The United States Merchant MarineMarine is the French word for "navy", and many English-speaking countries call their fleet the Merchant Navy. Similar terms are used are used in other languages: for example, the French Marine Marchande and the Spanish Marina Mercante. refers collectively to U.S.-flagged commercial vessels, both privately and federally owned, and the civilian mariners who crew them. Both the civilian mariners and the merchant vessels are managed by a combination of the government and private sectors, and engage in commerce or transportation of goods and services in and out of the navigable waters of the United States.
The Merchant Marine primarily transports domestic and international cargo and passengers during peacetime, and operates and maintains deep-sea merchant ships, tugboats, towboats, ferries, dredges, excursion vessels, charter boats and other waterborne craft on the oceans, the Great Lakes, rivers, canals, harbors, and other waterways. In times of war, the Merchant Marine can be an auxiliary to the United States Navy, and can be called upon to deliver personnel and materiel for the military.
In the 19th and 20th centuries, laws fundamentally changed American merchant shipping. These laws put an end to common practices such as flogging and shanghaiing, and increased shipboard safety and living standards. The United States Merchant Marine is also governed by more than 25, as of February 2017,The International Maritime Organization (IMO) was first organized as an organ of the United Nations in 1948, but did not come into force until the 27th member (Egypt), of which 7 must have at least 1,000,000 tons of shipping, signed the International Maritime Organization Convention in 1958. There are currently more than 175 Member States, and 55 Conventions and Amendments managed by the IMO. The U.S. is signatory to at least 25 Conventions and Amendments covering maritime safety, pollution, security, search and rescue, and other issues, in addition to U.S. laws and regulations. See: http://www.imo.org/en/About/Conventions/StatusOfConventions/Documents/status-x.xls international conventions to promote safety and prevent pollution.
In 2022, the United States merchant fleet had 178 privately owned, oceangoing, self-propelled vessels of 1,000 gross register tons and above. Nearly 800 American-owned ships are flagged in other nations.In 2006, 264 American ships were registered in the Bahamas and the Marshall Islands, widely considered flag of convenience countries.
The federal government maintains fleets of merchant ships managed by the United States Maritime Administration. In 2014, they employed approximately 6.5% of all American water transportation workers. Merchant Marine officers may also be commissioned as military officers by the Department of Defense. This is commonly achieved by commissioning unlimited tonnage Merchant Marine officers as strategic sealift officers in the United States Navy Reserve.
Shipboard operations
Captains, mates (officers), and pilots supervise ship operations on domestic waterways and the high seas. A captain (master) is in overall command of a vessel, and supervises the work of other officers and crew. A captain has the authority to take the conn from a mate or pilot at any time he or she feels the need. On smaller vessels the captain may be a regular watch-stander, similar to a mate, directly controlling the vessel's position. Captains and department headsTypical departments include the deck department, engine department, and steward's department. ensure that proper procedures and safety practices are followed, ensure that machinery is in good working order, and oversee the loading and discharging of cargo and passengers. Captains directly communicate with the company or command (MSC), and are overall responsible for cargo, various logs, ship's documents, credentials, efforts at controlling pollution and passengers carried.
Mates direct a ship's routine operation for the captain during work shifts, which are called watches. Mates stand watch for specified periods, usually in three duty sections, with four hours on watch and eight hours off.On smaller vessels, there may be only one mate (called a pilot on some inland towing vessels), who alternates watches with the captain. The mate would assume command of the ship if the captain became incapacitated. When on a navigational watch, mates direct a bridge team by conning, directing courses through the helmsman and speed through the lee helmsman (or directly in open ocean). When more than one mate is necessary aboard a ship, they typically are designated chief mate or first mate, second mate and third mate.
In addition to watch standers, mates directly supervise the ship's crew, and are assigned other tasks. The chief mate is usually in charge of cargo, stability and the deck crew, the second mate in charge of navigation plans and updates and the third mate as the safety officer. They also monitor and direct deck crew operations, such as directing line handlers during moorings, and anchorings, monitor cargo operations and supervise crew members engaged in maintenance and the vessel's upkeep.
Harbor pilots guide ships in and out of confined waterways, such as harbors, where a familiarity with local conditions is of prime importance.On river and canal vessels, pilots are usually regular crew members, like mates. Harbor pilots are generally independent contractors who accompany vessels while they enter or leave port, and may pilot many ships in a single day.
Engine officers, or engineers, operate, maintain, and repair engines, boilers, generators, pumps, and other machinery. Merchant marine vessels usually have four engine officers: a chief engineer and a first, second, and third assistant engineer. On many ships, Assistant Engineers stand periodic watches, overseeing the safe operation of engines and other machinery. However, most modern ships sailing today utilize unmanned machinery space (UMS) automation technology, and Assistant Engineers are dayworkers. At night and during meals and breaks, the engine room is unmanned and machinery alarms are answered by the Duty Engineer.
