The boundary tool uses 3 or more intersecting curves to build a surface. It looks like you're projecting a single curve. Change it 3 separate curves then project all three onto the surface. Switch to edit point mode, select a point on the "C" shaped curve then select edit curves-->detach curves. Repeat on another ep to create the 3 separate lines.

To get 4th boundary, use the edge isoparm of the ship.

Hope that does it...