South Manitou Island Steam Whistle (U.S. National Park Service)

A historic black and white aerial photograph of several buildings and a lighthouse along a sandy lakefront beach. — Historic aerial view of the lighthouse complex. The building closest to the water is the fog signal building.
NPS Photo

Weather can impact travel at a moment’s notice—whether driving, flying, biking, or boating. Fog is one of those tricky weather events. It can become so thick that you can’t see your hand in front of your face. That is a major problem if you are navigating a large ship full of cargo through the narrow Manitou Passage.

Grand Traverse Herald, 12 August 1885

We have had a great deal of foggy weather thus far this season. According to the record kept by Mr. Knudson, the lightkeeper, we had, during the month of May 66 ½ hours, in June 83 hours, July, 30 hours of fog, due to the late departure of the ice last spring. ¹

In the 1830s, Lake Michigan saw a significant increase in steamship traffic, due to the 1825 opening of the Erie Canal. Steamships burned wood to create steam, which meant they had to stop frequently to refuel. With a plentiful hardwood forest, a natural deep harbor, and a perfect position along most shipping routes, South Manitou Island became the ideal pit stop for steamships.

“In 1836, over 500 ships passed through the Straits of Mackinac into Lake Michigan each year. Because of the large number of ships traveling into and out of Lake Michigan, and the often-violent weather in the region, the risk of a shipwreck occurring was significant.”²

A black and white image of a tall cylindrical building on a small hill with a small T-shaped building to the left. — View looking south towards the South Manitou Island Light Station, 1883
NPS Photo / Historic Structure and Cultural Landscape Report

In response to these weather challenges, South Manitou Island’s first lighthouse was built in 1840. “It remained the only lighthouse in the vicinity for more than a decade.”³. However, the lighthouse alone wasn't enough to ensure the safety of ships during inclement weather. If the light isn't visible, it is of no help to the captain. Low visibility was the cause of many shipwrecks in the Manitou Passage. The Francisco Morazan, for example, ran aground on South Manitou Island in 1960 during a blinding snowstorm. Another shipwreck caused by fog was described in a 1890 article printed in the Leelanau Enterprise:

Leelanau Enterprise, 19 June 1890

The cargo of the steamer W.J. Averill, which stranded upon South Manitou Island in the fog, is insured for $35,000. In addition to corn and oats in the hold, the Averill carried on deck 200 tons of flour and feed and some elevator machinery for Ogdensburg valued at $1,200. The floor and feed jettisoned with the machinery was valued at $5,000. We understand that people on the island saved several thousand bushels of dry corn, and several hundred bags of feed. ⁴

By 1860, as maritime activity surged, “there were 1,459 ships plying the Great Lakes, and South Manitou Island's harbor was the most frequently used storm refuge on the lakes.”⁵ Fog signals became essential for safe travel through the Manitou Passage. These signals helped ships navigate safely in foggy, snowy, or stormy weather when the light from a lighthouse might be hard to see.

Recognizing the importance of South Manitou Island’s sheltered bay, “the Federal Government established a lighthouse and fog signal bell on the island in 1839.”⁶

A gold, cylindrical tube with a silver base sits on top of a wooden pedestal. — A 10-inch steam locomotive whistle used to signal in fog on South Manitou Island
NPS Photo / D. Fenlon

In 1858, the fog signal “was a bell weighing 1000 pounds and was struck 'by means of machinery.'”⁷ A fog signal house was built to keep this bell safe and secure.⁸

Technology changed, and in 1874, South Manitou Island received the first steam-powered fog signal whistle on the Great Lakes.⁹ A new fog signal called for a new building, which was built in 1875. This new wooden building had a boiler that could be fired with coal or wood, creating steam. “The steam was piped to a single 10-inch locomotive whistle located atop the roof of the building.”¹⁰

In case something went wrong with the steam-powered fog signal, the old fog bell remained in place until it was retired in 1879.

