Sentinel Island Light Station: The History, Physics and Mechanics

Sentinel Island Light Station is a guide on an important water passage for Alaskan transportation and commerce, and the lighthouse is an excellent example in Alaska of Art Deco architecture. Sentinel Island Light station started operating on March 1, 1902. Sentinel Island was the first American lighthouse built in Alaska. Sentinel Island Light Station stands at the entrance to Lynn Canal, a heavily used transportation and trade canal located from the city of Juneau north to the cities of Haines and Skagway. The U.S. Lighthouse Bureau added a concrete Art Deco style lighthouse building to the site in 1935 that is an excellent example in Alaska of the popular architectural style. Sentinel Island Light Station continues to be functional today.

The discovery of rich gold deposits in the upper Yukon River area at the close of the nineteenth century caused a large increase in the number of ships navigating Lynn canal. In the late 1890s, watercraft of every description converged upon the Pacific Northwest ports to sail north. Once they passed British Columbia waters, there were few guides through the Inside Passage. Fog, rain, strong tides, and a rocky shoreline made this passage, especially for large steamers overloaded with prospectors and freight. Over three hundred accidents in Inside Passage waters were reported in 1898. Although Alaska's governors had been urging the U.S. Government to install navigation aids along Alaska's coasts for over a decade, only a few markers and buoys had been installed. Congress appropriated funds for the Sentinel Island Light Station that year. George James, a Juneau resident, received the contract and began construction of the Sentinel Island station in 1901. Sentinel Island Light Station started operating on March 1, 1902, which made the lighthouse one of the first two lighthouses ever built in Alaska.

"The original Sentinel Island lighthouse was a wooden, square, duplex keeper's residence with hipped cross gables and an integral light tower. A steel and glass lantern on top of the tower housed a fourth order Fresnel lens. The Sentinel Island light and fog signal house's rectilinear massing, flat roof, central tower, and stepped elevation planes." The total cost was $35,310, and there were no special techniques used in the creation of the lighthouse. The original lantern was moved to the new tower and the building continued to serve as the keeper's residence until the light was unmanned and automated in 1966 due to inflation and technological advances. In 1971, the U.S. Coast Guard demolished the deteriorated original residence by the method of lighting the place on fire.

The lighthouse has a focal plane of 86ft(26m). The lighthouse gives off a white flash every ten seconds. The base of the lighthouse is 51 ft (15.5 m), and the lighthouse is shaped as a square cylindrical reinforced concrete tower on the roof of square concrete fog signal building. The lighthouse has a solar-powered VRB-25 aerobeacon with the lighthouse's original 4° Fresnel lens on display at Alki Point Light in Seattle, Washington. The foundations of the lighthouse are made of concrete where the frame of the lighthouse is made of wood. Lighthouse was officially listed on the National Register of Historic Places, 2 December 2002, which is the nation's catalog of significant historic properties.

"Art deco is characterized by long, thin forms, curving surfaces, and geometric patterning. The practitioners of the style attempted to describe the sleekness they thought expressive of the machine age." Items made using the art deco style range from skyscrapers and ocean liners to toasters. Art Deco is all about machines, mass-production, metal and concrete and art deco architecture is the style of architecture that is primarily shown in the Sentinel Island lighthouse. This architectural style also has practical usage in that it creates sturdy functional buildings.

Bibliography

"Alaska Lighthouses" Russ Rowlett and the University of North Carolina

"Art Deco." Encyclopedia.com

Historic Light Station Information and Photography, Alaska" The US Coast Guard.