Old sailor travels north to collect a daughter
I believe the answer is:
seadog
'old sailor' is the definition.
(I've seen this before)
'travels north to collect a daughter' is the wordplay.
'travels' becomes 'goes' ('go' can be a synonym of 'travel').
'north' says the letters should be written in reverse (in a down clue, letters go up or 'northward').
'to collect' is an insertion indicator.
'daughter' becomes 'd' (genealogical abbreviation).
'goes' written backwards gives 'seog'.
'a'+'d'='ad'
'seog' enclosing 'ad' is 'SEADOG'.
(Other definitions for seadog that I've seen before include "Mate, perhaps" , "Rating" .)