Ship, with hesitation, has problems (4)
I believe the answer is:
sums
'problems' is the definition.
(arithmetic problems)
'ship with hesitation' is the wordplay.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'with' indicates putting letters inside.
'hesitation' becomes 'um' (um is said in hesitation).
'ss' placed around 'um' is 'SUMS'.
'has' is the link.
(Other definitions for sums that I've seen before include "Amounts of money" , "Exercises in arithmetic" , "Quantities obtained by addition" , "Calculations" .)