Gloom made Danes travel by ship (7)
I believe the answer is:
sadness
'gloom' is the definition.
(I've seen this in another clue)
'danes travel by ship' is the wordplay.
'travel' is an anagram indicator (I've seen 'travelling' mean this).
'by' means one lot of letters go next to another.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'danes' is an anagram of 'sadne'.
'sadne'+'ss'='SADNESS'
'made' acts as a link.
(Other definitions for sadness that I've seen before include "regret" , "gravity" , "Dolour" , "Gloom" , "blues" .)