On the beach the Viper looks like a stunted F18, whilst the Blade actually looks a 16ft cat.

Another aspect of the Viper is that they took their experiences with the Capricorn sailing downwind and fixed it up. The Capricorn in 15 knots plus had a tendency to want to pitchpole quickly or trip up when pushing hard compared to other F18s which would require drastic bearing away to stop a swim. In close F18 racing this is slow as you lose quite a bit of time and boatlengths. Changes to the rocker (location and depth) compared to the Capricorn makes the Viper a better all rounder.

But in relation to Goodall's comment repeated by Wouter about bow height. I am assuming that this applies directly to spinnaker cats. A-Cats are going the opposite direction with the A3 and the newly modded Flyer2 reducing bow height and bow area. However they are compensating by moving the front beam aft and increasing effective bow area that way but reducing overall volume.

And if the shadow with its 13sq m main and 10sq m kite is quick compared to the bigger sail area F16, well what does that make of my 8 sq m on the moth. Embarrassed a Viper completely last weekend in 10-15 knots upwind and down..... hehehe