Optimization of ship's bow form for the added resistance in waves

For large ships, the likely sea states the ship may encounter in her lifecycle are in the region of short waves, where the diffraction component of the added resistance is predominant. In this paper, an optimization of the bow form of the standard ITTC KVLCC2 tanker was performed in terms of the added resistance, calm water resistance, total resistance and Energy Efficiency Design Index. The added resistance was estimated using semi-empirical formulas developed by the Ship Design Laboratory of NTUA. A parametric geometry model of ship's bow region and optimization process were formulated within the CAESES/Friendship-Framework. The conducted multi-objective optimization procedure showed that the added resistance is strongly correlated to ship's waterplane area coefficient, moderately to ship's stem profile and weakly to the bow's flare angle. The optimized bow design resembles closely the LEADGE bow hull concept, which is becoming very popular in recent full type ship newbuildings.