Throughout history, two categories of ships, merchants and naval combatants, have carried out the world's seagoing activities. Those of the merchant marine, known as merchantmen, carry cargo, passengers, and perform special functions during times of war. Navies have the mission of maintaining sea lanes to enable the nation's merchant marine to move freely and safely and to prevent an enemy from doing so. In times of war, the distinction between merchantmen and fighting ships can be narrow.
The selfless sacrifice of American merchant marines to the defense, commerce and growth of this nation date back to the independence of the United States. The first Congress established "Shipping Articles" providing the foundation upon which United States Merchant Marine was founded. American merchantmen brought goods and gold seekers to California from around the world and helped establish and maintain a maritime presence on Sacramento's riverfront lasting into the late 1960's. The United States Merchant Marine Academy is at Kings Point, New York. The California Maritime Academy is located near the mouth of the Sacramento River at Vallejo.