Pester hearty on tour of ship (6)
I believe the answer is:
hassle
'pester' is the definition.
(I've seen this before)
'hearty on tour of ship' is the wordplay.
'hearty' becomes 'hale' (I've seen this in another clue).
'on tour of' indicates putting letters inside (some letters tour around others).
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'hale' going around 'ss' is 'HASSLE'.
(Other definitions for hassle that I've seen before include "problem" , "An informal quarrel or upset" , "Struggle" , "Bother, fuss" , "(Cause) stressful annoyance (to)" .)