Answer: scends

AnswerCrossword Clue
SCENDSRises on a wave
SCENDSShip's upward movements
scendsto heave in a swell
scendsSCEND, to pitch into the trough of the sea, also SEND
scendsto lurch forward from the motion of a heavy sea
scendsthe forward impulse imparted by the motion of a sea against a vessel
scendsthe heaving motion of a vessel