If anybody wants to make performance comparisons; here some basic data concerning drag of a catamaran. Source ; MissNylex C-class catamaran research

Platform
Form resistance hulls : 15 % (sailing on one hull)
Skin friction hulls : 22 % (sailing on one hull)
rigging/fittings/beams/hulls : 11 % (parasitic drag / air drag)
Crew : 6 %

Sail related forces.
Centre boards : 21 %
Sails : 25 % (parasitic - form - induced = 1% - 8% - 16%)


By making the hull more volumous we would incur a small increase in skin friction drag for light sailors (youth). Form drag should see only a smaller penalty as the wider hull will also float higher in the water. Note how close to 50% of the total drag is totally related to sail forces that are unrelated to the volume enclosed in the hulls.

Roughly speaking increasing the width and height of the F12 underwater body by 5% (Upgrading max skipper weight from 70 kg to 82.5 kg) would increase hull related drag for the 70 kg skipper by a mere 1.5%.

A 10% increase in both dimensions would upgrade the max skipper weight from 60 kg to 82.5 kg (110 kg displacement versus 132.5 kg) and leads to only 2.5% more overall hull related drag for the 60 kg skipper.


That is the lesson that was learned in both the F18 and F16 classes; increasing hull volume is pretty costless as long as it does't push the ready-to-sail weight over the minimum class weight. Although the Viper F16 is proving that in the way of overall performance the latter is not much of a consideration as well. More a marketing disadvantage. However I feel we still have some leeway with respect to the ready-to-sail F12 weight and the F12 class minimum.

Wouter