On board, beaten seaman died (5)
I believe the answer is:
mated
'on board beaten' is the definition.
I can't tell whether this defines the answer.
'seaman died' is the wordplay.
'seaman' becomes 'mate' (mate is a kind of seaman).
'died' becomes 'd' (abbreviation next to the year of someone's death).
'mate'+'d'='MATED'
Can you help me to learn more?
(Other definitions for mated that I've seen before include "Defeated in game" , "Joined, connected" , "had sex" , "given match" .)