A huge order for ships (5)

I believe the answer is:

avast

'order for ships' is the definition.
(nautical term meaning 'stop')

'a huge' is the wordplay.
'huge' becomes 'vast' (I've seen this before).
'a'+'vast'='AVAST'

(Other definitions for avast that I've seen before include "order for tar" , "Hold fast! (naut.)" , "shout stopping the ship" , "Stop! (naut.)" , "Stop at sea" .)

I've seen this clue in The Times.

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