Part 1. The drawing and the plug
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Some notes about making a plug!
[2005-01-20]
Some people are absolutely convinced that it would have
been easier to make the plug like a planked boat.
Well, maybe for some. I found this way a good way to quickly get the basic
shape and then go on refining it. I have always found it easy to make a
shape out of only a block of something.
My first sailing models where all carved by hand, with no drawing,
out of a single block of foam then coated with epoxy and glassfibre.
Maybe you should find a better (thinner) material for the sections, like
2mm plywood or similar. And be careful with the rasp, its easy to overdo
that part.
But
if you are thinking about building a plug, think twice about whats easier
for you. Building a simple planked version and then using filler maybe the
easiest way.
I think i might try that the next time. If i cant find a computer mill...
Look here for a site with info on how he built a planked plug instead (in the project before this one, he used my method, hmm..)
The drawing.
I ordered the drawing from Sails Etc in the middle of februari and
recieved it about a week later.
It cost me 15 GBP. It's a two part drawing with full scale details
of almost everything, down to how to a detailed description of how to make make your own booms and
even sails.
Since i already got a quite competitive Marblehead i'm only interested in the hull and will keep my rigs and fin from that boat. More about my current boat later.
A small part of the very detailed construction plan.
Sails Etc describes the Monarch with these words:
"A close sister to ROK and PRIME NUMBER. A new Marine Modelling plan with a good deal of construction information. Needs to be built light for best performance. SAILSetc foils, fin box/mast tube, and deck mouldings can be used to complete a planked hull. Build it with the raised foredeck if you plan to use shroudless conventional rigs or with a flat deck if you plan to use swing rigs only".
My rigs are a mix of conventional Walicki rigs and swing rigs from Sails Etc so i will use a fin box cut for the Astra (i bought the Astra drawing and fin box last year, but never had the time to build the boat).
The fin box
You can build it with a planked hull as Sails Etc descibes it, but i
prefer moulding it in epoxy and carbon fiber. I built my current boat that
way, but i didn't make the plug that time.
So, that's going to be a first for me, for a Marblehead atleast.
This is probably the tenth model boat i will build.
After
photocopying the drawing i cut out all the sections and glued them on
wood-chipboard and carefully used a saw and a file to make the
sections as much like the drawing as possible.......
Right, the result that far
Now, there are atleast two different ways of
completing the plug. Either you make a planked "hull" and mould the boat
around that. Or you can put plastic foam between the sections and shape it
as good as possible, then mould it with fibreglass cloth and use filler and
sandpaper to make a nice finish, then mould the boat around that. I have
never built a planked hull so i went for
the second choice, wich i believe is also quicker. Not so sofisticated
since you probably will need some amount of filler.
But, the plug will
never sail, it's just the shape and finish that has to be right.
From
left to right in about one hour.
I used a saw, a rasp, sandpaper and my eyes to get it right. If it isn't right, well, filler in large quantities will come later...
This
is somewhere in between..
To make a stable platform for the plug i screwed it on a plank about one meter longer than the boat. In the picture to the right you can see the whole thing being held down by a clamp.
Next step was to cover my plasticfoam and
chipboard Marblehead with three layers of 300gr fibreglass cloth and
epoxy.
The plastic foam i used will melt if exposed to the much cheaper polyester-plastic or
usual plastic padding filler. So epoxy was the only alternative.
There are
plastic foam types that's suited for polyester. But they are so much more
expensive than this type made for isolation that the cheaper polyester
doesn't make up for it.
A
closeup right after the
three layers of fibreglass cloth.
After curing for a couple of days it was time for the sanding and filling and sanding and filling and...