By James Heinz
Between 1987 and 1994, fourteen Avenger class mine counter measure (MCM) ships were built in Wisconsin for the US Navy. All but two were built at the now gone Peterson Brothers shipyard in Sturgeon Bay, and the other two at Marinette Marine, now Fincantieri Marine, on the other side of Green Bay.
And two of these ships are deployed to the Straits of Hormuz as you read this article.
The AVENGER courtesy of Wikipedia
Photo at top of page: AVENGER courtesy of Wikipedia
The Avenger class ships were built with a wooden hull and superstructure covered with fiberglass that does not produce the same magnetic signature as a steel ship and does not detonate magnetic mines. The wooden construction also provides the hull with the flexibility to withstand the shock of nearby explosions. Douglas fir was used for most of the ship’s structure, with laminated Alaskan cedar for the inner layer of the diagonal planking and white oak for the transverse frames. The ships are still vulnerable to acoustic and pressure mines.
The Avengers displace 1,312 tons, are 224 feet long, 39 feet wide, and draw 15 feet of water. Each is powered by four 600 hp diesel engines that drive two propeller shafts. They can cruise at 14 knots and have two electric maneuvering motors and a crew of 8 officers and 76 enlisted men.
The DEFENDER courtesy of Wikipedia
Instead of guns or missiles, they are equipped with a powerful sonar and low light TV system that enables them to detect and classify mines and a remotely operated vehicle equipped with cable cutters and explosive charges to detonate mines in place. That powerful sonar is what the USS DEFENDER used in 2000 to find the fish tug LINDA E. that had gone missing in 1998 off Port Washington.
As of April 2026, USS CHIEF and USS PIONEER were reported to be enroute to the Straits of Hormuz. Avenger class vessels had been stationed in the Persian Gulf since 1990. All four remaining AVENGERs are scheduled to be retired in 2027 and to be replaced by Littoral Combat Ships as mine hunters.
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James Heinz is the Wisconsin Marine Historical Society’s acquisitions director. He became interested in maritime history as a kid watching Jacques Cousteau’s adventures on TV. He was a Great Lakes wreck diver until three episodes of the bends forced him to retire from diving. He was a University of Wisconsin – Milwaukee police officer for thirty years. He regularly flies either a Cessna 152 or 172.
