Initially admiral’s found turning towards the stern (3)
I believe the answer is:
'towards the stern' is the definition.
(I've seen this before)
'initially admiral's found turning' is the wordplay.
'initially' says to take the initial letters.
The first letters of 'admirals found turning' is 'AFT'.
(Other definitions for aft that I've seen before include "Toward the stern of a boat" , "Farther back on board" , "Towards the back on board" , "At the back of a ship" , "Towards rear (of ship)" .)