four o'clock
`` Little Mack '' adjusted the receivers and stood listening to the revolving propellers of the craft that approached and passed overhead . For a moment he debated the idea of releasing a torpedo that might be noticed by the crew of the unknown vessel . But such a plan was not feasible , for the ship would think only of being attacked and would stand ready to repel an enemy rather than look for a submarine in distress . Furthermore , such an expedient was out of the question ; for , gazing at his watch , he found that it was only four o'clock and hardly light enough for a torpedo to be seen unless it passed very close to the oncoming ship . `` There is one thing we might do , '' spoke up Jack Hammond . `` Lieutenant , I have a plan to suggest . We seem to be in a desperate situation that demands some prompt action .