Writer Mike Crowe explains:
Through telescopes in these towers, distant ships could be seen approaching a harbor. Tower operators raised signal flags that identified the ship and its distance. This was valuable information for merchants in the days before radio or any other electronics. Ships might be gone months or years with little or no contact with the owners. Signal towers gave them time to organize the effort to reserve wharfage, gather men to unload their ship, prepare for distribution, and in some cases know if they would be first to market.Crowe's two page story of Capt Moody and his tower involves not only marine communications but history, business, construction, meteorology and cartography.