Science and Education Publishing International Journal of Physics 2333-4576 4 6 2017 1 9 Control of Roll Motion of Fishing Vessel by Fin-Stabilizer Using PID Controller 181 186 EN Hassan Ghassemi Department of Maritime Engineering, Amirkabir University of Technology, 424 Hafez Ave, Tehran, Iran Hamid Malekizade Arash Ashrafi IJP2016465 10.12691/ijp-4-6-5 2016 8 29 2016 11 16 2017 1 7 The aim of this study is to diminish the roll motion of the fishing vessel using fin-roll stabilizer. In this regard, lift coefficient of the fin and the hydrodynamic coefficients of the roll equation are calculated by empirical formulas. In effect, constrained LQR (Linear Quadratic Regulator) controller is designed and used to control the roll motion in the presence of operational constraints of fin's actuator. In order to boost the validity of our results, the performance of this controller is compared with a conventional PID (Proportional-Integral-Derivative) controller. Finally, simulation results indicate the significant amount of reduction in roll amplitude.