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U.S. Coast Guard Cutter MOBILE BAY (WTGB 103)

Sturgeon Bay, Wisconsin


USCGC MOBILE BAY is the one of nine cutters in the Coast Guard’s “Bay” Class of icebreaking tugs.  She is one of two Bay Class ships equipped with a 120-foot Aids-to-Navigation barge operating on the Great Lakes.

Homeported in Sturgeon Bay, Wisconsin, the ship is located in the town once known as the “Shipbuilding Capital of the Great Lakes.”  Built by the Tacoma Boatbuilding Company, MOBILE BAY was launched on Veteran’s Day, November 11, 1978 and was commissioned on September 2, 1979.  The Barge was built by Marinette Marine Corporation, Marinette, WI; the Coast Guard accepted Barge 12002 on May 15, 1992.   

CGC MOBILE BAY has dual responsibilities in assisting safe navigation on the Great Lakes.  The ship’s primary mission, and the one for which she was originally designed, is icebreaking.  MOBILE BAY conducts its icebreaking mission from mid-December through mid-April. During the winter months, the cutter detaches from the barge and breaks ice in the Northern Lakes, operating mostly in Green Bay, the Straits of Mackinac, and the St. Mary’s River.   

The ship was designed with icebreaking in mind. Its high horsepower, specialized hull design, and “slick” bottom paint make this cutter one of the most efficient icebreakers in the world today.  The cutter’s hull lubrication system, or “bubbler”, further increases its icebreaking capabilities.  This system pumps air through openings in the hull below the waterline reducing ice friction, allowing the cutter to pass easily through ice fields.  At full power and using all four sections of the “bubbler system” manifolds, MOBILE BAY is capable of breaking up to 30-inches of ice in continuous mode.  

In addition to the duty of icebreaking, when notched into CGB 12002, MOBLE BAY’s ample horsepower combined with the barge’s bowthruster create a highly maneuverable platform for servicing floating aids to navigation, or what is commonly called buoys.  CGB 12002’s 20-ton capacity crane and large buoy deck area enable the Tug & Barge combination to effectively maintain over 100 buoys in Green Bay and upper Lake Michigan. 

MOBILE BAY’s other missions include: Maritime Law Enforcement, Search and Rescue, Environmental Pollution Response, and Homeland Security.  

CGC Mobile Bay
Last Modified 9/19/2013