Battle of the Mỹ Chánh Line

Battle of the Mỹ Chánh Line
Part of Easter Offensive of the Vietnam War
South Vietnamese outpost on the Mỹ Chánh Line, May 1972
Date 5 May to 26 June 1972 Location northwest of Huế, South Vietnam 16°37′55″N 107°18′11″E / 16.632°N 107.303°E / 16.632; 107.303 Result Allied military victory
Belligerents
South Vietnam  United States	North Vietnam
Commanders and leaders
Ngô Quang Trưởng Frederick Kroesen Edward J. Miller
Units involved
Marine Division 1st Division Airborne Division 9th Marine Amphibious Brigade	325th Division
Casualties and losses
764+ killed	ARVN claimed: 3661+ killed 70+ armored vehicles destroyed

The Battle of the Mỹ Chánh Line took place from 5 May to 26 June 1972 during the

Background

At the end of the

On 4 May, the South Vietnamese Joint General Staff replaced the ineffective General Hoàng Xuân Lãm as I Corps commander with Lieutenant General Ngô Quang Trưởng. Trưởng moved his main command post to the Huế Citadel, a move that reflected a change in purpose and focus for operations in Military Region I (MR I). His immediate task was to stabilize his forces and to make effective use of available American support through 1st Regional Assistance Command (FRAC) which had replaced the United States Army's XXIV Corps. On the same date, President Nguyễn Văn Thiệu announced the appointment of Colonel Bui The Lan, as interim VNMC commander. Thiệu's order of the day was that the Mỹ Chánh Line would hold; there would be no further withdrawals.^[2]: 92

Trưởng's available forces initially included elements of the VNMC north and northwest of Huế, the

As the PAVN offensive halted at the Mỹ Chánh River, everything to the north was declared a free-fire zone. FRAC believed that the PAVN were capable of launching a new offensive in Thừa Thiên Province as the 304th, 308th and 324B Divisions, the 202nd and 203rd Armored Regiments and supporting units were all available for an assault. From 5 to 25 May, the PAVN probed the river-edge defenses. Losses sustained in the previous weeks did not permit full-scale offensive actions, but the PAVN's intentions were clear. Huế was the target and a major assault of the Mỹ Chánh Line was imminent.^{[2]: 92–4}

Battle

On 5 May, the Marine 258th Brigade displaced its headquarters north from Huế to

After having overrun Firebase Bastogne and Firebase Checkmate at the end of April, on 5 May the PAVN 324B Division attempted to continue their advance down Route 547 towards Huế and in two clashes 2 miles (3.2 km) west and southwest of Firebase Birmingham, 39 PAVN and two ARVN were killed.^[5]

On 8 May the

The two landing zones received devastating fire from the air and sea. As a result, touchdown in Landing Zone Tango (16°42′25″N 107°16′05″E / 16.707°N 107.268°E / 16.707; 107.268) occurred at 09:30 without opposition in a cloud of dust and smoke. The Marine helicopters returned to the ships for fuel then flew back to Firebase Sally for the second wave at 10:55. As the lead aircraft touched down in Landing Zone Delta moderate small-arms fire was received. Immediately, the Army commander of the escorting gunships shifted the landing to the southern portion of the zone. The PAVN hit three CH-46s and Marine airmen left one CH-53 in the zone with a damaged tail rotor which had to be destroyed to prevent its capture.^[2]: 96

Once on the ground, the two battalions swept south and attacked toward the Mỹ Chánh River. Shortly thereafter, the 9th Battalion crossed the Mỹ Chánh and attacked north toward its two sister battalions. The PAVN 66th Regiment was caught completely by surprise. As the two battalions marched south to link up with the 9th Battalion, they uncovered large quantities of combat equipment and freed more than 150 civilians who had been detained by the PAVN. The joint efforts resulted in reports of 240 PAVN soldiers killed, three tanks destroyed and two 130mm guns put out of action.^{[2]: 96–7 [3]: 57 [1]: 304}

