Yearns to get cool boat (8)
I believe the answer is:
longship
'boat' is the definition.
(I've seen this before)
'yearns to get cool' is the wordplay.
'yearns' becomes 'long s' ('long' can be a synonym of 'yearn').
'to get' means one lot of letters go next to another.
'cool' becomes 'hip' (hip can mean cool or fashionable).
'longs'+'hip'='LONGSHIP'
(Other definitions for longship that I've seen before include "Viking vessel" , "Viking boat" , "Viking craft" .)