Below

It's August 1943 and the USS Tiger Shark, operating in the Atlantic ocean right after the biggest U-Boat operation in the war, is asked by a recon Catalina hydroplane to pick up three survivors (a nurse and two patients) of a British hospital ship sunk by German submarine. But for some reason morale in the sub is low and it's going to go even lower as strange accidents start conspiring against the ship's continuing survival. May be something worst than mere bad luck... Maybe even a malediction is at work.

Below is a psychological horror movie with a cast of very familiar faces but not a single star, directed by David Twohy and written by Lucas Sussman and Darren Aronofsky in 2002. The movie did extremely poor numbers at the box office and had mixed, but mostly positive, reviews.

The tropes Below...

 * Abandon Ship: They wish...
 * Anyone Can Die
 * Asshole Victim
 * Awful Truth:
 * Bright Slap
 * Character Tics: Loomis' Yo-Yo playing.
 * Cruel and Unusual Death
 * Did Not Do the Research: British merchant ships wouldn't fly the Union Jack, submarines were segregated during WWII and maximum periscope depth was 62 feet, for example.
 * Dissonant Serenity
 * Freak Out
 * Geek: Of the kind that read Amazing Stories and Weird Tales.
 * Ghostly Goals
 * Jump Scare: One of the complaints about the movie was that it played too much by the numbers, both as a sub and a horror story.
 * Locked Out of the Loop: Most of the crew ignore the Awful Truth.
 * The Scottish Play
 * Manta Scare
 * Maybe Magic, Maybe Mundane: A saboteur? Plain bad luck? Ocean Madness? A ghost?
 * Mirror Scare
 * Nautical Folklore: A woman aboard... tsk tsk.
 * Naval Weapons: Including the least known and least subtle anti-sub weapon of the war, the hooks.
 * Ocean Madness
 * Peek a Boo Corpse
 * Shirtless Scene: And even more.
 * Silent Running Mode: Yep, this movie has all the sub tropes.
 * Star Trek Shake: Averted. The crew is tossed around like ragdolls, even against the upper deck.
 * Sub Story: Of course.
 * Unusual Euphemism: Some of the Forties slang is pretty colourful: "skirt" and "bleeder" for a woman, for example.
 * World War II