The three survivors of the shipwreck were being driven mad by hunger.
The Irishman, an expert navigator, told the others that if they could row the lifeboat for three more days they could make landfall.
The Pole, the ship's doctor, said that they could not possibly last that long, that there was only one solution to the problem and that one of them would have to sacrifice themselves for the good of the others.
The Englishman, the captain, said that he quite understood and that he would volunteer as he should have gone down with the ship anyway.
After saying an emotional farewell to his crewmen, the captain jumped overboard and sank without trace.