The 17.23 Definition: Jones Act--"Vessel" refers to a specific type of watercraft that has been determined to be subject to the Jones Act, a federal law that provides for the rights of seamen in the United States. This vessel must be used for maritime transportation for business purposes and must be a US-flagged vessel. The types of vessels subject to the Jones Act include cargo ships, tankers, tugboats, supply vessels, fishing boats, ferries, yachts, and other vessels that transport goods or passengers in navigable waters.