Operation Linebacker: The Sea-Power Factor

On the dark night of 27 August 1972, the Seventh Fleet heavy cruiser USS Newport News (CA-148), light cruiser Providence (CLG-6), guided-missile destroyer Robison (DDG-12), and destroyer Rowan (DD-782) headed for the open waters of the Gulf of Tonkin after bombarding targets around Haiphong, North Vietnam’s major port.

Suddenly, the ships’ surface search radars picked up contacts moving swiftly among the jagged rock outcroppings of Bach Long Vi (Grand Norway Island) southeast of Ha Long Bay. When the approaching fast-attack craft were confirmed as North Vietnamese Soviet-made P-6 torpedo boats, the U.S. task force opened fire. The need to steer clear of the rocks and shoals soon made it difficult for the ships to navigate while at the same time training their guns on the attacking boats cloaked in darkness and cluttered radar returns.

Vice Admiral James L. Holloway III, the Seventh Fleet commander, sailed with the Newport News that night as an observer. Another officer commanded Operation Lion’s Den (the name given to the mission at hand). But when it became obvious that the U.S. ships were having trouble tracking the hostile boats and bringing fire against them, Holloway, a decorated combat veteran of three wars, did not hesitate stepping in to help. He put out a call on an open communications channel: “This is Jehovah (his Commander Seventh Fleet radio call sign).”¹ He requested the assistance of any planes in the area that could illuminate the battle scene with flares.

Flight leader Lieutenant (junior grade) William W. Pikavance and Lieutenant (junior grade) Patrick D. Moneymaker (both of whom later made rear admiral) soon arrived overhead with their A-7 Corsair attack planes and began dropping flares. In short order, the tables had turned on the North Vietnamese assailants, who never got close enough to launch their torpedoes. Cluster bombs dropped by the A-7s and gunfire from the ships sank two of the boats (T-319 and T-349 of Torpedo Boat Squadron 135). Nineteen North Vietnamese officers and enlisted sailors went down with their combat craft in this, the last naval battle of the Vietnam War.

The parting words over the radio of First Lieutenant Cao Hong Tam, the commanding officer of the sinking T-319, were: “Please give our final farewell greetings to our comrades.”²

Taking the Fight North of the 20th Parallel

The U.S. victory at Bach Long Vi was only one example of the Seventh Fleet’s superlative combat performance in the wake of North Vietnam’s Nguyen Hue invasion of South Vietnam (to Americans, the Easter Offensive) that had kicked off on 30 March 1972. Hanoi’s People’s Army of Vietnam (PAVN), armed to the teeth with Soviet-made T-54 battle tanks, PT-76 armored fighting vehicles, 130-mm long-range artillery, and shoulder-fired SA-7 Strela surface-to-air missiles, stormed across the demilitarized zone (DMZ) at the 17th parallel. The objective of Le Duan, Ho Chi Minh’s successor, was to conquer not only South Vietnam’s Military Region I (MR I), but the areas north of Saigon and in the country’s Central Highlands. His ultimate goal was to defeat the Army of Vietnam (ARVN) and end the independence of the Republic of Vietnam.

Enemy forces in MR I quickly overwhelmed the green, understrength 3rd ARVN Infantry Division and pushed on south toward Quang Tri City and the old imperial capital of Hue. Only a small number of U.S. military advisers still served in-country during the last stage of President Richard M. Nixon’s “Vietnamization” program, which was designed to turn the war over to the South Vietnamese as U.S. forces returned to the United States.

Nonetheless, President Nixon was determined to come to the aid of America’s ally and to demonstrate to the leaders of the Soviet Union and the People’s Republic of China that even in the post-Vietnam era, the United States would be a global power to be reckoned with. For Operation Linebacker, the May-to-October interdiction campaign, he ordered the deployment to the combat theater of massive naval and air forces. By 15 May 1972, an unprecedented six aircraft carriers and 95 other warships and support vessels buttressed the naval power of the Seventh Fleet. During the same period, the B-52 strategic bomber forces based on Guam and in Thailand grew to 210 aircraft.

