sentences:  During the mid sixties Columbia produced a few motor yachts.By the late 1960s,the company was the world's largest fiberglass sailboat manufacturer, with manufacturing plants throughout the world.Valdes and Threinen sold the company to Whittaker (listed on the NYSE), but Valdes continued as president of the subsidiary Columbia Yacht Corporation, and helped to develop Whittaker Marine Group, which ultimately included Bertram Yachts, Trojan Yachts, Riva, Desco Marine, Kettenburg, Balboa Marine, and Coronado Yachts.