A 5 year research program to investigate the effect of realistic hull form parameters on the added resistance of a yacht in waves is nearing completion. Model experiments and theoretical predictions were carried out and the results are discussed in this paper. Five hull form parameters have been investigated so far, they are: 1. stern overhang; 2. LCB-LCF separation; 3. prismatic coefficient; 4. displacement length ratio and 5. beam draft ratio.