The intact stability of 27 fishing vessels, mainly from the Portuguese and Peruvian fishing fleet, are studied, after an overview of the International Code on Intact Stability (2008 IS Code, Part A). The variations of dynamic transverse intact stability of the fishing vessels under three operational loading conditions are calculated and analyzed for two representative longitudinal waves. The wave parameters considered were the following: s=l/20 and (a) λyLpp. © 2011 The Royal Institution of Naval Architects.