well, although the planks wont be on display on Spurn as they will be covered by dimpled styrene sheet to represent the riveted hull plating on the full sized vessel.  To give you an idea of the look on the yacht here is a photo taken part way through its build.  All the planks on the yacht are tapered and there are no ‘stealers’

I have begun to layout the planks on the Spurn frames temporarily to get an idea of how they lay and twist and where they will need to be tapered.

The other aspect that was nagging me was fitting the motor and propeller, since the real Spurn never had one.  I have decided that instead of fitting an internal motor and conventional prop shaft and propeller, the complete propulsion unit will be mounted in a removable, torpedo shaped fairing attached to the keel.  The power supply wires will be taken into the hull through a tube, sealed into the bottom of the hull and open at the top about about 2 inches above the waterline.  Exactly how the ‘torpedo’ will be attached to the keel I have not yet decided but I will probably have to strengthen a couple of areas before the whole thing is planked over. Current thoughts are a couple of circular clamps around the torpedo tube which will need to be about 60 mm diameter to fit my available brushed motor inside.

Since you seem to like it Richard, here is a picture of the finished yacht, named Sirius, built to the John Lewis Petrel design from 1990.  I modified the keel and ballast weight to include a more modern ballast profile and the yacht has two alternative skeg and rudder arrangements to allow it to be sailed under radio control or vane steered.  Its 57 inches long and weighs about 27lb.

Ashley, an excellent idea.  I had thought of a couple of bolts/studs as typically used for model yacht keels.  Using them individually as busbars for the motor’s power supply is a brilliant twist.  I might well use the idea in some form yet to be decided.

Gareth

That looks a nice bit of weathering there Richard.  I always prefer to see weathered models myself and I remember a rather embarrassing moment at the CADMA show some years back.  After the demise of  Tom Gorman it was decided to ask one of the clubs to provide judges for that years show and Goole volunteered me and my wife as I had done the judging course at Haydock Park.  On the Kirklees stand was a beautiful small tug built by Alan Wyatt who you probably remember was a very skilled modeller and good friend to us. All his models were absolutely pristine and in the discussion with Elizabeth I commented that it was an excellent model but just too clean and tidy to represent a working boat.  Alan was not there at the time but his wife was, un-noticed to us, sitting behind the stand.  I looked up and saw her, obviously very annoyed by my remark.  She didn’t speak to us for the rest of the show but we did make it up eventually.