Ace management team on a ship (6)
I believe the answer is:
aboard
'on a ship' is the definition.
(I've seen this before)
'ace management team' is the wordplay.
'ace' becomes 'a' (abbreviation).
'management team' becomes 'board' (the board of an organisation or business).
'a'+'board'='ABOARD'
(Other definitions for aboard that I've seen before include "On (a ship/plane)" , "Alongside" , "in a car" , "On an aircraft" , "on a plane, perhaps" .)