{v. phr.} Said of a person, a vehicle, or a memorable thing who/which has started leaving or moving, both as a statement of fact (declarative assertion) or as a command (imperative). * /When the boat hit the water in the formal launching ceremony, they cried out simultaneously, "Off she goes!"/
OFF (ONE/HE/SHE/IT) GOES!
Meaning of OFF (ONE/HE/SHE/IT) GOES! in English
Dictionary of English idioms . Словарь английских идиом. 2012