As these resources surged to the western Pacific, the Seventh Fleet’s carrier attack squadrons, cruisers, destroyers, and amphibious ships stepped up to the challenge. These naval forces would prove key to the defeat of the enemy’s Nguyen Hue offensive in MR I. During the first weeks of the attack, a northeast monsoon blanketed the region with heavy clouds and rainfall, limiting the effectiveness of allied air support. The Seventh Fleet immediately deployed destroyers of the Naval Gunfire Support Unit (Task Unit 70.8.9) to the waters off MR I. The USS Buchanan (DDG-14), Waddell (DDG-24), Joseph Strauss (DDG-16), Hamner (DD-718), and eventually as many as 20 warships poured heavy fire into the enemy formations advancing along the main north-south route, QL 1.

In this geographically narrow region of Vietnam, the destroyers’ 5-inch/54-caliber guns could hit targets 12 miles from the sea. U.S. Marine adviser Captain John Ripley, who earned the Navy Cross for his incredibly brave destruction of a vital bridge over the Cua Viet River, credited accurate and timely naval gunfire for savaging the enemy’s road-bound mechanized forces. By 19 May, Seventh Fleet surface ships had fired more than 83,000 rounds in support of the hard-fighting South Vietnamese ground troops.

With the return of good weather during the third week of April, allied air power added to the enemy’s woes. Attack squadrons from the USS Coral Sea (CVA-43), Hancock (CVA-19), and Kitty Hawk (CVA-63) made the enemy pay heavily for their seizure on 1 May of Quang Tri and then helped ARVN forces stabilize a front line along the My Chanh River, just south of the city. The carrier squadrons executed more than 2,000 tactical air strikes, and the U.S. Air Force 1,900, during this critical early period.

Nixon concluded that because of Hanoi’s brazen aggression, President Lyndon B. Johnson’s October 1968 prohibition against U.S. combat operations in North Vietnam was now moot. On 5 April, in Operation Freedom Train, Nixon unleashed U.S. air and naval power against targets in the North Vietnamese panhandle south of the 19th parallel. As they had in South Vietnam, Seventh Fleet cruisers and destroyers operating along the North Vietnamese coast bombarded enemy surface-to-air and antiaircraft sites, road traffic, bridges, and “WIBLICs” (waterborne logistics craft) trying to move supplies southward along the coast.

On 14 April, Admiral Thomas H. Moorer, Chairman of the Joint Chiefs of Staff, authorized the Navy’s cruisers and destroyers to bombard military targets north of the 20th parallel. President Johnson and Secretary of Defense Robert McNamara had severely limited the ability of the fleet’s surface warships to strike targets afloat and ashore, and then only those far from Haiphong. Moorer, however, knew that Nixon had decided to “take out the whole goddamn [Haiphong] dock area, [foreign] ships or no ships.”³

On the 16th, the USS Oklahoma City (CLG-5) and four destroyers, in conjunction with carrier squadrons, hit petroleum storage targets and coastal and antiaircraft defenses in and around Haiphong. The attacks completely obliterated a ship being loaded with supplies for the southern battlefield and severely damaged three combat vessels in the harbor. According to one Vietnamese account, the U.S. warships could operate well beyond the range of coastal defense guns. As a result, “these shelling attacks inflicted serious losses on us without receiving any punishment whatsoever.”⁴

By October, Seventh Fleet warships had bombarded sites around Haiphong five times and by then had fired more than 111,000 rounds that destroyed enemy shore batteries, logistic traffic, and 200 coastal vessels all along the coast.

Enemy coastal batteries routinely traded fire with the fast-maneuvering Seventh Fleet warships, and on occasion their fire killed and wounded American sailors. On 19 April, for instance, an enemy round killed a sailor and wounded seven other crewmen of the destroyer Buchanan. On 23 May, when Vice Admiral Holloway took over the Seventh Fleet on board his flagship, the guided-missile cruiser Oklahoma City, enemy shore-fire straddled the ship but only temporarily delayed the change of command ceremony. The North Vietnamese guns, mostly army field artillery pieces, did not sink a single U.S. warship during the war.

‘Keen on Sinking a U.S. Aircraft Carrier’

Perhaps frustrated by this lack of maritime success, on 19 April Hanoi sent two MiG-17s out to attack the U.S. fleet. The jets swooped down on a task unit that had just finished bombarding Dong Hoi. One of the MiGs dropped a 550-pound bomb on the aft gun of the destroyer USS Higbee (DD-806) that obliterated the unoccupied turret and injured four sailors. For that “victory,” the North Vietnamese paid with the loss of a MiG to a Terrier surface-to-air missile fired by the guided-missile frigate USS Sterett (DLG-31).

