The short answer to your question is that this shape is simply hand carved. Bogy, one third of our trio, is quite an artist and carved the plug after we had a sketching session where we came up with several profile sketches of what we wanted this version to look like - narrower than the previous ones and we wanted to try kicking up the bottom of the hull near the stern from the water (like modern catamarans). I wanted to draw it up in 3D on the computer and slice out bulkheads to strip plank build it but Bogy already had this plug and it was very pretty and already proved to be faster than the other versions we had made...it just needed a bit of fairing. So we moved forward with what we already had.