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 (fFK) + 0.1M, (b) Froude-Krylov force (fFK) + added mass of the ship (Ma), and (c) Froude-Krylov force (fFK) + diffraction force (fD) + added mass of the ship (Ma). 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.

Keywords

• international maritime organization
• second-generation intact stability criteria
• surf-riding
• broaching
• added mass
• Froude–Krylove force