Twin-hulled craft (9)
I believe the answer is:
catamaran
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">twin-hulled craft</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for catamaran that I've seen before include "Two-hulled boat" , "Boat with twin, parallel hulls" , "raft of logs" , "Boat with two hulls" , "One vessel" .)