Ship's surgeon finally taken in by mania I'd faked (8)
I believe the answer is:
indiaman
'ship's' is the definition.
'surgeon finally taken in by mania i'd faked' is the wordplay.
'finally' suggests the final letters.
'taken in by' is an insertion indicator.
'faked' indicates an anagram (I've seen 'fake' mean this).
The last letter of 'surgeon' is 'n'.
'mania'+'id'='maniaid'
'maniaid' anagrammed gives 'idiaman'.
'n' inserted inside 'idiaman' is 'INDIAMAN'.
(Other definitions for indiaman that I've seen before include "Former trading ship" , "Large vessel" , "Old trader" .)