Complex sentence: At one time, in the late 1960s, however, it was one of the most popular classes in Newport Beach, and one race, The Flight of the Kites, had as many as 200 competitors.
Split into simpler sentences: At one time, in the late 1960s, it was one of the most popular classes in Newport Beach. One race, The Flight of the Kites, had as many as 200 competitors.