AUSTIN, Texas — If Clyde Cain had to guess, he’d say the Louisiana Cajun Navy rescued 8,000 to 10,000 Houstonians during the flooding that followed Hurricane Harvey last year. But, he’s really not sure. “I don’t ever focus on that number … because you don’t have really time to pay attention to that,” said the founder and chief executive officer of the Louisiana Cajun Navy. “The only number that will always matter to me is how many people didn’t get saved. How can we make that number zero?” Cain and his fellow sailors...