“…This is due to the effects of, mainly, nonlinear roll damping and nonlinear roll restoring (e.g. Francescutto, 2011, 2013;Bulian et al, 2012;Cardo et al, 1981Cardo et al, , 1982Francescutto and Contento, 1999b;Francescutto and Naito, 2004;Hashimoto et al, 2012;Himeno, 1981;Holden and Fossen, 2012;Kawahara et al, 2009;de Kat and Paulling, 1989;Matusiak, 2007;el Moctar et al, 2012;Neves et al, 2009;Sadat-Hosseini et al, 2010;Sinibaldi and Bulian, 2014;Tzamtzis, 2004). In addition, the sloshing flow inside the tank is also expected to behave nonlinearly as the motions (particularly roll, sway and yaw) increase as a consequence of the increase in the wave forcing.…”