Lynn Korwatch located on top of Telegraph Hill. George F. Sweeney and Theodore F. Baugh were the two individuals to present the idea of a wooden semaphore on top of Telegraph Hill. A semaphore is a system in which one uses two flags or poles and sends signals in an alphabetic code. Sweeney and Baugh expanded their system by placing a signal station on Point Lobos, which is located 20–30 miles from port in San Francisco. The reasoning behind this was that there was high demand from people wanting to know when the ships were arriving at an earlier time so that
Z flag Z flag The Z flag is one of the international maritime signal flags. In the system of international maritime signal flags, part of the International Code of Signals, the Z flag stands for the letter Z ("Zulu" in the NATO Alphabet) when used in letter-by-letter alphabetic communication. When used alone, it means "I require a tug" or, when used by fishing vessels near fishing grounds, "I am shooting nets". The Z flag when combined with four number flags (The leading two denoting hours, the trailing two denoting minutes) indicates Z Time (also called Zulu Time), a military and maritime term