Earlier in the war, the North Vietnamese had established a site in Thanh Hoa Province to test the use of their SA-2 air defense weapon as an antiship missile. When U.S. electronic intelligence discovered Hanoi’s intent, carrier aircraft and surface ships ended the experiment in “savage attacks” that leveled the site and rendered the unit there “combat ineffective.”⁵ Hanoi was so keen on sinking a U.S. aircraft carrier that it asked Soviet advisers to train North Vietnamese pilots in “skip bombing.” In that tactic, a jet would approach a ship at low level and skip a bomb across the water and into her hull. When the Soviets turned down the request, the North Vietnamese approached the Cubans. Nothing came of that effort.

According to Soviet Air Force Colonel Isaev Piotr Ivanovitch, who served as an adviser in Vietnam during the war, the Soviets thought the idea so infeasible they wondered if the North Vietnamese were joking. And, despite years of pleading by Hanoi, the Soviets did not provide North Vietnam with Komar-class missile boats armed with Styx antiship missiles until the last weeks of the war, when aircraft from the USS Enterprise (CVAN-65) sank one of the four boats found in Ha Long Bay.⁶

Even as Task Force 77, for the first time since the end of 1965’s Rolling Thunder campaign, returned to the waters off North Vietnam in 1972, other Seventh Fleet forces continued to help the South Vietnamese Army fight off the enemy onslaught in MR I. In what might be called “mini-Inchons,” Marine helicopters of the amphibious task force (Task Force 76) launching from the amphibious assault ship USS Okinawa (LPH-3) airlifted South Vietnamese marines behind enemy lines. Landing craft from the amphibious transport dock Duluth (LPD-6) and other amphibious ships put additional South Vietnamese marines on the beach. In May, June, and July, the U.S.-South Vietnamese amphibious forces launched five major operations and several feints to keep the enemy defenders in MR I off balance and unnerved by attacks from their seaward flank.

In July, the dock landing ship USS Alamo (LSD-33) established a five-section causeway on the beach east of Quang Tri that South Vietnamese forces used to supply their troops inland with ammunition. In September, assisted by allied sea power, the South Vietnamese armed forces liberated Quang Tri City and by the end of the war had secured the fighting front at the Cua Viet.⁷

Vital Vertical Replenishment

It would have been impossible to keep the 100 warships operating continuously off Vietnam without assistance from the Seventh Fleet’s Logistic Support Force (Task Force 73). This vital component provided the fleet with fuel, ammunition, supplies, repair parts, and things such as morale-boosting movies. Routinely, the logistic support force strengthened the fleet with 70 to 97 percent of its requirements for fuel, ammunition, and supplies.

The provision of warships at sea, or underway replenishment, was improved by the Vietnam War innovation of “vertical replenishment,” in which CH-46 Sea Knight helicopters used slings and cargo nets to deposit supplies directly onto the fantails of ships underway.   

In addition to carrier air attack and surface ship bombardment, the Seventh Fleet hit North Vietnam with another of its offensive assets—mine warfare. Between 0859 and 0901 on 9 May, six Navy A-7 Corsairs and three Marine A-6 Intruders flying from the Coral Sea seeded the approaches to Haiphong with 36 Mk-52 magnetic sea mines. This brilliantly conceived and expertly run operation shut down this major port, through which passed 85 percent of Hanoi’s imports, for the rest of the war. No longer would Soviet freighters brazenly steam through the Seventh Fleet area of operations loaded with military hardware for North Vietnam. Hence, in only a few minutes and without cost, the Navy completed an essential mission that Washington had failed to order since 1965.

In the following days and months, as part of Operation Pocket Money, fleet aircraft sowed 11,700 more Mk-52 and Mk-36 Destructors in North Vietnam’s other ports, key river mouths, and coastal areas. Seventh Fleet units, including Marine helicopter gunships, frustrated North Vietnamese efforts to use small vessels to lighter cargo ashore from ships beyond the mined waters. The mining offensive severely impacted Hanoi’s supply situation, especially limiting the import of SA-2 surface-to-air missiles, and put heavy pressure on the rail and road routes from China. Exports from China to North Vietnam during Linebacker fell from 160,000 tons a month to just 30,000 tons.⁸

The Moorer-Zumwalt Historical Debate

As the old expression goes, victory has many fathers, and a good example of that is the question of who was the greatest champion of the Haiphong mining—Admiral Thomas H. Moorer, Chairman of the Joint Chiefs of Staff, or Admiral Elmo R. Zumwalt Jr., Chief of Naval Operations.

