Navigation Structures at Pentwater Harbor

Pentwater Pierhead Lights

Pentwater pier, showing south (left) and north (right) pierhead lights
Location	West End of Lowell St., Pentwater, Michigan
Year first constructed	south: 1937 / north: 1997
Year first lit	1873
Automated	1917
Foundation	concrete pier
Construction	steel skeleton tower (south) / cylindrical "D9-type" tower (north)
Focal height	south: 48 feet (15 m) / north: 43 feet (13 m)
Original lens	red 6th-order Fresnel lens
Current lens	both: 12-inch (300 mm) optic
Characteristic	0.5sec flash, 4.5sec eclipse
Fog signal	3sec every 30sec
ARLHS number	south: USA1270 / north: USA594
USCG number	7-18620 and 7-18630
Navigation Structures at Pentwater Harbor
U.S. National Register of Historic Places
Coordinates
Area	less than 1 acre (0.40 ha)
NRHP Reference #	00001638
Added to NRHP	January 11, 2001

The Navigation Structures at Pentwater Harbor are navigational structures located at the west end of Lowell Street in Pentwater, Michigan. They were listed on the National Register of Historic Places in 2001.

History

In 1855, Charles Mears constructed a 70-foot-wide (21 m) channel from Pentwater Lake to Lake Michigan, lined with timber cribbing, to accommodate his lumbering interests. In 1858, he built a pier extending over 600 feet (180 m) into Lake Michigan where ships could dock. Additional pier structures were built to line the channel. The first incarnation of the channel was relatively shallow, but Mears continued to improve it, and by 1865 it was deep enough that a lake-going steamer, the Daylite, was able to sail into Pentwater Lake.

In 1868 the US government began widening and improving Mears's channel. The channel was widened to 150 feet (46 m) and dredged to a depth of 16 feet (4.9 m). Two piers were constructed, and in 1873 a timber-framed lighthouse, 33 feet (10 m) high, was built on the south pier. A red 6th-order Fresnel lens was installed. A life-saving station was constructed on the north pier in 1887, and in 1917 the pierhead light was automated.

In 1937, the entire pier structure was replaced by the Army Corps of Engineers with a concrete pier. At the same time, the timber-framed lighthouse was replaced with a steel skeleton structure, and the optic replaced with a lens. Most of the life-saving station site, with the exception of the flag tower, was demolished in 1958. A second light was erected on the north pier in 1997.

Description

The Pentwater navigational structures consist of two concrete piers extending into Lake Michigan. At the end of the north pier sits a cylindrical modified "D9-type" tower topped with a 300-millimeter flashing green acrylic optic at a focal plane of 43 feet (13 m). At the end of the south pier sits a steel skeleton tower topped with a 300-millimeter flashing acrylic optic at a focal plane of 48 feet (15 m).