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[peter.stainton]

Hi All, I am fairly new to model boat building having spent the last 40 odd years designing building and flying RC model planes but this is stopped me dead in my tracks.
I have a Kit with a thin plastic hull, what I would like to do is build the hull plank on frame but how do I get the shape of the formers without destroying the plastic hull.  I have built three models boats plank on frame from plans but this time I would like to make a wooden hull plank on frame of a incomplete kit that I have been given.  The kit hull is of a very thin plastic, now without destroying the plastic hull how can I make a set of ply formers for the build. I suspect the answer will be obvious but at this time I cannot think of a accurate way.

[Neil]

you can buy from most DIY stores a small gadget called a profiler....it is a set of needles held in a steel frame and usually used by carpenters and such for taking profile shapes of skirting boards to match up the =nest piece. this can be used to take the shape of the hull at certain sections on the outside (half a hull side ( port or starboard) and then transferring the shape that those needles make onto timber.
 
see here     http://www.fine-tools.com/kontur.htm
 
neil.

[w3bby]

+1 on the profiler 

Buck and Hickman

[longshanks]

Hi,
What size is it and do you have full access to the inside?
 

[peter.stainton]

Thank you for the replies. The hull is about 32" and yes I do have access to the inside.

[Circlip]

Another one to try, a length of Solder. By carefully forming it to the hull profile and then transferring to paper and drawing inside the form.
 
  Regards  Ian.

[derekwarner]

  ....may be a little unconventional....but this will work
 
  Mount a digital camera securely looking down onto a table
Mount the plastic hull squarely flat & well supported on a substantial table
Fill the hull to say 10 mm depth with water dyed a bright contrasting colour to the hull ....take the first image
Repeat the filling steps at each 10 mm increment + next digital image etc until you reach deck level
Scan in each of the images in a Photoshop type program.....this will the provide a full set of water lines in plan view which can be transposed to end elevation views 
Naturally the accuracy of the successive addition of died water @ each 10 mm increment will be the factor on the accuracy of the water lines.......
  An alternate method would be to place the hull on a milling machine table that has X, Y & Z encoding
Run a dial pointer at say 10 mm from the base & encode the profile over the entire length
Repeat similar steps @ 10 mm height increments etc
The digitised file could then be used to provide the end elevation views <---------- + ----------->......................
  A third option could be to cut the plastic hull into 20 pieces & trace each section which would then provide an accurate profile of each frame.........Derek
 
 
 

[longshanks]

Fix the hull in a vertical position.
Mark off station points at regular intervals by fixing a pencil in an "thingy"
 
Form bulkhead templates at each station line. This is easier than it sounds, scribe your material in small sections. Start at the bottom. Get two bits right glue them together and carry on round.
 
 

[NFMike]

Just bear in mind that being thin plastic the hull may well be slightly out of true until the deck and possibly other stiffeners have been added.

[grasshopper]

If the hull is sufficiently stiff, and free of any internal structure, wax the hull insides,  float it in some cold water, keel supported and fill it, layer by layer with plaster of Paris or similar allowing each inch to harden. When completely full and hardened pop out your cast [size=78%] [/size]and cut into sections and Voila! Bulkhead shapes!



Alternatively do similar but making a female cast, supporting the hull over a suitable box and filling until casting material is level with deck edge - fill hull with suitable coolant to prevent warpage from heat when mould material goes off.


Another less messy method would be to adapt a pantograph and simply follow round the hull at the appropriate positions, obviously drawing a half bulkhead - the full section completed by tracing the first half.

[peter.stainton]

Thank you all for your help, what a verity of methods there is a selection of ways to do the deed. I will consider all the methods and probably choose more than one to get to the end result that I want.
Thank you all again shipmates.
Peter