I didn't see the movie, but chances are Hollywierd fouled up the language/translations as they usually do.
You guys may be too young to remember the movie "Das Boot". "Das Boot" in German to English means "the boat" in this case "Das -U-Boot" or the "Unterwasser boot" which we call an "underwater boat" or "submarine".
What you guys are looking for is called a "bierstiefel".
The beer served during the O'fest is called a "Marzen" or March beer because that's when it's brewed.
You can get a Hefe, but it's not available in all the tents. I used to live 40 miles from Munich and have been to the "Wiez'n" (as it's called by the locals) over a dozen times...1975, 1976, 1977, 1978, 1999, 2000, 2001, 2002, 2003...