The entire movie is interspersed with real WW2 footage and promotional films to help men enlist. It's a little strange, and to be honest, I could have done without the constant cuts, but if you can get used to it early on, that will help you. Screenwriters Phillip Rock and Hal Dresner must have wanted the entire film to feel satirical, but I think it would have been even better without the stock footage. Now to the plot: Alan Alda, Mickey Rooney, Jack Carter, and Manu Tupou are shipwrecked on a deserted island during WW2. They come across an abandoned, wrecked ship, but quickly find that it's not quite abandoned! David Niven, the ship's captain, is still aboard, drinking, making whimsical remarks no one seems to understand, and far from anxious to help with the war effort. But together, and with a random appearance by Faye Dunaway, they patch up the boat and try to help fight the Japanese.
Without David Niven's character, the movie would be terrible. And without David Niven cast in the role, it would have devolved into a silly 70s comedy with no class or charm. Everything funny and lovely in the film is due to The Niv's splendid comic timing and suaveness. After watching this film, I dare you not to wish he'd been cast in The Ghost and Mrs. Muir. He's infinitely more likable than Rex Harrison. For that matter, why wasn't he cast in My Fair Lady? Well, I guess that's an issue for another time. For now, if you'd like a silly war comedy, give The Extraordinary Seamen a try.