Split Rock Light Station

About this property

Split Rock Lighthouse is a lighthouse located southwest of Silver Bay, Minnesota, US on the North Shore of Lake Superior. The structure was designed by lighthouse engineer Ralph Russell Tinkham and was completed in 1910 by the United States Lighthouse Service for $75,000, including the buildings and the land. It is considered one of the most picturesque lighthouses in the United States. Split Rock Lighthouse was built in response to the great loss of ships during the famous Mataafa Storm of 1905, during which 29 ships were lost or damaged on Lake Superior. One of these shipwrecks, the Madeira, is located just north of the lighthouse. The lighthouse stands on a 133-foot (41 m) sheer cliff eroded by wave action from a diabase sill containing inclusions of anorthosite. The octagonal building is a steel-framed brick structure with concrete trim on a concrete foundation set into the rock of the cliff. It is topped with a large, steel lantern which features a third order, bi-valve type Fresnel lens manufactured by Barbier, Bernard and Turenne Company in Paris. The tower was built for a second-order lens, but when construction went over budget, only enough funding remained for the smaller third-order lens. The lens floats on a bearing surface of liquid mercury which allows near frictionless operation. The lens is rotated by an elaborate clockwork mechanism that is powered by weights running down the center of the tower which are then reset by cranking them back to the top. When completed, the lighthouse was lit with a kerosene oil vapor lamp. At the time of its construction, the area had no roads. All building materials and supplies arrived by water and were lifted to the top of the cliff by crane. The lamp was first lit on July 31, 1910. The lighthouse soon became a tourist attraction for sailors and excursion boats thanks to its scenic location. So much so, that in 1924 a road (now Minnesota State Highway 61) was built to allow land access. In 1940, the station was electrified, the lamp was replaced with a 1000-watt electric bulb, and the incandescent oil vapor lamp was moved to Au Sable Point Lighthouse in Northern Michigan. Split Rock was upgraded with a fog signal housed in a building next to the light tower. The original signal was a pair of sirens driven by two Franklin 30 hp (22 kW) gasoline-driven air compressors manufactured by Chicago Pneumatic Tool Company. In 1932 gasoline engines were replaced with diesel engines. The steam sirens were replaced with a Type F-2-T diaphone (be-you) type signal in 1936. The station and the fog signal were electrified four years later, but discontinued in 1961.

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Property data from the National Register of Historic Places, National Park Service (public domain).

Description adapted from Wikipedia under the Creative Commons Attribution-ShareAlike 4.0 International License.

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