Obstruction holding up pirate — not much of a catch (7)

'not much of a catch' is the definition.
(a small hook or catch)

'obstruction holding up pirate' is the wordplay.
'obstruction' becomes 'let' (I've seen this in other clues).
'holding up' says to put letters next to each other (some letters go underneath or hold up others).
'pirate' becomes 'hook' (Captain Hook from Peter Pan).
'let' put after 'hook' is 'HOOKLET'.