Hi Jim, I would prefer AutoCad with all the add ons but it is too expensive and the learning curve steep. I use TurboCad 15 but I think there is a latter version out. It is good for 3D and it doesnt take too long to get the hang of it.
Incidentally I did go back to the drawing board and took into account what you said about stability. Not sure how this might work out but I have pivoted the pilot's pressure vessel to the Cat section so that the pressure hull would be uniform in shape and as strong as possible I suppose there is tradeoffs with everything, anyway hope others like the new drawings and perhaps draw some other ideas from them.
Appreciate the suggestions, will keep working away on this concept...
http://www.psubs.org/projects/1280105118/voyagerdeepsea9mark2/