Marine oilers and more experienced qualified members of the engine department, or QMEDs, maintain the vessel in proper running order in the engine spaces below decks, under the direction of the ship's engine officers. These workers lubricate gears, shafts, bearings, and other moving parts of engines and motors; read pressure and temperature gauges, record data and sometimes assist with repairs and adjust machinery. Wipers are the entry-level workers in the engine room, holding a position similar to that of ordinary seamen of the deck crew. They clean and paint the engine room and its equipment and assist the others in maintenance and repair work. With more experience, they become oilers and firemen.
Able seamen and ordinary seamen operate the vessel and its deck equipment under officer supervision and keep their assigned areas in good order.On inland waters, able seamen may simply be called "deckhands." They watch for other vessels and obstructions in the ship's path, as well as for navigational aids such as buoys and lighthouses. They also steer the ship, measure water depth in shallow water, and maintain and operate deck equipment such as lifeboats, anchors, and cargo-handling gear.
On tankers, mariners designated as pumpmen hook up hoses, operate pumps, and clean tanks. When arriving at or leaving a dock, they handle the mooring lines. Seamen also perform routine maintenance chores, such as repairing lines, chipping rust, and painting and cleaning decks. On larger vessels, a boatswain—or head seaman—will supervise the work.
As of 2011, a typical deep-sea merchant ship has a captain, three mates, a chief engineer and three assistant engineers, plus six or more unlicensed seamen, such as able seamen, oilers, QMEDs, and cooks or food handlers known as stewards.The size and service of the ship determine the number of crewmembers for a particular voyage. Other unlicensed positions on a large ship may include electricians and machinery mechanics.Small vessels operating in harbors, on rivers, or along the coast may have a crew comprising only a captain and one deckhand. The cooking responsibilities usually fall under the deckhands' duties. On larger coastal ships, the crew may include a captain, a mate or pilot, an engineer, and seven or eight seamen. Some ships may have special unlicensed positions for entry level apprentice trainees.
History
The North American shipping industry developed as colonies grew and trade with Europe increased. As early as the 16th century, Europeans were shipping horses, cattle and hogs to the Americas.
Spanish colonies began to form as early as 1565 in places like St. Augustine, Florida, and later in Santa Fe, New Mexico; San Antonio, Tucson, San Diego, Los Angeles and San Francisco. English colonies like Jamestown began to form as early as 1607. The connection between the American colonies and Europe, with shipping as its only conduit, would continue to grow unhindered for almost two hundred years.
Revolutionary War
The first wartime role of an identifiable United States Merchant Marine took place on June 12, 1775, at the Battle of Machias. A group of Machias residents, hearing the news of the Battles of Lexington and Concord, captured the British supply sloop HMS Margaretta. Word of the capture reached Boston, where the Continental Congress and the various colonies issued letters of marque to American privateers. The privateers interrupted British supply chains along the eastern seaboard of the United States and across the Atlantic Ocean. These actions by the privateers predate both the United States Coast Guard and the United States Navy, which were formed in 1790 and 1797, respectively.
Early Republic
During the Napoleonic Wars the American carriers, particularly in New England, were the neutral parties that benefited economically during these years.Sterns, Worthy P. “The Foreign Trade of the United States From 1820 to 1840.” Journal of Political Economy, vol. 8, no. 1, 1899, pp. 34–57. JSTOR website Retrieved 4 June 2025.
19th and 20th centuries
The merchant marine was active in subsequent wars, from the Confederate commerce raiders of the American Civil War, to the assaults on Allied commerce in the First and in the Second World Wars. 3.1 million tons of merchant ships were lost in World War II. Mariners died at a rate of 1 in 26, which was the highest death rate of any service.. All told, 733 American cargo ships were lost and 8,651 of the 215,000 who served perished in troubled waters and off enemy shores.
During World War II, ships with deck guns had United States Navy Armed Guard to man the guns. Some Armed Guard personnel also served as Radiomen and Signalmen. The Navy gun crews were assisted by ship's crew, though the merchant mariner's training in gunnery and combat role was ignored for years. Specific instructions as to merchant crew manning of guns and training they should receive was issued by the War Shipping Administration which operated all U.S. merchant ships either directly or through agents during the war. By the wars end, 144,857 men had served in the Navy Armed Guard, on 6,200 ships.
Merchant shipping played its role in the wars in Vietnam and Korea. During the Korean War, under the operational control in theater of the Military Sea Transportation Service (MSTS), the number of chartered ships grew from 6 to 255. In September 1950, when the U.S. Marine Corps went ashore at Incheon, 13 Navy cargo ships, 26 chartered American, and 34 Japanese-manned merchant ships of the MSTS participated.