early, land-based Chesapeake Bay lighthouses cost as little as $5,000, while
caisson lights, built later and for open-water conditions, cost as much as $100,000
or more. Confronting severe erosion or weather-related assaults such as floating
ice, lights in some locations were repeatedly damaged or destroyed and rebuilt.
A succession of five different installations, including two towers, two lightships,
and a screwpile lighthouse, were placed to warn mariners off the hazardous shoal
at Smith Point, on the Virginia side of the Potomac River. Today a sturdy caisson
light marks the spot.
Donohoo, of Havre de Grace, has been called the “master lighthouse builder
of the Chesapeake.” In all, Donohoo built 12 Chesapeake Bay lights, including
those at Thomas
Battery, and Concord
Point. Seven Donohoo structures have survived to the present.
A Light on the Roof:
in which the lanterns were integrated into the keeper’s quarters are known
as “integral” lighthouses. Because the structures were relatively
inexpensive to build, they were a common option in the early years of U.S. navigational
aids. The oldest one in the nation is the Point
Lookout light at the entrance to the Potomac River.
A Low Paying Job:
keepers generally earned paltry wages. In 1806, the keeper of the Cape
Henry light was paid only about $16 a month for his services. By the 1890s,
the maximum wage had risen to about $50 per month. In the early years of lightships,
all of $73 a year—twenty cents a day—was allotted for each crew
The Fresnel Lens:
electricity, Bay lighthouse lanterns glowed with the light of oil lamps magnified
by highly polished lenses. Eventually all featured lenses equipped with a carefully
crafted prism and powerful magnifier invented by the French physicist Augustin
Fresnel. Fresnel’s revolutionary lenses came in seven different sizes,
or “orders.” A first-order Fresnel lens, the largest, was a whopping
7 feet 10 inches high and just over 6 feet in diameter. Many Bay beacons were
fitted with fourth or fifth order lenses—the latter only about 20 inches
tall and roughly 14 inches in diameter. Even these smaller Fresnel lenses were
powerful enough to cast a beam for miles across Bay waters.
20th Century Lights:
five of the 74 Chesapeake Bay lights were commissioned in the twentieth century.
The last to be built, the Chesapeake
Light Tower 14.5 miles east of the Bay’s entrance (built in the “Texas
tower” style reminiscent of oil-drilling platforms), was constructed in
1964. Until the tower became fully automated, personnel were transported to
the tower by helicopter.
Who’s in Charge?
Beginning in colonial times, responsibility for lighthouses and other navigational
aids in U.S. waters has resided with a series of entities and agencies:
Pre-1789 - Individual colonial governments
1789-1820 - U.S. Government
1820-1852 - Fifth Auditor of the Treasury
1852-1910 - U.S. Light-House Board
1910-1939 - Bureau of Lighthouses/U.S. Lighthouse Service
1939 - present - U.S. Coast Guard
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