Seaman, each morning, makes it directly across the middle of the ship (5)
I believe the answer is:
abeam
'makes it directly across the middle of the ship' is the definition.
I can't tell whether this defines the answer.
'seaman each morning' is the wordplay.
'seaman' becomes 'ab' (short for able seaman).
'each' becomes 'e' (this might be a standard abbreviation which I don't know about).
'morning' becomes 'am'.
'ab'+'e'+'am'='ABEAM'
Can you help me to learn more?
(Other definitions for abeam that I've seen before include "across the deck" , "Set across" , "at right angles to a ship's keel" , "At right angles to the side of a ship" , "across width of ship" .)