Throughout the movie the name of the sub Squalus is mispronounced as Squawlus. The correct pronunciation is Skwaylus.
While US Navy crews were not fully integrated in the 1930s, black men did serve, as shown in this film, in the mess.
The third time the man inside the decompression chamber takes the microphone, he doesn't put the switch to "on" before talking.
Jeeps are used as Navy transport vehicles throughout the movie, yet they did not go into production until mid to late 1941, nearly 2 years after the events in this movie are depicted.
Container cranes visible in initial dockside background scenes. Containers were not used in late 1939.