Any officer endorsement issued for service on Great Lakes and inland waters self-propelled vessels, excluding towing vessels, is valid on all of the inland waters of the United States as defined in 46 CFR 10.107 and described below.
In the hierarchy of coast guard licenses, Great Lakes, is higher than Inland. This means that a 100 GRT Master Great Lakes can operate, within the bounds of the license, on Inland waters. However, a 100 GRT Master Inland is not allowed to operate on the Great Lakes as a 100 GRT Master.
What is the definition of the Great Lakes?
There are five lakes, which are Lake Superior, Michigan, Huron, Erie, and Ontario. The Great Lakes are on or near the U.S.-Canadian border. Lake Michigan is the only Great Lake that’s entirely within the United States.
For the purpose of calculating service requirements for a Great Lakes endorsement, this means the Great Lakes and their connecting and tributary waters.
This includes the Calumet River as far as the Thomas J. O'Brien Lock and Controlling Works (between miles 326 and 327), the Chicago River as far as the east side of the Ashland Avenue Bridge (between miles 321 and 322), and the Saint Lawrence River as far east as the lower exit of Saint Lambert Lock.
For purposes of requiring MMCs with rating endorsements, the connecting and tributary waters are not part of the Great Lakes.
We hope this made your life a little easier and if you have other questions the MM-SEAS team is always here to help!
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About the author
Nate Gilman is President and Co-Founder of MM-SEAS. He hawsepiped from the deck to a 3rd Mate Unlimited license with full STCW compliance over more than 15 years at sea, and is a veteran of the NOAA Commissioned Corps. He works directly with the National Maritime Center, USCG-approved training schools, and vessel operators on credentialing policy, and writes on sea service documentation, evaluation standards, and how mariners move up the license ladder.