Transitioning from mechanical bells to steam-operated fog signals was no small feat. It required a substantial investment in equipment and was labor intensive. After the tower was built, an assistant was hired to help the keeper. A second assistant was hired after the steam fog signal building was added.¹¹

Grand Traverse Herald, 19 March 1896

B. C. Green has just been appointed second assistant keeper at the light and fog signal station at South Manitou, and will begin his duties there in a short time. ¹²

David Clary notes in The Life of the Keepers as Reflected in Their Official Journals, the introduction of the steam fog signal significantly increased the maintenance responsibilities of the keepers. He observed that “the [keepers'] journals indicate that throughout the 20th century the fog signal accounted for more of the men's time as it grew in navigational importance. Ships became larger and avoided the coasts. The light was often of less service to them than the signal that could alert them to the proximity of the fog shrouded shores.”¹³

An aged black and white photo of a small rectangular building with a person leaning in the door frame. Two small cylindrical tubes and two large cylindrical tubes stick out of the roof. — "The fog horn on the South Manitou Island has begun to sing its beautiful ditty."
--Grand Traverse Herald, May 8, 1884 [19]
NPS Photo

Grand Traverse Herald, 4 June 1885

We had an abundance of music last week. The fog signal howled and bellowed, and annoyed the citizens for nearly fifty hours in succession. It's terrible! It blows every minute and the thing became wild the other night and went "on a lark” of its own. It began blowing and would not cease for the unusual interval but kept on sounding until it had exhausted all its steam, and upon examination it was found to have swallowed a nail which lodged in the larynx of the windpipe and caused it to choke, and it choked it to death. It is all right now. ¹⁴

Leelanau Enterprise, 12 May 1932

The fog signals of North and South Manitou lighthouses, and the Manitou light ship, were in use almost continuously from Friday until Monday noon. ¹⁵

A grainy black and white photograph with sand and vegetation in the foreground. There are two sailboats in the water on the left. On the right are two small buildings with stacks, and a lighthouse with a long structure attaching it to a small building. — View looking south towards the South Manitou Island Light Station, 1883.
NPS Historic Structure and Cultural Landscape Report

"This is one of the first known photographs of the South Manitou Island Light Station and shows it as it appeared in 1883.”¹⁶ To the left of the lighthouse are two individual, duplicate fog signal buildings built in 1879. The metal smokestacks and steam whistles are visible on the roof of the two buildings. For almost 20 years, each fog signal building housed one boiler.¹⁷ In 1897, one of the fog signal buildings was relocated to connect the two fog signal buildings together. This allowed all the equipment to be located within one structure.¹⁸

In the United States, every fog signal had a specific sequence of sounds and silences. On the roof of South Manitou Island’s fog building, there were two metal smokestacks and two 10-inch steam whistles. “Each [produced] an eight second blast between 52-second silent intervals.”²⁰ This unique and standardized sound pattern helped sailors understand their location even in thick fog.

Grand Traverse Herald, 17 December 1885

A cold northeaster has been prevailing from nearly every direction for nearly a week, accompanied by dense snow and fog. The fog signal has been rendering the air with its ever glorious music almost constantly since. It is hoped that navigation will soon close, that it may have a rest, and that the citizens may also have a rest. ²¹

Technology Advancements in the 20th Century

Technology continued to change rapidly in the 20th century. Prior to the 1934 shipping season, the fog signal equipment transitioned from the steam whistle to an air diaphone system powered by diesel generators and air compressors.²² This new technology moved the fog signal from the fog buildings to the lighthouse tower so that the sound could reach a larger area. To do this, new equipment was needed, and some old equipment had to be rearranged.

Drawing of a building in the shape of an upside-down T. — Diagram of the layout of the combined Fog Signal Building, 1941.
NPS Historic Structure and Cultural Landscape Report

A brown arched furnace with a cylindrical duct next to it. — An old furnace found in the Machinery Room of the Fog Signal building on South Manitou Island. The furnace was installed by the Coast Guard.
NPS Photo

Details of drawing entitled South Manitou Island Installation of Air Diaphone to Replace Steam Boilers. — Details of drawing entitled "South Manitou Island Installation of Air Diaphone to Replace Steam Boilers," 1934.
NPS Historic Structure and Cultural Landscape Report

In 1897, when the fog signal buildings were attached, the smokestacks, steam whistles, and new boilers were placed on the eastern side of the two buildings. This part of the building became known as the “Machinery Room”. ²³ In 1934, the steam stacks and whistles were removed, and a brick chimney and metal vent stacks were installed. Two diesel generators and a furnace were installed in the Machinery Room. Just north of the building, a gasoline tank was buried to keep these generators running. The generators were used to pressurize air that was then transported to four air tanks at the base of the lighthouse. From those tanks, another airline went up to the diaphone and to the horn located at the top of the tower in the watch room. ²⁴

A black and white photo showing a piece of machinery with a large wheel. — One of the two replacement engines installed at South Manitou circa 1902.
NPS Photocopy / Ann Razo

For almost 10 years, the purpose of the generators was to power the diaphone. It wasn’t until 1943, when the lighthouse light converted from kerosene to electricity that the generators were used for electricity and to power the light inside the lighthouse.

