My salesman gave me an invoice(?) of some sort with vehicle VIN, description & details the day I committed to buy...and it had "Vessel Name" on it. I was able to track it online by the ship's name. Turned out it had docked at an NJ port a day earlier, and already leaving toward the Panama Canal. From that point it took 10 days to arrive at the dealership; paperwork and plates all ready to go. Just for fun, I tracked the vessel again, and it was past the Panama Canal and heading for Japan.
I'm assuming if I had this info, you can get it from your salesman, too? (unless it hasn't been boarded on a ship yet, which can be an excuse)