Small waterplane area twin hull (SWATH) ships have been proposed to be used as recreational fishing vessels in order to enhance the tourist experience, attract tourists and improve the economic benefits of the recreational fishing vessels. A preliminary design scheme of a recreational fishing vessel is developed with the adoption of SWATH type and modular design concept based on the literature review of the disadvantages of the existing recreational fishing vessels and the advantages of SWATH. This type of vessel has the inherent good seakeeping and wind-resistance capability of SWATH and the flexible purpose conversion function. The above advantages are beneficial to the attraction of tourists and the improvement of the ship utilization rate. The conversion of the functional modules can improve the economic benefits of the recreational fishing vessel as it can be used for the shellfish harvesting, marine ranching duty and the marine fishery scientific research in the off-season. It is also the powerful supplement and the hardware reserve for the marine fishery research ship.