I'll echo JalekZem's question, not sure what you mean by long or short start.
Personally I'm fine with what ever start suits the game. In PbP games, more than face-to-face games, starting with some sort of action or "event" (not necessarily combat) tends to get the game rolling and everybody involved fast.
And I will third the question.what do you mean by "Long Start" and "Short Start"?
Long start: The group two extra weeks to roleplay and do stuff on the ship.
Short Start: Group gets into an encounter.












