Prototype's trendy - for an army vessel (9)
I believe the answer is:
troopship
'an army vessel' is the definition.
(I've seen this before)
'prototype's trendy' is the wordplay.
'prototype's' becomes 'troops' (I can't explain this - if you can you should believe this answer much more).
'trendy' becomes 'hip' (I've seen this in another clue).
'troops'+'hip'='TROOPSHIP'
'for' is the link.
Can you help me to learn more?
(Other definitions for troopship that I've seen before include "boat" , "Army vessel" , "Military transport vessel" , "As carrier" .)