The movie 1941 is actually a Christmas movie. This is about 2 weeks after the Japanese attack on Pearl Harbor Navy base in Hawaii destroys or damages the majority of the Battleships in the US Navy.
Japanese submarines were sinking ships off the coast of California and one did actually shoot artillery at a refinery in central California. The people of Los Angeles are worried about a Japanese attacking the west coast.
This is actually a comedy that should be a Christmas movie for Adults and Mature Teens.
A Los Angeles/Santa Monica California home owner spots a Japanese Submarine offshore and uses an Antiaircraft gun left by the army to try to sink the Submarine.