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USCGC MAKINAW during an icebreaking operation

Domestic Icebreaking

The Coast Guard was directed by Congress to acquire Great Lakes Icebreaking Capability to replace USCGC MACKINAW (WAGB-83) with funding provided in the 2000 budget.  As a result the Great Lakes Icebreaking Capability Replacement (GLIB) project was started with the primary purpose of meeting the heavy icebreaking requirements of the Great Lakes as spelled out under several federal mandates. Specifically, Executive Order NO. 7521 dated 21 December 1936 states "The Coast Guard ...... is hereby directed to assist in keeping open to navigation by means of ice-breaking operations .... channels and harbors in accordance with the reasonable demands of commerce."

Maintaining a reliable Great Lakes heavy icebreaking capability is essential. Great Lakes shipping operates on a 42 week shipping season to deliver 150 million tons of materials. Of those 42 weeks, 12 weeks require icebreaking services.

The costs of inadequate performance are real and substantial. Previous studies found Coast Guard Great Lakes total icebreaking services to have an estimated average annual outcome of $49-78M to industry alone. A 1995 Volpe study estimated the average annual outcome value of heavy icebreaking is at least $13-20M. These estimates are based on direct industry costs of least cost alternatives; they do not include any estimates of the consequences of higher costs in a highly competitive global market or the downstream impact in jobs or the larger economy.

In the past the USCGC MACKINAW (WAGB-83) was the only heavy icebreaking capability assigned to the Great Lakes and had been in service for more then 60 years. Her age made her very expensive and difficult to maintain.  And thus she was decommissioned in June 2006 where she now serves as a beautiful lakeside maritime museum in Mackinaw City, Michigan.  USCGC MACKINAW (WLBB-30) will maintain the long and proud traditions of Coast Guard service in the Great Lakes and will be the second cutter to carry this name. 

USCGC MACKINAW (WLBB-30) is designed to meet or exceed the following icebreaking characteristics:

Continuous Mode 3 knots ahead in 32" solid level ice
10 knots ahead in 14" solid level ice

2 knots astern in 30" solid level ice


3 knots ahead and 2 knots astern in 8' brash ice

Ramming Mode Average .5 knots ahead, backing and ramming in 42" solid level ice
  Average 0.5 knots ahead, backing and ramming in 5' refrozen brash ice
  Average 0.5 knots ahead, backing and ramming a 12' pressure ridge
  Fully penetrate a 10' pressure ridge in 4 rams or less within 30 minutes
Escort Vessels and Free Beset Vessels Cast in a 300' wide channel with a depth of 21'
  Back from existing track in 30" solid level ice and 12' brash ice
  Circumnavigate a beset 1000' Laker within 12 minutes in 32" solid level ice
  Flush 32" solid level ice and 12' brash ice from beset vessels and fixed structures
  Clear ice jams by flushing and ramming
Maneuverability Turn 180 degrees in a 300' wide 21' deep channel in 5 minutes in 32" solid level ice and 12' brash ice
  Turn 360 in her own length in 24" solid level ice
  Break out of track channel and turn 90 degrees within 30 seconds in 32" solid level ice
  Arrive and depart a standard berth in 32" solid level ice and 12' brash ice
  Extract herself from a stopped position at the end of rams under her own power



Last Modified 2/9/2015