This paper proposes a parametric modelling method based on Knowledge Based Engineering (KBE) for an LNG bunkering vessel (LNGBV). Parametric models aim to define the geometry and main systems configuration of the vessel starting from the principle that the vessel should be able to perform its mission successfully. The adoption of KBE in combination with parametric modelling is expected to improve the current practice by automating the generation of the parametric models based on the design requirements. The results showed that different design alternatives can be rapidly generated which in turn gives the possibility to the designer to perform a wide exploration of the preliminary design space.@en