Screwpiles: The Forgotten Lighthouses

A considerable amount of time was needed to produce accurate charts. To alleviate demand, Superintendent Bache adopted the practice of issuing preliminary survey results. Those charts showed accurate shorelines, bays, and harbors, but left the less important features to later surveys. 14 Sketch C of the Chesapeake Bay includes surveys from 1843 to 1857.

The U.S. Coast and Geodetic Survey map of 1899 shows increasing details of cities and towns, shorelines, soundings, channels, and dredging depths. Aids to navigation are shown and lighthouse specifications are listed.

Craney Island still exhibits its original shore outline.

The approach to the Elizabeth River is dredged to 28 feet.

An interesting note is listed on the chart:

Time Ball

A Time Ball is dropped from the Hygeia Hotel, Fort Monroe at Noon 75th Meridian, 5h, 00m,00s Greenwich Meant Time. A time ball was used to allow mariners to set their chronometers daily to Greenwich Mean Time. This was a navigational feature noted on charts of major harbors worldwide from the 1830s to the 1920s.

Time ball, Greenwich, England Wikipedia

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