U.S. flag towing vessel owners and operators are reminded that the vessel must possess the appropriate certificates and endorsements for the intended voyage. International certificates and certain equipment is required prior to embarking on international voyages1 including voyages to Canada and Mexico. Failure to present valid international certificates and demonstrate operation of equipment may lead to a Port State Control (PSC) detention, schedule delays, and additional costs to owners and operators
https://www.dco.uscg.mil/Featured-Content/Mariners/Marine-Safety-Information-Bulletins-MSIB/