Gravelly Shoal Light

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Gravelly Shoal Light
Gravellyshoal.JPG
Undated USCG photo
Gravelly Shoal Light is located in Michigan
Gravelly Shoal Light
Location Saginaw Bay, Michigan
Coordinates 44°1′6″N 83°32′14″W / 44.01833°N 83.53722°W / 44.01833; -83.53722Coordinates: 44°1′6″N 83°32′14″W / 44.01833°N 83.53722°W / 44.01833; -83.53722
Year first constructed 1939
Year first lit 1939
Foundation 50-foot (15 m) diameter concrete pier[1]
Construction Steel-sided tower
Tower shape Art Deco
Markings / pattern white, gray scaffold atop
Height Tower - 65 feet (20 m)[2]
Focal height Focal plane - 75 feet (23 m)[3]
Current lens 14.8-inch (375 mm) lens[4]
Intensity 15,000 candela[5]
Range 9.6 nautical miles; 18 kilometres (11 mi)
Characteristic red flash every 6 seconds[6]
Fog signal Every 30 seconds, operates year round.[4]

Radio beacon signal transmitted at 296 kilocycles, and emitted a group of 0.5 -second dashes for 15.5 seconds, followed by 14.5 seconds of silence.[5]

ARLHS number USA-340[7][8]
USCG number 7-10540

Gravelly Shoals Light is an automated lighthouse that is an active aid to navigation on the shallow shoals extending southeast from Point Lookout[9] on the western side of Saginaw Bay. The light is situated about 2.7 miles (4.3 km) offshore and was built to help guide boats through the deeper water between the southeast end of Gravelly Shoals and Charity Island. Architecturally this is considered to be Art Deco style.[10]

History[edit]

As part of President Roosevelt's New Deal and its program to "Put America Back to Work" the new light tower was put up for bid, and built in 1939.[11] It replaced an earlier gas-lit buoy. It also displaced the Charity Island Light,[12] which was constructed in 1857, and operated until 1930.[5]

Contemporary unmanned lights in the Art Deco style is the Indiana Harbor East Breakwater Light and its twin, the better known Port Washington Breakwater Light in Wisconsin.[13][14]

When built according to its original specifications, the contractor warned that the foundation was inadequate to withstand the buildup of ice, and put in a bid for a contract modification. However, at the time jurisdiction over the light had just been transferred to the Coast Guard from the United States Lighthouse Service, and they chose to disregard the warning, and to accept the light as built. This resulted in substantial additional expense in due course, as the light had to be retrofitted.[5]

This light is designed as an autonomous automated electrified station. It is under the control and maintenance of Coast Guard Station in Tawas City, Michigan. Ordinarily it displays a 15,000 candela 14.8 inches (375 mm) light powered by a 120 volt electric lamp. Power is supplied through a submarine cable, which crosses the shoal from Point Lookout. The 75-foot (23 m) focal plane makes its flash (1-second every 5 seconds) visible for 14 nautical miles; 26 kilometres (16 mi). It is supplemented by a standby 110 candela acetylene light with a half second flash every three seconds—which activates automatically if there is a power failure. In foggy weather, mariners are warned by twin compressed-air two-tone #3 diaphones, which operate on a 30-second cycle (3-second blast followed by 27 seconds of silence).[5]

The National Data Buoy Center lists the Site Elevation as 588 feet (179.2 m) above sea level; an automatic readout for wind, waves and weather is operated there.[15]

The National Weather Service operates an automated weather observing station at the lighthouse.

An added large steel tower atop the light is a radio beacon. The 1953 Coast Guard Light List indicates that the signal transmitted at 296 kilocycles, send forth a group of half-second dashes for 15.5 seconds, followed by 14½ seconds of silence. As of 2001, both the light and radio beacon served as active navigational aids.[5]

Although it never had a resident lighthouse keeper, this light is a recognized 'significant light" by the National Park Service National Maritime Initiative.[16]

Getting there[edit]

A good passing view of the light can be had while riding the ferry from Au Gres to Charity Island, which is 10 miles (16 km) to the east in the middle of Saginaw Bay.[17] Tours of Charity Island (and even dinner cruises) are available, which can include the privately owned, rebuilt Charity Island Light lightkeeper's house. They are available from Charity Island Transport, Inc. in Au Gres, Michigan on the mainland, south of Tawas.[18]

It is also possible to take a telephoto shot from shore.

US 23.svg US 23 north from Au Gres, 4.8 miles (7.7 km) to Point Lookout Road. Turn right to its end; turn left onto Michigan Ave. Through a break in the houses one can see Saginaw Bay and the light.[19]

See also[edit]

Notes[edit]

  1. ^ Detroit News , Interactive map on Michigan lighthouses.
  2. ^ Pepper, Terry. "Database of Tower Heights". Seeing the Light. terrypepper.com. 
  3. ^ Pepper, Terry. "Database of Focal Heights". Seeing the Light. terrypepper.com. 
  4. ^ a b Rowlett, Russ. "Lighthouses of the United States: Michigan's Eastern Lower Peninsula". The Lighthouse Directory. University of North Carolina at Chapel Hill. 
  5. ^ a b c d e f Terry Pepper, Seeing the Light, Gravelly Shoal Light.
  6. ^ Light List, Volume VII, Great Lakes (PDF). Light List. United States Coast Guard. 
  7. ^ Amateur Radio Lighthouse Society, Gravelly Shoal (Lake Huron)Light ARLHS USA-340
  8. ^ Amateur Radio Lighthouse Society, World List of Lights (WLOL).
  9. ^ Wobser, Dave, Gravelly Shoal Light, at boatnerd.com.
  10. ^ Lighthouse Depot, Gravelly Shoal light.[dead link]
  11. ^ Lighthouse Central, Gravelly Shoal Light Photographs, History and Directions, The Ultimate Guide to East Michigan Lighthouses by Jerry Roach[dead link] (Publisher: Bugs Publishing LLC - July 2006). ISBN 0-9747977-1-5; ISBN 978-0-9747977-1-7.
  12. ^ Bostwick, Violet M., Charity Island Light, Boatnerd.com.[dead link]
  13. ^ "Historic Light Station Information and Photography: Indiana". United States Coast Guard Historian's Office. Retrieved 2008-11-24.  Note that the document has a picture of the Indiana Harbor East Breakwater Light under "Indiana Harbor Light", and that it has the correct history and wrong picture under "Indiana Harbor East Breakwater Light"
  14. ^ Rowlett, Russ. "Lighthouses of the United States: Indiana". The Lighthouse Directory. University of North Carolina at Chapel Hill. 
  15. ^ National Buoy Data Center with automatic readout of wind, waves and weather for Gravelly Shoal Light.
  16. ^ National Park Service Maritime History Project, Inventory of Historic Light Stations. Significant Unmanned Aids.
  17. ^ Lighthouse Depot, Gravelly Shoal Light/Charity Island.[dead link]
  18. ^ Charity Island ferry service.
  19. ^ us-lighthouses.com on Gravelly Shoal Light.

Further reading[edit]

External links[edit]