Coach/pilot roof shapes using control points of related surfaces, inspired by the T-Splines plugin, which was also used for some experiments.
These sketches of a 70' Pacific proa were done in the process of learning Rhino CAD. Nothing is final. The basic parameters of the vessel were defined decades ago, the "saftey ama" to leeward is new, and there is still a lot of room for style (like cars!).
This safety ama is one foot off the water at rest, is engaged at 10 degrees heel and gets max. displacement (55% of total) at 20 degrees heel angle. At this size, that extra volume is useful for accommodations.