Just like the steam fog whistle, the diaphone had its own sequence of sounds and silences. Ronald Rosie, who lived on South Manitou Island from 1933 to 1941, was the son of the last lighthouse keeper before the United States Coast Guard assumed responsibility of the light. In a 2009 conversation with park employees, he recounted how winter could complicate the use of the air diaphone and its sound sequence:

Ronald Rosie Interview Diaphone at SMI Lighthouse
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Ronald Rosie, son of the last lighthouse keeper on South Manitou Island, discusses how harsh winters could complicate the use and the sound of the air diaphone at the lighthouse.

Credit / Author:

NPS Interview
Audio Transcript

Ron Rosie

That foghorn had a diaphragm in there, about this big around and it tapered down. And when the air hit it, it would clatter and that’s what made the sound. Well, the snow would go in there and freeze the dang thing. So, you had to go up and take this big plate off the back, with about 8 bolts in it. Go outside with a stick and ram that thing back out of there. You always had a spare one and you’d jam it back in and put the cover back on and start the air motor again.



I can show you in the tower, there’s a little table up there. It’s probably, oh about this high, and the air horn that ran the cam, that tripped the horn would freeze up. So, you cut a hole in the table and put a lamp under there. So, the heat lamp warm kept the motor from freezing up.



We had a big cam and on that cam was one bump, that was seven seconds. About every minute it blew seven seconds. That thing would go around like this…



Interviewer

To make the revolutions.



Ron Rosie:

…then she’d trip and blow and drop and do it again. Kept going. Never stopped.



See and then the [unintelligible] that we had down at the fog signal. We had two of them down there. The front shoulder was the engine, the back shoulder was the air compressor. And they were big. The big flag was about this high on each end. And you regulate the speed of the engine, once you got the pressure up. Everybody said it took so long, but it well you can't believe everything you hear. We knew how long it took.



And you heated it with a torch. You give it the air and it would take off. And you'd, you regulate the speed of the engine to the air, certain air pressure and you could keep the horn at seven second because the pressure of the air would fluctuate the motor would run faster or slower.



So, you had the engine run at exact speed and depending on the weather. But you could regulate the engines by a notch or two on a lever. For the warning, you time it with a stopwatch. Right at the fog signal, that’s how you kept it even.



Interviewer:

Well, that took a little bit of work to figure that out.



Ron Rosie:

Well, but back in them days, that was a must. There was none of this maybe, perhaps, a little bit don’t mean no difference. It didn't work that way.



Interviewer:

Right, it had to happen.



Ron Rosie:

It had to be right, or it wasn't going to work. A lot of them say well, well hard to do. No, you got used to it.

Four children and an adult standing against a building with zig-zag siding — Ronald Rosie (middle) and younger brother Roger (fourth from left) with students and teacher in front of the South Manitou Island School house in 1937.
NPS Photo

In another interview, Ron recounted how he and his family became used to the foghorn sounds:

Ronald Rosie Interview Foghorn Sound
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Ronald Rosie, son of the last lighthouse keeper on South Manitou Island, recalls being so used to the sound of the foghorn that he didn't always realize when it was sounding.

Credit / Author:

NPS Interview
Audio Transcript

Ron Rosie:

You know, you could blow that foghorn for 3 or 4 days and we never heard it in the house. We had to stop and see if it was listening, listen to see if it was blowing. You got used to it. You didn't pay attention to the darn thing.



Interviewer:

It was like background noise for you.



Ron Rosie:

People would come visit you and they just come screaming out of bed.



“What's the matter with you? “That horn blowing” “I say, was it blowing?” [Interviewer laughing]

But anyway. Yeah, it was quite a thing.

