Mark,

Warship hulls using NURBS is both my nemesis and sweet spot. I do not have time right now to go into any detail (but will soon) about how to help you.

I think that you are making things very hard for yourself by having too many curves (stations that is), that are irregular and with many points. Also, as said before (I zoomed past the thread), it might be counterproductive to generate the entire hull in one go.

British cruiser hulls nearly always display a knuckle at the bow. This you can add later and therefore disregard the part above the knuckle for the hull generation proper.

In my experience, it is better to work with longitudinal curves (waterlines) than with vertical sections (stations) and to use only as few as absolutely needed to generate the shape you want. Using curves with the absolute minimum number of control points also pays handsomely. 5 points are all it takes to control a simple curve, generally: begin, end, largest deviation from straight line and one point either side of it to control the curvature.

The stern is a more difficult area, but one that can be tackled rather painlessly using a combination of network curves, lofts, blends and sweeps depending on the case.

I will get back to this when I have time to work out an example.