Unable to get enough working at sea in it (9)
I believe the answer is:
insatiate
'unable to get enough' is the definition.
(I've seen this before)
'working at sea in it' is the wordplay.
'working' is an anagram indicator.
'at'+'sea'+'in'+'it'='atseainit'
'atseainit' with letters rearranged gives 'INSATIATE'.
(Other definitions for insatiate that I've seen before include "Unable to get enough" , "wanting more" , "Not fully satisfied" .)