Johnny Weismuller and Duke Kahanamoku, c. 1925.

Off-Ramp host John Rabe talks with sports historian David Davis about Duke Kahanamoku (1890-1968), one of the founding fathers of modern surfing and swimming, a pioneer in race relations, a beloved figure in Hawaii and a literal lifesaver.
Davis' new book, "Waterman: The Life and Times of Duke Kahanamoku," is the first comprehensive biography of a legend described by another sportswriter as "Babe Ruth and Jack Dempsey combined."
Here's how Davis begins the story:
The precise moment when Duke Paoa Kahanamoku slipped into the shimmering blue waters of the Pacific Ocean is lost to history. Duke himself  recalled only that he was around four years old when his father, so proud of his namesake, the first of the Kahanamoku children to survive infancy, tossed him over the side of a canoe somewhere off Waikiki Beach. "It was save yourself or drown," he said, "so I saved myself."
This was no mere introduction. This was a baptism. Water binds the Hawaiian Islands. It is no exaggeration to say that, in Duke's era, water was the lifeblood of Hawaii and its people. It cleansed their bodies after work and was a transportation source. It was their playground, for surfing, swimming,  and canoe races, and it was a hallowed sanctuary.
On that momentous but unrecorded day, young Duke splashed, flailed, and swallowed water until he discovered his buoyancy and equilibrium, caught his breath, and trusted in the ageless sea that engulfed his body, like his father and uncles and grandfathers before him. Until he felt comfortable enough to stretch his arms beyond his head and pull his hands through the water, his sticklike legs kicking and churning. Until he was moving, self- propelled, his black hair glistening in the sunlight, a little black shadow shimmering in blue liquid. A water bug, soon to be a water boy, soon to be a waterman.
— Excerpt from "Waterman," by David Davis