Back of a boat (5)
I believe the answer is:
stern
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">back of a boat</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stern that I've seen before include "Austere rear part of a ship?" , "Rear end" , "Rear of a vessel" , "Unyielding part of the ship" , "Tail of a beagle" .)