Ellipse solid strecthed using control points.
Uses a distorted 3D ellipsoid for the connecting "space" between the big hull and the safety ama, which has the same bottom cross section as the main hull but only 50% of its length, and with a spoon bow shape.
A lot of refinement still needed - cockpit area to windward, larger crossbeams, higher bows with more spring in the sheer of leeward hull(s), merge leeward surfaces of cabin to shed wind and water at same angle, central raised roof height and shape, etc., etc.
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.