 Known colloquially as the Black Ball Line, the PSNC achieved a "virtual monopoly" on cross-sound traffic in the 1930s and competed with the Canadian Pacific Railway's steamships on several routes.Before 1927, when the company was controlled by Joshua Green, the house flag consisted of a design by Mrs. Green, a red star on a white diamond on a blue background.After 1927, when Joshua Green sold his interest to the Peabody family, the Black Ball company flag was transferred over to Puget Sound Navigation Co., and the company became known as the Black Ball Line.