War movie from the 70's probably

So I hope you can help me. I saw this movie when I was small.

As I remember the settings, it is about a soldier who has an accident on the sea, probably somewhere close to Asia. He lives on an island where a woman helps him to heal. The end of the movie is that he goes to some fight on the sea and he dies because the boat drags him down into the water.

I watched this movie about a month ago on DVD. I am certain the film you are looking for is the 1971 film Murphy’s War, directed by the brilliant Peter Yates. Peter O’Toole plays Murphy, an Irish seaman, who is one of only two men to survive a U-boat attack on a South American river in the final days of WWII. Natives find Murphy and bring him to a woman doctor who nurses him back to health. But Murphy is consumed with the need for vengeance. He won’t listen to the doctor’s plea to let it rest. He repairs and old plane, improvises some bombs, and sets out to find and destroy the German U-boat. He comes close to succeeding, and the Germans stage a counterattack on the village that took in Murphy, killing the second survivor and several villagers. This makes Murphy even more eager for revenge.

The film has a tragic conclusion just as you described. News of Germany’s surrender reaches Murphy and the German U-boat, but Murphy continues his mission to destroy the U-boat and its men even as they celebrate the end of conflict. Murphy stages a final attack on the sub using an old mining rig. The submarine, in an effort to escape Murphy, gets trapped on a sand barge while submerged and all the German’s die. Murphy’s own rig sinks, with him tangled in its lines. The closing shot is Murphy sinking into the sea. The war has ended, yet everyone dies because of Murphy’s lust for vengeance.

You really are an expert!! Thanks!