On 14 May approximately 4,000 ARVN 1st Division troops supported by artillery and B-52 strikes advanced west from Firebase Birmingham along Route 547 coming to within 0.5 miles (0.80 km) of Firebase Bastogne and killed 110 PAVN.^[6]

PAVN attack 21–2 May

On 21 May the PAVN mounted a full-scale armor and infantry attack on the Mỹ Chánh Line in an attempt to regain the initiative. The PAVN attacked due south down the coastal highway, Route 555, (16°42′22″N 107°21′36″E / 16.706°N 107.36°E / 16.706; 107.36) moved across the Mỹ Chánh River and penetrated the 369th Brigade's defensive area. The Regional Force troops fell back, exposing the flanks of the 3rd and 9th Battalions. Vulnerable to the overwhelming armor threat, both battalions withdrew. After an all-day fight, however, the two battalions, assisted by close air strikes and ARVN armored cavalry, began pushing the PAVN back towards the Mỹ Chánh River. The Marines had suffered heavy casualties but by nightfall had largely restored the line.^{[2]: 97–8}

The PAVN remained determined to gain a foothold on the south bank of the river. At 01:00 on 22 May, the PAVN launched a tank-infantry attack against the 3rd Battalion. They had the initiative and the numerically superior force, supported by 25 tanks, overran the forward battalion, but not before the Marines had destroyed eight tanks with M72 LAWs and direct fire from 105mm howitzers. Continuing their attack through the early morning darkness, the PAVN penetrated deeply into South Vietnamese territory, hitting the 369th Brigade's command post at first light. A U.S. Army sergeant fired the BGM-71 TOW missile system from atop the command and control center bunker destroying a PT-76 and then a heavy machine gun nest. Five PAVN armored vehicles came within 400 meters of the command post before being destroyed. By 09:30, a total of 10 tanks and armored personnel carriers had been destroyed. As the 8th Battalion counterattacked, the PAVN fled the battlefield, leaving their dead and wounded.^{[2]: 98 [3]: 57 [1]: 304}

Operation Song Than 6-72

On 23 May, the 7th Battalion and its advisors moved by truck to Tân Mỹ Base where it boarded landing craft for the short trip to the ships of the U.S. amphibious force: the USS Schenectady, USS Manitowoc, USS Cayuga and USS Duluth in preparation for Operation Song Than 6-72 an amphibious assault at Wunder Beach 10 km north of the Mỹ Chánh Line and a heliborne assault 6 km inland. The operation was coordinated onboard USS Blue Ridge by the 147th Brigade and 9th MAB staff.^[2]: 98 The USS Anchorage (LSD-36) was present, I was on it and we did take shots fired from Beach, But Destoryer fired at them and no more was hear, Cp. Danny Holden, USMC

The landing began the next morning, 24 May, with artillery, air, and naval gunfire strikes on Wunder Beach and Landing Zone Columbus (16°44′38″N 107°18′14″E / 16.744°N 107.304°E / 16.744; 107.304) near Quảng Trị at the road junction of Routes 555 and 602. Lifting off the USS Okinawa at 07:50, the helicopters of HMM-164 headed towards Tân Mỹ to pick up the Marine assault troops. Loading some 550 Marines from the 4th and 6th Battalions, the helicopters took off for their objective. The assault ships launched 20 LVTP-5 amphibian tractors, with USMC crews and VNMC assault troops, from a release point 3,600 yards (3,300 m) off Wunder Beach. The LVTPs formed into two waves, as they closed within 2,000 yards (1,800 m) of Red Beach a final B-52 strike placed a string of bombs down the length of the beach, raising a curtain of fire and sand. The LVTPs hit the beach at 08:32 and were met by scattered PAVN infantry and artillery fire.^{[2]: 99–100}

