Models vs scaled up
The link worked for me, and they are talking about both models and scaled up versions, so that may be the source of some of the confusion. No mention of "scetches" there though :-)
Here's the intro that gives the context:
The current development trends for both model and full size yachts are discussed, and related to each other. The advanced development in the model field concentrating mainly on the Radio Marblehead class is explained, and the sailing performance of the models is examined. A test model fitting the RM class is produced and its design and construction process is explained. The sailing performance of the test model is analysed, and critical areas are established.
The test model is then scaled to full size and a wider model hull form is also scaled up, so a comparison can be established. The performance of the full size yachts are analysed using a V.P.P and a comparison between the two yachts is made. Other aspects of design such as motion and structural design are then looked at, and related back to the two different hull forms.
The hull and appendages of the scaled up models are then modified with regard to the previous sections, and values for keel length and sail area are looked at. The length of the vessel is considered with respect to accommodation and crew size. The application of the vessel is also considered and racing classes are looked at, and suitable classes are discussed.