A technical note on the geometric representation of a ship hull form

In a recent special issue on ship design of this Journal the applicability of NURBS surfaces for ship hull representation was commented upon, as part of a review of challenges. The authors rightfully point out that NURBS do have their problems when applied to ship hull modelling. The review mentions T-splines as a promising solution, and concludes that the development of applications that address the NURBS limitations remains a challenge. However, just lifting out T-splines as the only solution can be considered to be a bit meagre, because many more alternatives have been proposed in the literature over the years. In addition, applications for ship design that overcome the limitations of NURBS surfaces do exist and are being applied in the maritime industry. As an extension to the special issue paper, in this short technical note the NURBS deficiencies are put into a context, and other potential solutions besides T-splines are summarized. It is illustrated that a viable alternative is offered by a hybrid representation method, comprising elements of a solid model and transfinite interpolation of an irregular network of curves, combined with curve fairing functionality. Because no single method is superb, suggestions for further research are formulated at the end of this note.