As the Marines consolidated and moved off the beach behind continuing air support and naval gunfire, the USMC amphibian tractors returned to the ships. It was the first combat experience for 90% of the Americans involved. While launching the surface assault, the Duluth and the Cayuga were fired upon by a PAVN artillery battery. The destroyer USS Hanson and other gunfire support ships returned fire and silenced the PAVN battery. Initial reports from the landing force indicated that the 7th Battalion had secured its immediate objectives, killing at least 50 PAVN troops in the process. As they quickly moved over the sand dunes to the south, the Marines encountered only token resistance from the surprised enemy. Later field messages reported large amounts of weapons, ammunition and food caches captured.^[2]: 100

At 09:40, 18 CH-46 and CH-53 helicopters from HMM-164 lifted elements of the 4th and 6th Battalions into Landing Zone Columbus. Artillery smoke was laid west of LZ Columbus to screen the helicopter movement from enemy artillery fire and the Army air-cavalry division gunships marked the zone with suppressive fires. No enemy fire was encountered by the helicopters as the Marines unloaded. Soon after landing, however, both battalions made heavy contact with elements of the 18th Regiment, 325th Division. Two PAVN soldiers captured by the Marines stated that their regiment had just arrived in the area in preparation for an attack on the Mỹ Chánh Line.^[2]: 100

All the battalions of 147th Brigade returned to the Mỹ Chánh Line, terminating the second offensive action by the VNMC. In addition to the two prisoners of war, 369 PAVN were claimed killed, three tanks were destroyed and more than 1,000 civilians were freed from PAVN control.^[2]: 100

PAVN attack 25 May

As air observers and FACs uncovered road and trail networks or spotted troop movements and vehicles, they would report them to the Marine defenders along the Mỹ Chánh Line. As trails, supply points, and troop sightings were plotted and connected, a pattern soon developed showing lines of communication mainly from the Ba Long Valley towards Camp Evans. With the arrival of the 325th Division in Quảng Trị Province, the PAVN had three divisions with which to attack the Mỹ Chánh Line.^{[2]: 101–2}

At 05:30 on 25 May, a numerically superior PAVN tank-infantry force hit the 258th Brigade in the western portion of the Marine division's large area of responsibility. The regimental-size enemy force made a stubborn attempt to break through the Mỹ Chánh Line. Although armor was employed in unprecedented numbers, the PAVN committed its infantry prematurely, exposing it to heavy supporting arms fire.^{[2]: 100–1}

Early on the morning of 26 May, a reinforced PAVN battalion launched an attack against the 258th Brigade's western flank. One element of the PAVN force made the 9th Battalion pull back more than 1,000 meters to consolidate. Heavy air strikes and naval gunfire was directed onto the attackers, who finally broke contact, leaving their dead where they had fallen. The 1st Battalion was also heavily hit by the attack. Two PAVN battalions from the 88th Regiment, supported by tanks, mortars, recoilless rifles and artillery fire, threatened to overrun the 1st Battalion's position. Air strikes were directed on the attackers inflicting many casualties. As the PAVN withdrew they left more than 200 dead on the battlefield. Throughout May along the Mỹ Chánh Line the PAVN had suffered more than 2,900 soldiers killed, 1,080 weapons captured and 64 armored vehicles destroyed or captured.^{[2]: 102–3 [3]: 57–60}

On 31 May President Thiệu promoted Marine Division commander Colonel Bui The Lan to Brigadier General at the

On 8 June the Marines launched a spoiling attack named Song Than 8-72. All three brigades were committed in a four-battalion attack across the river. The Marines moved forward under the cover of a closely coordinated fire support plan which included B-52 strikes, tactical air, artillery and naval gunfire. The American-established FSCC at division headquarters permitted supporting arms to be fired in concert, a technique heretofore fraught with problems of execution.[2]^{: 100–1 [1]: 304}

As the battalions crossed the Mỹ Chánh River, the heaviest resistance was encountered along the coastal areas, particularly along Route 555. The PAVN was well entrenched, but Marine casualties were comparatively light with nine men killed in action. The PAVN took heavy losses, with the operation accounting for 230 PAVN killed, seven tanks destroyed and 102 weapons, including several SA-7 missiles captured or destroyed. At the conclusion of the operation the Marines were north of the Mỹ Chánh River, once again in Quảng Trị Province and anxious to continue north.^{[2]: 103–4}

