Every claim on this site is sourced and verifiable. This page explains where the data come from, how employment status is determined, and what limitations apply.
The universe of Jones Act–compliant tankers is drawn from the MARAD U.S.-Flag Oceangoing Vessel Inventory, which lists all U.S.-flagged, U.S.-built commercial ships over 1,000 gross tons. The tanker subset — 56 ships — represents every vessel currently eligible to carry coastwise cargo under 46 U.S.C. §55102 under 46 U.S.C. §55102.
Current vessel positions, speeds, destinations, and port call records are sourced from VesselFinder, which aggregates Automatic Identification System (AIS) transponder data broadcast by each vessel. AIS is a maritime safety system required by international convention for ships over 300 gross tons on international voyages and ships over 500 gross tons otherwise.
Actual Time of Arrival (ATA) and Actual Time of Departure (ATD) data are sourced from VesselFinder's port call log, which records port visits logged via AIS. Where a vessel shows no ATD, this indicates it has arrived at a terminal but not yet departed — consistent with active loading or discharging operations, not idleness.
Ships showing extended presence at known shipyard locations (Goseong, South Korea; Veracruz, Mexico) are classified as in scheduled drydock or maintenance. Jones Act ships are not required to undergo maintenance at U.S. yards, and routinely use foreign shipyards for major repairs and class renewals.
A vessel is classified as Employed if it meets any one of the following criteria at the time of the snapshot:
Ship AIS reports a speed greater than 2 knots, indicating active transit. Includes both loaded (cargo aboard) and ballast (repositioning to load port) voyages — both represent normal commercial employment.
Ship has a recorded port call within the past 14 days, has a listed destination, or has a recorded arrival (ATA) with no departure yet logged. The absence of an ATD means the ship has not yet left, not that it has been idle — ships at berth loading or discharging have no ATD until they sail.
Ship is at a known shipyard undergoing scheduled maintenance, class renewal, or repairs. Drydocked ships are fully employed — their crews are working and they will return to cargo service. Scheduled maintenance is a routine and necessary part of ship operation.
A vessel in ballast transit — steaming empty from a discharge port to a load port — is just as employed as one carrying cargo. Ballast voyages are an inherent and predictable part of tanker operations and do not indicate idleness or lack of demand.
This tracker documents fleet-wide employment status at a point in time. It does not show cargo volumes, freight rates, charter arrangements, or ship utilization rates over time. The positions shown are approximate — derived from AIS region descriptions and last/next port data rather than precise GPS coordinates.
AIS data can have gaps, particularly for ships in certain geographic areas or with transponder issues. Where position data was unavailable, ships are plotted at their last known port location.
The fleet list reflects ships in active commercial service. Ships in long-term layup, ships that have been sold or scrapped since the MARAD inventory was published, and ships under construction are not included.
Section 27 of the Merchant Marine Act of 1920, commonly called the Jones Act, requires at 46 U.S.C. §55102 that merchandise transported by water between points in the United States be carried on ships that are:
The vessel must have been constructed in a U.S. shipyard. Foreign-built ships are ineligible even if U.S.-documented and U.S.-crewed.
The vessel must hold a Certificate of Documentation with a coastwise endorsement issued by the U.S. Coast Guard under 46 U.S.C. §55102(b)(2). This is distinct from simply flying the U.S. flag.
The vessel must be wholly owned by U.S. citizens, with at least 75% of equity and control held by U.S. citizens at each tier of ownership, per 46 U.S.C. §50501. For corporations, the CEO and board chairman must also be U.S. citizens.
Licensed officers (master, chief engineer, watch officers) must be U.S. citizens per 46 U.S.C. §8103(a). For unlicensed crew, no more than 25% may be lawful permanent residents. Note: the crewing requirement derives from U.S. vessel documentation law, not the Jones Act itself.
Administrative waivers are authorized under 46 U.S.C. §501 and come in two forms. Under §501(a), at the request of the Secretary of War, DHS may grant a waiver if the Secretary of War considers it "necessary in the interest of national defense to address an immediate adverse effect on military operations." Under §501(b), DHS may waive the Jones Act if the President determines it is "necessary in the interest of national defense," following a determination by the Maritime Administrator of the non-availability of coastwise-qualified vessels to meet national defense requirements. §501(b) waivers are granted on a single-vessel, time-limited basis. The 2026 Operation Epic Fury waiver was issued under §501(a), covering 659 product categories for a 60-day period across all U.S. ports.
This tracker is updated periodically. The snapshot date is displayed prominently on each page.
For questions about the data or methodology, or to report a vessel status that appears incorrect, this site is maintained as a companion resource to maritime policy research at the Cato Institute.