Of course what holds the movie together is the ambiquous relationship between Chavez (Anthony Quinn) and Emily (Deborah Baxter). The musical score and their eye contact when Chavez first climbs aboard (after the violent clunk of the grappling hook) emphasizes some sort of immediate emotional understanding between them. Zac (James Coburn) realizes this -- he's not sure what it is, but is aware it could be dangerous. I believe the actors and director manage this perfectly. James Coburn provides just the right amount of relief from a situation that could become too intense, and Emily herself is unsure what it's really about but also understands its potential danger. This is shown when Chavez and Emily wrestle on the deck (this was too much for one audience in a theatre in which I saw the movie in 1966 -- they became very uncomfortable), and Emily then beats Chavez on the back, telling him that he is an evil pirate (after telling another of the children shortly beforehand that the crew are the 'pilot' and not 'pirates') and that he will go to hell. Chavez appears completely mortified. To me, Quinn plays Chavez as a pirate going through a 'mid-life crisis'. Perhaps he is realizing the anguished loss of not having a family and children, and of having lived the life of a pirate who stays at bordellos between succesful raids and now has nothing much to look forward to. Now he has something like a 'substitute family' to whom he can display his long-buried tender feelings and the children respond with affection for him. Zac realizes that it has become more important to Chavez to provide proper care for the injured Emily than to risk her missing this because of an attack on an apparently rich Dutch Trader. The crew then mutiny. Emily has adopted views of how a pirate should behave when she tells Chavez that he should be attacking the other ship with the crew because, "You're the Captain!" Of course, later at the trial, Emily knows she killed the Dutch Captain, but sacrifices Chavez rather than admit her guilt. Chavez understands and more or less indicates to her not to feel badly about what she is doing -- he is no longer very interested in living anyway. It is this portrayal of Chavez that distinguishes him from the equivalent character (Jonson) in the book, and makes the Quinn character so much more sympathetic. I think it shows Quinn's greatness as an actor that he is able to bring this off, and the amazing ability of the young Deborah Baxter who is able to counter-play the delicate balance in their relationship.
david, you nailed it...that review absolutely goes to the heart of this wonderful movie. Kudoes!