The objective of this work is to develop an automated geometric modeler for trawler ships including a bow, for shape optimization purpose. Two approaches are tested to generate a spline-based representation of the hull. For the first one, a starting shape without bow is deformed to reach a target composed of points or lines, while preserving the shape regularity using a penalty functional. For the second approach, a starting hull including a baseline bow is deformed by handling meta-parameters, such as bow length, thickness or orientation. The different approaches are finally illustrated for a realistic application.