I second Rob's thoughts. From the start, working from hull section lines, to a finished hull surface takes me about a week. The first surface is done in about two days, but close inspection reveals many defects. Several days of fiddling with the lines and redrawing surfaces are needed before I am satisfied.
I have not been very happy with the results when I tried tracing scanned hull line drawings. Even large scale (1:96, etc.) drawings have significant errors in the lines. Since the CAD model is 1:1 scale these defects can be very large.
I prefer to work from the Table of Offsets. I enter these numbers into a spreadsheet and convert them to decimal inch values. Then I export an XYZ coordinate file and import it into the CAD program. This gives the most accurate (but still not perfect) station lines for forming the hull surface. Of course, this takes another day or two to type and recheck the table values.
I generate many waterlines (intersections of horizontal planes with the hull surface, also called contour lines) on the hull surface (on a separate layer) and then look at them end on (down the long axis of the hull) to see defects in the hull shape. Even the tiniest ripple in the surface stands out with this method. After revising the station lines I regenerate the surface and create new waterlines. I repeat this until all waterlines come out as nice smooth curves. You can also do this with butt lines (intersections of longitudinal vertical planes with the hull surface).
I do not try to model the entire hull surface with a single grid. Of course, I build one side and mirror it. But I also create many separate grids. That way I can tailor each to meet the requirements of complex surfaces like a bulbous bow, or the transition at the end of the flat keel, etc.
How much detail do you intend to put into your CAD model? What is the smallest object that you intend to model? The amount of time and effort goes up exponentially as the detail size decreases. I am building a CAD model of the USS Oklahoma City CLG-5, in the 1971 configuration. I am working from original blueprints and photos, and the smallest detail is 1/4 inch (1:1 scale). There are many, many thousands of screw heads, bolts, nuts washers and rivets at this level of detail. My hull was built up with more than 500 individual plates like the real ship - that alone took six months to finish! Right now I have just finished the exterior wiring on a missile tracking radar. It took several days for this detail. All of the external lights on the ship have wiring, switch boxes, etc. Radars have wave guides and cables running through the towers. Lifelines and life rails are another very time consuming bit. I have been working steadily for five years, and I think I am about half done. At least half of that time was spent finding drawings and photos to work from. Note: I am NOT modeling individual wires in cables, the twists in ropes or the threads on screws. I may be crazy, but I am not stupid!
So, what is your goal and how much effort do you want to put into it? If you leave off the nuts and bolts and skip the wiring details you can do a pretty decent job in a year or two. If you want to generate images that look like photos taken on the decks of the real ship you will need to add all the details that a camera would have captured. These details will add a few more years to the job.
I am not trying to discourage you, far from it! It is best that you really understand the magnitude of the project from the beginning. That way you won't be disappointed part way into the project when you realize it will take much longer to finish.
And please, post more images of your work. I love to look at other people's CAD models. I learn something from every one.
Phil
http://www.okieboat.com/CAD%20model.html