Design Analysis Using Evaluation of Surf-Riding and Broaching by the IMO Second Generation Intact Stability Criteria for a Small Fishing Boat

Abstract

An evaluation was conducted to assess the surf-riding/broaching vulnerability of a 9.77-ton fishing boat by applying the regulations for stability assessment proposed by IMO (International Maritime Organization). Both Level 1 and 2 assessments were conducted and included a range of parameters along with the IMO second-generation intact stability criteria. In particular, it is considered three cases of wave forces acting on the hull for the surf-riding/broaching vulnerability Level 2 assessment calculations: (a) Froude-Krylov force (f(FK)) + 0.1M, (b) Froude-Krylov force (f(FK)) + added mass of the ship (M-a), and (c) Froude-Krylov force (f(FK)) + diffraction force (f(D)) + added mass of the ship (M-a). Previous results provided by IMO correspond to (b), and accurate calculation of wave forces helps to obtain more design margins. The design margins are high in the order (a) < (b) < (c), as described in the classification criteria. However, in certain cases, the assessment results may not differ significantly, so the hydrodynamic approximation assumption may be useful.