Worried after the soldier climbs aboard the ship (7)
I believe the answer is:
frigate
'ship' is the definition.
(I know that frigate is a type of warship)
'worried after the soldier climbs aboard' is the wordplay.
'worried' indicates anagramming the letters (worry can mean to interfere with or disturb).
'the soldier' becomes 'GI' (term for US soldier).
'climbs' says the letters should be written backwards.
'aboard' means one lot of letters goes inside another.
'gi' reversed gives 'ig'.
'after' with letters rearranged gives 'frate'.
'frate' placed around 'ig' is 'FRIGATE'.
'the' is the link.
(Other definitions for frigate that I've seen before include "Warship - seabird" , "Naval escort vessel" , "Type of warship" , "Warship; -- bird" , "US warship" .)