Keep Smiling (1925)

The Boy, involved in a maritime disaster as a child, suffers from hydrophobia. He invents a life preserver that automatically inflates when it hits the water, using it to save the life of Rose Ryan, the daughter of a steamship magnate. The Boy takes his invention to Ryan and is mistaken by him for Bordanni, a speedboat racer. In order to present his invention properly, The Boy, totally unprepared and hysterical, is forced to drive Ryan's boat. He is accompanied by a crooked mechanic put on board by Gerald Deane, who is interested in wrecking the boat. More by luck than skill, the boy wins the race, convinces Ryan of the efficacy of the life preserver, and wins the love of Rose.