The Guardian (2006)

Watch The Guardian: Ben Randall is a Coast Guard rescue swimmer. When his crew is killed in an accident and his marriage ends, his commander tells him he wants Randall to go to the US Coast Guard Rescue Swimmer "A" School to train other rescue swimmers. He encounters a guy named Jake who's a little cocky because he was once a swim champion. So Ben puts him through the wringer to see if he can handle it.