Three-hulled boat (8)
I believe the answer is:
trimaran
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">three-hulled 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 trimaran that I've seen before include "Sailing boat with 3 hulls" , "Sailing boat with three hulls" , "Three-hulled yacht" , "Three-hulled vessel" , "type of boat" .)