**Emre Kahramano ˘glu, Ferdi Çakıcı \* and Ali Do ˘grul**

Department of Naval Architecture and Marine Engineering, Yıldız Technical University, 34349 Istanbul, Turkey; emrek@yildiz.edu.tr (E.K.); adogrul@yildiz.edu.tr (A.D.)

**\*** Correspondence: fcakici@yildiz.edu.tr; Tel.: +90-212-383-2848

Received: 30 May 2020; Accepted: 19 June 2020; Published: 20 June 2020

**Abstract:** The evaluation of the hydrodynamic performance of planing vessels has always been one of the most attractive study fields in the maritime agenda. Resistance and self-propulsion studies have been performed using experimental and numerical methods by researchers for a long time. As opposed to this, the seakeeping performance of planing hulls is assessed with 2D approximation methods, but limitedly, while the experimental campaign is not cost-effective for several reasons. With this motivation, pitch and heave transfer functions and accelerations were obtained for a monohedral hull and a warped hull using a state of art commercial Reynolds-averaged Navier–Stokes (RANS) solver, in this study. Moreover, 2-DOF (degree of freedom) dynamic fluid–body interaction (DFBI) equations were solved in a coupled manner with an overset mesh algorithm, to find the instantaneous motion of the body. After verification, obtained numerical results at three different Froude numbers and a sufficiently large wave frequency range were compared with the experiments. The results showed that the employed RANS method offers a very accurate prediction of vertical motions and accelerations for planing hulls.

**Keywords:** CFD; overset mesh; planing hull; seakeeping; vertical motions
