Sets a boat afloat (8)
I believe the answer is:
launches
'sets a boat afloat' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for launches that I've seen before include "Sets in motion, a ship say" , "Sets afloat - motor boats" , "Sets in motion,a ship say" , "Sets a boat afloat" , "Motorboats" .)