United States Coast Guard Charter Boat Captain's license

A United States Coast Guard Charter Boat Captain's Credential refers to the deck officer qualifications on a Merchant Mariners Credential which is a small book that looks similar to a passport and is issued by United States Coast Guard for professional mariners in the United States commanding commercial passenger vessels up to 100 gross tons as a Master, captain or skipper. It may contain a sailing endorsement for sailing vessels and/or a commercial towing endorsement for vessels engaged in assistance towing.

Source: Wikipedia — United States Coast Guard Charter Boat Captain's license (CC BY-SA 4.0)