Moorer had served in World War II on a Royal Navy mine warfare staff, and he had worked on the aerial minelaying aspects of the Strategic Bombing Survey after the war. As Commander Seventh Fleet; Commander in Chief, Pacific Fleet; and Chief of Naval Operations, Moorer had vigorously pressed for mining North Vietnam. Ergo, he wholeheartedly endorsed Nixon’s decision to do it. Moreover, from that point on he took sole credit for the Haiphong mining. The admiral’s devoted subordinate, Vice Admiral Jerome King, said that Moorer “planned the whole thing.” In Moorer’s multivolume oral history and a contracted think-tank study of the operation, there is no mention of Zumwalt’s involvement.⁹

Zumwalt, however, had long called for the mining of North Vietnam as well, and his mine warfare staff in the Office of the Chief of Naval Operations had all the previous plans on the shelf. Zumwalt related that he and Moorer had worked on a daily basis for weeks to craft the Haiphong plan. Lieutenant Commander (later Rear Admiral) Roberta Hazard remembered seeing Moorer and Zumwalt on their hands and knees on the floor of Zumwalt’s Pentagon office poring over relevant charts. This was one of the few instances, however, when Zumwalt was able as a member of the Joint Chiefs of Staff to have some impact on the strategy and conduct of the war. The President relied almost exclusively on Moorer for military advice, and he had an axe to grind with some of the Joint Chiefs, including the former Military Assistance Command, Vietnam, Generals William Westmoreland and Creighton Abrams. Moreover, Nixon considered Zumwalt a radical social reformer whom he thought was ruining the Navy he had served in during World War II.

MiG-Busters

In a demonstration of the fleet’s enhanced capability in 1972, on the morning of the mining operation, the guided-missile cruiser USS Chicago (CG-11), positioned 30 miles southeast of Haiphong, shot down with a Talos missile one of three MiGs that dared approach the mining planes. The surviving aircraft quickly turned tail. And that same morning, as a diversion, the destroyers Buchanan, Richard S. Edwards (DD-950), and Myles C. Fox (DD-829) boldly closed with the coast near the Do Son light and bombarded enemy antiaircraft sites.

The fleet unleashed even more devastating firepower on 10 May, the first day of the Linebacker campaign, the object of which was to limit Hanoi’s ability to wage war. On three separate occasions that day, multi-plane strikes from the Coral Sea, Kitty Hawk, and Constellation (CVA-64) hit bridge, rail, road, and other targets around Haiphong, Hai Duong, and Hon Gai/Cam Pha. Simultaneously, Air Force squadrons bombarded the Long Bien (Paul Doumer) highway bridge near Hanoi and the Yen Vien rail yard.

North Vietnam’s leaders were so concerned about these attacks in their nation’s heartland that they dispatched their MiG force to meet the American squadrons. That action would cost them dearly. Between 1300 and 1306, Navy F-4 Phantoms shot down six of the 11 North Vietnamese MiGs that Navy and Air Force fighters would claim that day. One author with access to North Vietnamese records has observed that for the 923rd Fighter Squadron that operated MiG-17s, “May 1972 proved to be the worst month of the entire war.”¹⁰

On 10 May, F-4 pilot Lieutenant Randy Cunningham and his radar intercept officer Lieutenant (junior grade) William Driscoll became the war’s first aces when they achieved the last of their five aerial victories. Both men had benefited from training in air-to-air combat at the Navy’s “Top Gun School,” established to improve the Navy’s poor 2-to-1 ratio of wins to losses during Rolling Thunder. In 1972, the carrier squadrons registered a 13-to-1 ratio.    

