Bad rust on the bulkhead can split it! (5)
I believe the answer is:
burst
'split it' is the definition.
I can't tell whether this defines the answer.
'bad rust on the bulkhead' is the wordplay.
'bad' indicates an anagram.
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'the bulkhead' becomes 'b' (head letter of 'bulk').
'rust' anagrammed gives 'urst'.
'urst' placed around 'b' is 'BURST'.
'can' is the link.
Can you help me to learn more?
(Other definitions for burst that I've seen before include "Split asunder" , "Smashed" , "Suddenly break open" , "Exploded" , "Crack" .)