Hull is supported by good English fat (5)
I believe the answer is:
podge
'fat' is the definition.
(I've seen this before)
'hull is supported by good english' is the wordplay.
'hull' becomes 'pod' (I've seen this before).
'is supported by' is a charade indicator (letters next to each other) (letters go below - in down clue).
'good' becomes 'g' (abbreviation).
'english' becomes 'e' (abbreviation).
'pod'+'g'+'e'='PODGE'
(Other definitions for podge that I've seen before include "Fatso" , "One with pounds to spare" , "He needs exercise" , "Fat" .)