Architecture & Structure
A reinforced concrete offshore lighthouse: functional, massive, and built to withstand the open waters of Lake Michigan.
Design and construction
The Lansing Shoals Light Station is a purely functional structure with very little ornamentation, a departure from earlier Great Lakes offshore lighthouses. It consists of three main components: a square concrete pier foundation, a one-story reinforced concrete station building, and a three-story reinforced concrete tower topped by a cast iron and glass third order lantern.
It was originally planned as a two-story steel structure with a two-story tower, identical to the Milwaukee Breakwater Light Station. The design was altered when engineers decided to expand the basement to include four bedrooms for the keepers. This allowed the building above the pier to be reduced to one story, though the tower had to be increased to three stories to maintain the proper focal plane for the optic.
The concrete pier
The structure's foundation is a concrete pier measuring 74 feet square. It was constructed from four rectangular concrete caissons, each measuring 20 feet wide by 54 feet long by 21 feet deep. These caissons were fabricated at the U.S. Engineer caisson plant in Milwaukee, Wisconsin, using the same forms that produced the caissons for the Milwaukee Breakwater Light.
Unlike the Milwaukee Breakwater, where caissons were laid parallel, the Lansing Shoals caissons were positioned at right angles to one another, the long side of one meeting the short side of another to form each side of the square. The central opening was filled with rock. The pier's sides were strategically oriented facing north, south, east, and west so that the heaviest seas, arriving from the southwest and northeast, would split on the corners.
The four-caisson foundation is capped with a steel-reinforced concrete slab 7.5 feet thick. The outer perimeter supports concrete walls 36 inches thick that enclose the basement. A 12-inch thick steel-reinforced concrete slab caps the basement walls and serves as the pier's main deck.
The pier's outer walls are pierced by twenty-seven round port-light windows, sealed on the outside with metal covers. Two sets of metal double-doors near the waterline, one on the north side and one on the south, originally allowed supplies and machinery to be loaded directly into the basement from vessels moored alongside.
A belt of steel plating wraps around the pier from below the waterline to the port-light windows. At the northwest corner, the entire face is protected by vertical sheets of steel plating. At the northeast corner, the narrow belt was ripped away by the freighter collision of 1993.
The main building
The station building sits centered on the pier deck. It is one story tall, measuring 37 feet square, and is built of reinforced concrete on a structural steel framework. Each wall is divided into three bays separated by pilasters, with a door or window centered on each bay.
The building originally contained five rooms on its main level: a central foyer with staircases ascending to the tower and descending to the basement, a small bathroom, a combined living room and dining room running the full west side of the building, a kitchen with built-in cabinetry, and a large boat storage room on the eastern third. Two large garage-style door openings on the north and south walls provided access to the boat room.
The building has a flat roof that was originally enclosed by an iron pipe railing. A cylindrical metal flue projects from the northwest corner of the roof, and a taller flue extends from the roof up the north side of the tower. A metal pedestal on the roof's southwest corner formerly supported a fog signal device.
As a protective maintenance measure following automation, all windows and boat room doors were sealed with brick and mortar, and the station building was sprayed with a coat of gunite (a stucco material of cement, sand, and water) to reduce maintenance costs and help prevent vandalism.
Basement
The basement is accessed by nineteen stairs descending from the foyer. The eastern two-thirds contained work and storage space, equipment for operating the station, storage rooms for coal, oil, and paint, and two large storage tanks. A small corridor led to the metal double-doors in the pier's exterior wall for loading supplies directly from vessels.
The western one-third of the basement was an unusual feature: four separate bedrooms for the keepers, each with a closet, arranged along a narrow hallway with a shared bathroom. To reduce noise and fumes from the machinery side, the two areas were separated by a ventilated hallway, and the bedroom floors were raised sixteen inches above the equipment area. This configuration was possible because engineers at the Indiana Harbor, Calumet Harbor, and Chicago Harbor Light Stations had demonstrated the ability to build offshore basements that were both dry and warm. The basement originally received natural light through the pier's port-light windows, all of which were sealed when the station was automated.
The light tower
The three-story tower rises from the center of the station building's flat roof. It has a distinctive stepped profile, resembling a set of stacking blocks: the first level is 13 feet square at the base, the second is 12 feet square, and the third is 11 feet square.
Like the main building, the tower has a steel framework with reinforced concrete walls. Each story is accessed by flights of metal stairs with double-pipe handrails. The interior rooms on each level were painted different colors: green on the first story, pink on the second, and light green on the third-story watch room.
The tower's third story served as the watch room, containing the equipment for operating the light and fog signal. The lighthouse's original diaphone fog signal resonators remain positioned on both sides of the south window on this level, though they no longer function. A slanted metal ladder with twelve rungs in the center of the watch room provides access to the lantern above.
The lantern
The cylindrical third order lantern sits atop the tower. Because it is smaller than the tower's roof, a gallery surrounds it, enclosed by a two-tiered iron pipe railing. The lantern is composed of three sections: a parapet of cast iron panels at the base, glass panes held in place by helical cast iron astragals in the middle, and smaller cast iron panels with vents connecting to triangular iron roof plates above, topped by a cylindrical ventilator.
The lantern originally housed a third order Fresnel lens illuminated by a 500-watt incandescent electric lamp, producing an occulting white light visible for 16 nautical miles. The Fresnel lens remained in service after the station was automated in 1976, and was not dismantled until 1985 when it was replaced with a solar-powered 190-millimeter acrylic optic. The lens is now on display at the Michigan Historical Museum in Lansing. Today, a modern VRB-25 Marine Rotating Beacon occupies the lantern, with a focal plane 69 feet above the water, signaling a white flash every 10 seconds visible for 15 miles.
A RACON radar beacon and modern fog signal are mounted on the gallery deck. A full-size door in the lantern wall provides access between the lantern room interior and the outside gallery.
Changes over time
The most noticeable changes to the Lansing Shoals Light Station are the absence of several features originally installed on the pier deck and station building roof, likely removed during or after automation in 1976. These include two radio beacon antennas (self-supporting metal skeletal towers on the pier's northeast and northwest corners), a boat crane on the southeast corner, metal boat tracks on the deck, chain and pipe railings around the pier deck and building roof, a flagpole on the building's northeast corner, and two additional cylindrical metal flues alongside the tower.
The original light and fog signals have been replaced with modern equipment. The Fresnel lens stayed in service until 1985, nine years after automation, and is now displayed at the Michigan Historical Museum in Lansing. The daymark has changed too. The railings and lantern were originally painted a darker color contrasting with the lighter tower walls, then later repainted to match.
Despite these changes, the property's character and appearance remain essentially unchanged from its period of significance. The Lansing Shoals Light Station continues to operate as a Federal aid to navigation.
References
Architectural descriptions are drawn from the National Register of Historic Places Nomination Form (Section 7), Lansing Shoals Light Station, NPS, 2005. Additional construction details from LighthouseFriends.com.