Our half models are normally computer carved from the original design files.  Then we add the transoms, keels and rudders and hand finish using the original paint colour and graphics.  Finally we can mount the model on a mahogany plinth with the option of a brass plaque.  

If no CAD file available, we still manage!   Eg 1971 Carter, 1947 Rhodes and 1981 Q-T models we've made using a variety of information from old paper drawings, books and photos.