Why did Quint break the radio?

'Certifiable'.

He struck me as a macho guy, he was not calling ANYBODY for help. He had a fine boat, a trusty harpoon and also he was Robert Shaw so he was very likely drunk most of the time.

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He wasn't going to allow Hooper to call for help. His pride wouldn't allow it. This is HIS trophy.

Remember the story he recounted to Brody & Hooper about his wartime experiences? This was the best part of the movie. Well I think that it has to do with that. It’s a pretty horrifying story, the sinking of the Indianapolis and all those men thrown into the ocean full of sharks, out of thousands, only a few hundred wound up surviving. Remember Quint saying that the mission he was on was “So secret, that nobody knew to even look for us until a week later.” That’s gotta suck big time man, you KNEW that being in their situation you were screwed BIG TIME.

This is why I think he snapped and bashed the radio. Thing is I think Quint wasn’t sure he was going to make it but due to his experiences in the war, he had a score to settle, win or lose, live or die, at all costs he was going to confront this particular demon from his past at everyone’s expense which is why he did what he did. Did he mean Brody & Hooper any harm? No, but he couldn’t help himself. He found he had nothing else to live for but this showdown with the great white, that fate had presented to him now at the end of his life so he was going down with the ship as they say.

This is what I think anyway. I’m sure many of you have other opinions.

It's a Spielberg movie - since when do his characters act calmly and rationally?

Also, it's a hint for the viewer that Quint won't survive the movie.

Quint was obsessed at that point, kind of like Captain Ahab from Moby Dick.

He was going to get that shark or die trying.

To claim his 10 grand