Forgot to add one interesting feature I noticed about the Viper. The stern section, unlike the taipan and A class flyer, has a very square profile, resulting in a very flat stern section.

In the light air, Greg had me sit far forward, in front of the front beam, to get this flat stern section out of the water. I'm not much of a naval architect or boat designer, so I'm not joining in the debate about longer waterline vs reduced wet surface area as i know nothing about either.

Feeling curious, I asked him why the Viper had such a flat stern section. I had the impression that perhaps the flat section was there to allow the cat to plane. His response was surprising.

According to Greg, he feels one of the flaws of current cat design is that current U shaped sterns makes it increasingly harder to sink the stern the more weight one puts on it (to get his exact views you might want to email him). This u shaped stern design seemed a little counter productive in strong winds as one would normally step further back to sink the stern and keep the bows up. So in effect the U shaped stern that is hard to submerge is working against the crew in a breeze.

In contrast, the squarish stern (with a tear drop profile) is at first difficult to press down, but once past a certain point, it gets progressively easier to sink the stern, making it easier to keep the nose up in a blow. I thought that was a brilliant idea, the only drawback being that the squarish stern does create more drag than u shaped sterns in lighter airs and the drag needs to be minimized by moving crew weight further forward.

I had to ask "Why not just make a narrow V stern so it's easy to sink in a blow?" Greg explained by having a narrow V stern, every time the boat hit a wave and raised it's bow, with a narrow stern, the boat would simply hobby horse. By having a square shape stern with a higher initial resistance to sinking, it helped to prevent hobby horsing.

How this relates to wetted surface area vs waterline length, I have no idea, but thought it was a really interesting design feature of the boat. Apologies for forgetting to mention this in my original post.