Design boats (5)
I believe the answer is:
craft
This clue is a double definition.
'design' is the first definition.
(thesaurus)
'boats' is the second definition.
(I've seen this before)
(Other definitions for craft that I've seen before include "Vehicle for water or air" , "Workmanship" , "packet!" , "Occupation in which skill is needed" , "SECOND PART OF 23" .)