Deviation at sea (3)
I believe the answer is:
yaw
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">deviation at sea</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for yaw that I've seen before include "Ship's deviation" , "Deviation (of e.g. ship)" , "(Of ship) twist sideways" , "Temporarily get off course" , "Twisting motion (of ship)" .)