Wonder what that looks like on infrared. That might be what they're hiding from. Ex: drones. The optical camera would still pick it up though.
The vodka probably helps their systems cope with whatever is in that smoke. Heck it probably *IS* vodka that they're just evaporating. The ship itself probably actually runs off Vodka too!
Unfortunately, vodka doesnt stronk carbon monoxide, which is what one poor sailor found out when he died in 2009 while working on that ship.
So much for EMCON on that thing, shouldn't be too hard to find it anywhere, save for a hurricane.