From the wally site:
A private island of unimaginable space, light and tranquility, it is the worlds most stable hull and provides an entirely new and superior way of living on the sea. Designed for low energy consumption it is also a breakthrough in efficiency and environmental responsibility.
At this size and shape the boat almost looks like a building, which begs the question which software would make sense to design it in. A project like this would be a perfect test for a hybrid collaboration of engineering (Nautical) & BIM (Building Information Modeling) software working in harmony.