In order to consolidate the Marines' captured territory, ARVN engineers built pontoon bridges across the Mỹ Chánh River to give tanks, artillery, and trucks access to Quảng Trị Province. Plans were already being made to send the Marine brigades back into the offensive. Such plans culminated in Operation Song Than 8A-72.^[2]: 104

Operation Song Than 8A-72

Beginning on 18 June Operation Song Than 8A-72 again involved all three VNMC brigades. 147th Brigade struck north along Route 555, into the notorious Street Without Joy coastal area. 369th Brigade held the center position as it attacked across open rice paddies, flanked to the west by 258th Brigade, moving along Highway 1. The PAVN forces were defending in depth along Highway 1 and Route 555, reinforced by armor, artillery and antiaircraft units. Stream and canal networks between the two roads were interlaced with trenches and fortified positions. Further to the west lay rolling hills and the PAVN's 130mm guns.^{[2]: 104 [1]: 304}

On the night of 20 June a reinforced PAVN infantry battalion supported by tanks and artillery hit the 6th Battalion, 147th Brigade's night defensive position on Route 555. The tanks were not coordinated with the infantry maneuver and Marine artillery quickly responded to each tank sighting with massed fire. Despite this, at least 40 PAVN soldiers were able to break through the 6th Battalion's perimeter and attack the battalion command post, fragmenting the command group. For the next eight hours the battle raged. Both tactical aircraft and naval gunfire supported the battalion as Lieutenant Colonel Do Huu Tung rallied his battered Marines for a tank and infantry counterattack. Backed by B-52 strikes and other supporting arms, the 6th Battalion pushed the PAVN out. The PAVN responded with heavy artillery and mortar fire throughout the entire zone of action. While the 6th Battalion was fighting for its survival, the 1st and 5th Battalions also repulsed large armored counterattacks.^{[2]: 104–5}

By 27 June, the Marines had successfully established a new defensive line 4 km north of the Mỹ Chánh River. The operation had resulted in 761 PAVN killed, eight tanks destroyed and freed hundreds of captive villagers.^[2]: 105

PAVN attacks 22–4 June

On 22 June the PAVN attacked ARVN Airborne positions 4 miles (6.4 km) southwest of Mỹ Chánh, but the attack was repulsed by the ARVN supported by B-52 strikes. Sixteen tanks were destroyed and 146 PAVN killed for the loss of one ARVN.^[7] On 23 June the PAVN mounted another attack west of Huế which was repulsed with 13 tanks destroyed and 98 PAVN killed for the loss of five ARVN killed.^[8] On 24 June starting at 01:00 with a barrage from 130mm guns the PAVN launched another assault on the line which was repulsed with 22 tanks knocked out and more than 100 PAVN killed by the South Vietnamese Marines. Seven tanks were destroyed by U.S. fighter-bombers while eight were destroyed by U.S. helicopter gunships with BGM-71 TOW anti-armor missiles.^[9]

Aftermath

The probing attacks in June tested PAVN strength and allowed for the establishment of advance positions ahead of the launch of General Trưởng's

The official PAVN history records the battle as follows:[10]

This was a great opportunity, but, because we lacked a reserve force and because we had not prepared roads and supplied beforehand, our troops were not able to take advantage of this opportunity to exploit our victory and liberate Thừa Thiên-Huế...The enemy focussed on consolidating his defensive line along the Mỹ Chánh River and used this line as a base to strike out to the east and west to disrupt our preparations to attack Huế...Our troops experienced many difficulties in maintaining supply levels and we were able to provide only 30 percent of the supplies called for in our plan. In addition, because we had been slow to change our campaign tactics as the enemy strengthened his forces and solidified his defense, our assault against the Mỹ Chánh defensive line from 20 to 26 June was unsuccessful...In late June 1972 the fighting on the Trị-Thiên Front became very complex, with fierce back-and-forth fighting between our troops and the enemy.

References