There are so many to choose from for this theme. War as a subset yields numerous excellent choices, and the non-fiction selection is amazing. And of course Hollywood just loves putting people in peril on, in and under the water, so lets see what we can sea.
Poseidon Adventure- the newer Kurt Russell from 2006---corny,over-the-top disaster movie, but I always find that no matter what the movie, Kurt delivers a watchable performance.
The Perfect Storm--- Mark Wahlberg, George Clooney, and some other guys. Not as good as they hyped it, but still worth a watch.
Night To Remember---before the mega hit, king-of-the-world, billion dollar, multi-award winning, James Cameron extravaganza,Titanic, there was this quieter, more realistic movie of the doomed ship. We also have the documentary Titanic: Born in Belfast.
LIfeboat---ahhh---Hitchcock. Ask yourself what you would have done?
And of course Mutiny on the Bounty- any number of versions.
This was one of my very first recommendations back when we started the blog. It bears mentioning again- the wonderful Das Boot. This will make you think twice about signing on as crew in a submarine (were you even thinking of doing it once?).
Speaking of submarines, check out Harrison Ford in K19, the Widow Maker. This is the story of Russia's first nuclear sub and a whole lot of radioactive trouble.
Sinbad- we have the Dreamworks animated and the wonderful 1958 version. Long before all the CGI and green screen technology things were done the old fashioned way- stop-motion animation. And no one did it better than Ray Harryhausen. Yes, kids might think it looks a little cheesy these days, but just think of the craftsmanship that went into these scenes.
The Abyss- before Cameron turned his hand to Titanic, he offered us this solid undersea action/thriller/sci-fi movie. Bit of trivia-the always innovative Cameron actually invented the diving masks used in the film. He found he wasn't getting enough of the actor's faces with the traditional style so he designed and patented these masks, which are now pretty much standard fare.
Old Man and the Sea- Spencer Tracy portraying Hemingway's Cuban fisherman in this classic tale of perseverance.
African Queen- if you have never seen this Bogie and Hepburn classic, treat yourself. This just works on every level-drama, adventure, romance, action.
Deep Water-documentary about a doomed 1968 round the world yacht race
Sinking of the Lusitania--- an excellent offering from PBS about the sinking of said ship off the coast of Ireland in 1915
Shallow Seas--- from the excellent Planet Earth series. Watch this one- watch them all.
Of course what list would be complete without The Little Mermaid, Finding Nemo and Sponge Bob Square Pants.