In this talk we will describe the derivation of mathematical and numerical models for the simulation of high performance rowing boats. Rowing boats are a complex dynamical system strongly affected by the rowers action and movements. Indeed a rowing boat hardly moves with constant speed, but it is instead subject to a complex system of secondary movements: horizontal and vertical accelerations as well as pitching are the main ones. These in turn generate gravity waves which dissipates part of the rowers power. A numerical model may help a boat manufacturer to foresee the behaviour of new a boat design, and a trainer to better understand how crew composition and rowing style may affect performance. We present the results of several years of collaboration with an important rowing boat manufacturer for the development of a complete mathematical model of the boat dynamics and of its interaction with the free surface flow.