Caleb Brewster used experience in whaling and coastal navigation to serve the American cause during the Revolution. He joined the Continental forces and became a lieutenant of artillery, but much of his distinctive work took place on Long Island Sound. Commanding small crews in whaleboats, he crossed between British-occupied Long Island and the Connecticut shore, gathering information and carrying out raids and other military errands.

From 1778 Brewster provided the waterborne link in the intelligence network organized by Benjamin Tallmadge, later known as the Culper Ring. Reports collected by Abraham Woodhull and Robert Townsend passed through a chain of couriers before Brewster brought them across the Sound for transmission to Washington. He also reported directly on shipping and troop movements. Unlike agents whose effectiveness depended on concealed identities, he combined intelligence duties with conspicuous armed activity against British patrols and coastal positions.

After the war Brewster settled at Black Rock, Connecticut, where he worked as a blacksmith and farmer. In 1793 he entered the Revenue Cutter Service, enforcing customs laws along the same coast he knew from wartime. With an interruption during the Adams administration, he continued in revenue service and commanded the cutter Active during the War of 1812 before retiring in 1816. He died in 1827. Anna Strong’s clothesline signals are later tradition, not secure evidence of his operations.