I have been working on ship hulls for museums. The basic requirement is to be within 1/32" of the design so my parts will fit with other parts. Most tutorials I have seen on hulls involve those that are simple or done freeform. I found one olde video that addressed some of the problems here using T-Splines. I presume that Subd might then have the same underlying capability but the Subd commands appear to be exclusively designed for freestyle modeling. I suspect the shaft bossing and triangular areas would be no problem with the right Subd interface.
Here is one of my hulls. It is a patchwork of surfaces because the hull form changes. At the bow, the hull is S-shaped and network surfaces. Forward of midship, the upper cross sections are straight and the surfaces an edge surface.
Aft of midship, the hull is in three sections with knuckles.
In response to Rhino words of wisdom I have seen on the Internet.
“Don’t use Networksrf”: If I want four defined edges and the interior needs more than basic definition for precision, it’s the only thing that works. Sweep2 frequently causes ripples from hull frames.
“Use Single Span Curves”: There is no single span curve of reasonable order that defines the hull shape within 1/32". At degree 51, there is more than an inch of deviation. I can spot 1/8" deviation visually. I used RebuildCrvNonUniform and get 40 points to stay within tolerance at the bow.
The stern is where things get messy. Below the upper knuckle, I get a three-sided shape. I cut an opening for a rectangle so the surfaces have four sides.
At the twin keels things are the craziest. It is chopped into many pieces to get four-sided surfaces. At the lower aft edge of the twin keel I cut out a section to get four sides. I have a small cutout to make a four-sided shape .
In a few places I was unable to get a four sided surface to work at all. There are 3-sided shapes on both sides of the shaft bossing.
The outer shaft bossing is extremely dense even though the curves are lines and arcs.
I would love to be able to add overlapping plating but have not found a practicable way of doing it in Rhino.
In the end I get smooth seams where I want them. I wish it were a bit simpler.
Shelling is a nightmare.