Another key to many of the successes of the Navy and Air Force fighters was the assistance provided them from the guided-missile cruisers posted to the PIRAZ (positive identification radar advisory zone) station southeast of Haiphong. Throughout the war, the ships at this station, which used the call sign “Red Crown,” boasted the Navy’s most advanced radar and communication systems and highly trained personnel. As one example of their prowess, the Chicago’s Senior Chief Radarman Larry Nowell earned a Navy Distinguished Service Medal for helping guide Navy and Air Force fighters in the destruction of 12 MiGs.¹¹

The Seventh Fleet’s carrier strikes during Linebacker benefited from a weapon system that had been in its infancy during Rolling Thunder—the precision-guided munition (PGM). From the outset of the bombing campaign, the Navy employed the AGM-62A Walleye TV-guided bomb, nicknamed “Fat Albert,” and the Air Force its laser-guided bomb, to take out all but a few of the bridges in North Vietnam, particularly those between the Tonkin Delta and China.

An especially notable mission occurred on 6 October when four Attack Squadron 82 A-7E Corsairs (one piloted by future four-star Admiral Leighton W. “Snuffy” Smith) attacked the Thanh Hoa (Dragon’s Jaw) Bridge, which had withstood many previous attempts to permanently sever this critical transportation node. In the 6 October attack, Smith and his wingman, Lieutenant (junior grade) Marvin Baldwin, put two Walleyes, and the other A-7s several conventional bombs, on the target that, with follow-on missions, put the bridge out of action for the rest of the war.¹²

The Linebacker campaign reached a peak for the Seventh Fleet in late summer 1972, when Task Force 77 aircraft were executing as many as 4,700 attack sorties a month. Negotiations to end the war, however, broke down at the end of October. Nixon then decided to up the ante with a massive B-52 bomber and tactical air assault on North Vietnam. He told Moorer that “this is your chance to use military power effectively to win this war, and if you don’t, I’ll consider you responsible.”¹³ Energized by this call to action, the Joint Chiefs chairman designed a campaign to inflict maximum damage on the enemy’s war-making capability and convince the leaders and population of North Vietnam that Nixon meant business. Beginning on 18 December, as waves of B-52s hit targets in and around Hanoi, Seventh Fleet forces added their power to the Linebacker II campaign. The USS Midway (CVA-41), America (CVA-66), and Ranger (CVA-61) attack squadrons focused their strikes on Haiphong as Seventh Fleet surface cruisers and destroyers pummeled military targets in 24-hour operations all along the coast and inland. On 28 December, after a “maximum effort” B-52 bombing raid on Hanoi, the North Vietnamese finally agreed to meet to end the war. That gathering produced the Paris Agreement of 27 January 1973.

The Navy’s Crucial Role in Ending the War

In short, sea power proved vital to the allied defeat of North Vietnam’s Nguyen Hue Offensive of 1972 and to the effort to bring Hanoi to the peace table. In the strategic realm, U.S. sea power enabled President Nixon to support South Vietnam’s fight for survival and to make it clear to the Soviet Union and the People’s Republic of China that U.S. global reach and military power would continue to be relevant in the post-Vietnam era.

The Seventh Fleet made the most significant operational contributions to allied success in five areas:

1. Air Operations: The U.S. Navy and Air Force bombing campaigns were essential to defeat of the Nguyen Hue offensive in South Vietnam; they seriously degraded North Vietnam’s air and coastal defenses and put heavy military and psychological pressure on Hanoi to negotiate an end to the fighting.

2. Mining Operations: The Seventh Fleet’s mining campaign closed off North Vietnam’s access to seaborne imports of war materials, increased the difficulty of moving supplies southward along the coast, and enabled a bombing concentration on the enemy’s rail and road supply lines from China.

3. Defeat of the Nguyen Hue Offensive in South Vietnam’s Military Region I: The Seventh Fleet’s cruiser-destroyer, amphibious, and carrier forces enabled the South Vietnamese marine and ARVN forces to blunt the enemy drive on Hue and then execute an allied counterattack that liberated Quang Tri City.

4. Naval bombardment of North Vietnam: The fleet’s cruisers and destroyers added to the heavy pressure on the enemy’s logistical movements along North Vietnam’s southern panhandle and brought unprecedented naval power to bear on the critical defensive and logistical infrastructure around Haiphong.

5. Neutralization of North Vietnam’s Navy: Through the sinking of enemy P-4 and P-6 torpedo boats and other combatants at sea, along the coast, and in port, the Task Force 77 carrier squadrons and surface warships eliminated the enemy’s maritime threat to the fleet.

While focused on the success of air power during Linebacker II, Admiral Moorer would have had no trouble including sea power in the equation when he observed that “airpower, given its day in court after almost a decade of frustration, confirmed its effectiveness as an instrument of national power.”¹⁴