Hi
I would do it from a frontal view, extrude and adjust as going from stern to aft. But only for one half. I did this for the little avatar boat.
I also used lattice deformation and sub-surface.
But with the motorboat simulator I got this demo CD from Stentec with also freeware to produce hulls aand sals. the se export to VRML and you can import them in blender. This makes it all a lot easier. I'll sent you link later.
/Alex