Well, fellas, I can answer this one. As many of you know, I've been working on designing a Montana-class Battleship for the last year (or longer!) and I haven't found any better combination than the free "DelftShip" hull program, along with the inexpensive "Lamina" program for converting the hull sections to flat pieces. They both take a little bit of time to get used to, but the curve ain't nearly as steep as Rhino, Autocad, or any of the other serious 3-D softwares. About the only thing I wish I had, was a way to convert Sketchup files to 3DS files, but a guy can't have everything... Oh, and a couple more programs that have come in handy are the Siatki programs (both the free, and the paid ones) .
Links:
DelftShip
Lamina
Siatki (1.0.1 & 4.1)
Then again, I happen to be stumped at the moment, trying to design a part for another with no way to do it. I have it drawn in Sketchup, but I really have no way of modeling it in any other format that I can work with, such as STL or 3DS. If anyone is willing to help, I'll see that you get full credit...