Official document father left around ship (8)
I believe the answer is:
passport
'official document' is the definition.
(passport is a kind of official document)
'father left around ship' is the wordplay.
'father' becomes 'pa' (pa is a kind of father).
'left' becomes 'port' (left side of a ship - opposite of starboard**).
'around' means one lot of letters goes inside another.
'ship' becomes 'ss'.
'pa'+'port'='paport'
'paport' enclosing 'ss' is 'PASSPORT'.
(Other definitions for passport that I've seen before include "Travel authorisation" , "the key to success?" , "papers" , "It could be important on holiday" , "Authorization to go abroad and return" .)