I have also been using Excell for many years, and I have found that unless you are "expert" in the use of it, then to try designing hull forms is extremely difficult. As compared to a CAD package such as Mac surf and or Power Cadd, Excell is like going back and navigating your way through dos directories with the key board, as compared to point and click for a Macintosh! both do the same or similar jobs but the point and click was always much easier and infinitely quicker.