Over the years, ships became larger and deeper, forcing them to move further out into Lake Michigan, where the lighthouse light could not reach. As a result, the fog signal began to replace the visual guidance of the lighthouse. While sound was less accurate for pinpointing location, it carried farther and performed reliably in all weather conditions.

“Eventually, technology made the South Manitou lighthouse obsolete, and the United States Coast Guard closed the station in 1958, ending over one century of service.” ²⁵ With the absence of a caretaker, the lighthouse and surrounding buildings began to experience deterioration.

A run-down, rectangular building with peeling white paint and a red roof. — Fog Whistle Building on SMI before restoration
NPS

A T shaped white building with a bright red roof surrounded by a sandy beach. — Fog Whistle Building on SMI after restoration
NPS

In 1970, South Manitou Island became part of Sleeping Bear Dunes National Lakeshore. Throughout the last 50 years, the park has worked to restore many of the historic buildings throughout the island. One of these restoration projects included the fog signal building. In 2023 the building’s roof was replaced. During this time, the roof, along with the exterior of the building were repainted.

A view looking up towards the sky at a grey steel funnel connected to a perpendicular pipe. A white building can be seen in the background. — The original diaphone horn can be found outside the South Manitou Island Visitor Center
NPS Photo

The original diaphone horn can now be seen outside of the South Manitou Island visitor center. It is stuck into the ground.

During summer months, visitors can reach South Manitou Island by ferry. On the island, visitors can hike, camp, and take a tour of the lighthouse tower. Learn more about visiting South Manitou Island.

Sources

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Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
“Leelanau Locals.” Leelanau Enterprise, 19 June 1890. Front page: https://digmichnews.cmich.edu/?a=d&d=LeelanauLE18900619-01.1.1&srpos=4&e=--1874---1935--en-10-LeelanauLE-1-byDA-txt-txIN-%22south+manitou%22+%2B+fog---------
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
"South Manitou Lighthouse." Terry Pepper's Seeing the Light, Terry Pepper, http://www.terrypepper.com/lights/michigan/southmanitou/southmanitou.htm.
"South Manitou Lighthouse Complex." National Park Service, U.S. Department of the Interior, www.nps.gov/places/000/south-manitou-lighthouse-complex.htm.
"Lighthouses of the Sleeping Bear Dunes National Lakeshore." National Park Service, 2019, https://npshistory.com/publications/slbe/brochures/lighthouses-2019.pdf.
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
“Grand Traverse Herald” 19 March 1896. Page 6. https://digmichnews.cmich.edu/?a=d&d=GrandTraverseGTH18960319-01.1.6&srpos=1&e=-------en-10--1--txt-txIN-assistant-------GrandTraverseGTH18960319%252D01--
Au Sable Lighthouse." National Park Service, 1975, https://npshistory.com/publications/piro/au-sable-ls-1975.pdf.
"Manitou County South Manitou." Grand Traverse Herald, 4 June 1885. Page 6. https://digmichnews.cmich.edu/?a=d&d=GrandTraverseGTH18850604-01.1.6&srpos=6&e=-------en-10--1-byDA-txt-txIN-%22fog%22+%22south+manitou%22---------
“North Manitou” Leelanau Enterprise, 12 May 1932. Page 4 https://digmichnews.cmich.edu/?a=d&d=LeelanauLE19320512-01.1.4&srpos=7&e=--1874---1935--en-10-LeelanauLE-1-byDA-txt-txIN-%22south+manitou%22+%2B+fog---------
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
“Miller’s Hill.” Grand Traverse Herald, 8, May 1884. Page 4. https://digmichnews.cmich.edu/?a=d&d=GrandTraverseGTH18840508-01.1.4&srpos=5&e=-------en-10--1-byDA-txt-txIN-%22fog%22+%22south+manitou%22---------
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
“Benzie County South Manitou.” Grand Traverse Herald, 17 December 1885. Page 6. https://digmichnews.cmich.edu/?a=d&d=GrandTraverseGTH18851217-01.1.6&srpos=8&e=-------en-10--1-byDA-txt-txIN-%22fog%22+%22south+manitou%22---------
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf
Evans, Quinn. Historic Structure and Cultural Landscape Report: South Manitou Island Light Station. Sleeping Bear Dunes National Lakeshore, January 29, 1999. http://www.npshistory.com/publications/slbe/so-manitou-island-light-station-hsr-clr.pdf