By the latter part of the 18th century, the port of Baltimore was a hubbub of piers and wharves spanning much of Fells Point and the Inner Harbor. Convoys of ships, including the fleet Baltimore Clippers, sailed up the Patapsco River only to arrive in the harbor without advance notice to workers and businessmen. Logjams and costly delays were the norm of the day.

In 1790, some local entrepreneurs devised an advanced notification system called the “Baltimore Telegraph.” Spotters would peer through a powerful telescope from a lookout perch atop Federal Hill to identify owners? vessels or colors. Signal flags could then be displayed from a tower, providing several hours? advanced notice to waterfront workers.