|Builder:||Zenith Dredge, Duluth, Minnesota|
|Laid down:||16 January 1944|
|Launched:||7 April 1944|
|Commissioned:||1 September 1944|
|Decommissioned:||7 June 2006|
|Identification:||IMO number: 8635021|
|Motto:||Ace Of The Lakes|
|Class and type:||Iris or C|
|Displacement:||1,025 long tons (1,041 t)|
|Length:||180 ft (55 m)|
|Beam:||37 ft (11 m)|
|Propulsion:||2 × GM EMD 645E diesel electric engines|
|Speed:||14 kn (26 km/h; 16 mph) maximum|
|Range:||8,000 nmi (15,000 km; 9,200 mi) at 13 kn (24 km/h; 15 mph)|
The USCGC Acacia (WLB 406) was second to the last of a fleet of 39 similar 180-foot seagoing buoy tenders completed during World War II. Acacia was named after the former United States Lighthouse Service tender Acacia, the only tender sunk during World War II. Acacia is a multi-purpose vessel, nominally a buoy tender, but with equipment and capabilities for ice breaking, search and rescue, fire fighting, logistics, and other tasks as well.
Acacia was homeported in Port Huron, Michigan, Sturgeon Bay, WI, Grand Haven, MI and Charlevoix, MI. The ship's primary duty was maintaining more than 210 buoys, lighthouses, and other navigational aids. Her area of operation ranged from as far south as Calumet Harbor, south Chicago, to as far north as Little Bay de Noc, including Green Bay, Wisconsin; Sturgeon Bay, Wisconsin; and Wisconsin’s Door Peninsula.
Among her various duties were search and rescue of lost or disabled vessels and icebreaking assistance during the cold winter months. During the ice season, Acacia was one of several Coast Guard ice breakers engaged in Operation Coal Shovel, which keeps the channels between Toledo, Ohio and Detroit, Michigan open for the coal ships supplying power plants and industries in Detroit.
Acacia also worked with NOAA in their efforts to acquire accurate weather information and with the United States Fish and Wildlife Service when they stocked Lake Michigan with hundreds of thousands of yearling trout.
Acacia was decommissioned June 7, 2006 after 62 years of service. Acacia was the second to last of the 180-foot (55 m) vessels to serve. Although another ship was not assigned to Acacia's last home port, her duties were picked up then by newly commissioned USCGC Mackinaw which is equipped to handle buoy tending as well as ice breaking.
In late October 2009, Acacia steamed under her own power after more than three years of not running the main engines to Manistee, Michigan, where she has become part of the SS City of Milwaukee National Historic Landmark museum in an effort to give the general population the experience of being and working on board a Great Lakes buoy tender as well as a 1930s car ferry.
In 2006, the American Academy of Industry, an Illinois nonprofit group, planned to acquire the ship and turn it into a maritime museum in Chicago. Locations considered include Navy Pier, but also moorings along the Chicago River. The vessel, which was delivered in full working order with only her machine guns removed, was temporarily moored at Burns Harbor in Indiana. The U.S. Coast Guard had considered a sale to an unnamed African country, but when that fell through, found the Chicago group's request filed away. The donation was arranged through a transfer to the State of Illinois, which held title. On November 10, 2007 Acacia sailed from Burns Harbor, Indiana to her new home in Chicago in the north slip of the US Steel Southworks, located at the foot of South East 86th Avenue and Lake Michigan. However, in October 2009 the ship was transferred to the SS City of Milwaukee National Historic Landmark museum in Manistee, Michigan.