• The U.S. 7th Fleet sent carrier planes to support American forces in South Vietnam and to attack designated targets in North Vietnam. Fleet warships supporting operations near the coast occasionally used their big guns. The largest gun, shown here on the battleship New Jersey in October 1968, fired 16-inch shells. The war’s most notable naval gun was the technologically advanced 5-inch/54-caliber Mark 42, introduced in 1953. The enemy seldom endangered American warships; however, on April 19, 1972, two MiG-17s attacked the fleet. Pilot Nguyen Van Bay dropped two bombs that nearly hit the light cruiser Oklahoma City, causing slight damage, while Le Xuan Di dropped one bomb on destroyer Higbee, knocking out a 5-inch gun turret and wounding four men. The destroyer Sterrett claimed to have downed one of the MiGs with an air-to-air missile, but, in fact, both Vietnamese pilots returned unscathed. (Neil Leifer/Sports Illustrated/Getty Images)
  • In 1965, the U.S. Navy, U.S. Coast Guard and South Vietnamese navy launched Operation Market Time, a concerted effort to disrupt Communist coastal and riverine traffic. Vietnam’s many rivers and swamps spurred the rapid development of specialized small water craft. (U.S. Navy)
  • The “patrol craft, fast” or “swift boat." (Getty Images)
  • The radical “patrol air cushion craft,” with almost amphibious capabilities at speeds of 45-60 mph. (Getty Images)
  • The "SEAL team assault boat,” in January 1969. SEAL teams emerged from the war as one of the most elite units of the U.S. military. (U.S. Navy)
  • The primary role of North Vietnam’s navy was guarding the coast to counter South Vietnamese commando raids, but in a more aggressive move three of its Soviet-designed, Chinese-built P4 class torpedo boats, like those at right, attacked the U.S. destroyer Maddox in the Gulf of Tonkin on Aug. 2, 1964. The Maddox and F-8 Crusaders from carrier USS Ticonderoga damaged and drove off the assailants. The clash revealed the inadequacies of North Vietnam’s torpedo boats, and the U.S. used the incident to expand its military presence in the country. (Sputnik/Alamy)
  • The backbone of Viet Cong riverine operations was the simple sampan, below, which relied on stealth rather than technology in hostile waters. (Getty Images)
From the Gulf of Tonkin to the Mekong Delta, new technologies were launched during the Vietnam War.

Vietnam has hundreds of miles of irregular coastline, along which the enemy spirited boatloads of  men and supplies to supplement troops moving overland on the Ho Chi Minh Trail. Meanwhile, Viet Cong vessels plied the Mekong Delta, where they encountered U.S. and South Vietnamese riverine forces patrolling the delta.

Perhaps the most significant legacy of the naval war was the creation of U.S. Navy SEAL (sea-air-land) teams in January 1962. Using members of underwater demolition teams, the SEALs expanded the UDT’s combat roles and honed their skills to the fine edge that they have demonstrated ever since.

The Viet Cong occasionally conducted their own waterborne commando operations. In May 1966, they laid a mine to sink the supply ship Eastern Mariner in Nha Be anchorage and in August used a remotely detonated mine to severely damage Baton Rouge Victory in the Long Tau River, both near Saigon.

In Operation Pocket Money, launched on May 9, 1972, the 7th Fleet laid 11,000 mines to block the North Vietnamese from maritime trade. After the signing of the Paris Peace Accords on Jan. 27, 1973, the Navy spent five months clearing those shipping lanes in Operation End Sweep.