Set afloat (6)
I believe the answer is:
launch
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">set afloat</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 launch that I've seen before include "Inaugurate" , "Power-driven boat" , "Initiate; a boat" , "Large motorboat" , "Boat - set in motion" .)