Comrade Giap’s Clever Nuggets #8: Siege of Khe Sanh

Campaign Series Vietnam | Comrade Giap's Clever Nuggets

Comrade Giap's Clever Nuggets is yet another series, where David Galster shares some of his tips and techniques in scenario research and design for CS: Vietnam.

Comrades,

Can you recall the important battle, in a different war, that is often compared to Khe Sanh?

If you guessed Dien Bien Phu, your intuition is correct. This article describes the siege, its outcome, and gives an analysis of why it is compared to Dien Bien Phu, and what the differences were.

Intelligence Tips

Fortunately for MACV, there were some warning signs prior to the Khe Sanh attacks on 20 January 1968. During the last three months of 1967, the CIA and MACV G2s noted increased traffic on the Ho Chi Minh trail. Aerial reconnaissance also noted stockpiling of supplies at Mu Gia pass. Heavy truck traffic was observed on route 912, a main road from North Vietnam into Laos. On 20 December 1967, Westmoreland cabled Washington that he expected the Viet Cong and North Vietnamese "to undertake an intensified countrywide effort, perhaps a maximum effort, over a relatively short period of time."

Truck sightings were the evidence of increased Ho Chi Minh trail activity. In the first nine months of 1967, the monthly average was 480 sightings. This surged to 1116 in October, 3823 in November, and 6315 in December. This is in contrast to 256 truck sightings/month in late 1966.

The NVA/VC stepped up attacks on Loc Ninh in the III CTZ area. This was believed to be a prelude to larger dry season attacks, and possibly an attempt to establish another "front" in areas adjacent to Cambodia. The timing coincided with tough statements made by Le Duan in Moscow about future negotiations.

The CIA Saigon Station issued a report 10 January 1968 titled: "The Enemy Threat to Khe Sanh."

The report noted military construction activity northwest of Khe Sanh as "21 foxholes, two fortified hilltops, and heavy trail activity." Enemy patrols were reported on trails from Route 9. Later updates of this report reported regiment sized units from the 325C and 304 Divisions maneuvering into position northwest of Khe Sanh. Anti-aircraft guns 37mm and 57mm were seen on hills to the northwest. Aerial photos revealed new road construction near Ban Dong in Laos along Route 9 and eastward. New storage depots appeared 17 km east of the Laotian border along Route 9.

An NVA "rallier"  (rallier = NVA/VC soldiers taking advantage of the "Chieu Hoi" or "Open Arms"  program,) defected to Captain Kenneth Pipes' Company B Marines on January 20 1968. Lieutenant La Thanh Tonc (Commander, 14th Antiaircraft Company,) provided a wealth of intelligence. He said Khe Sanh was the most important North Vietnamese objective in a larger offensive. They wanted to seize Quang Tri Province, and force the Americans from every base from Laos to Con Thien.

The 325C Division planned to attack Khe Sanh. 5th Battalion 95C Regiment was assigned to take Hill 1015, the highest peak in the area. It overlooked the airfield and its approaches. 6th Battalion planned to attack Hill 861, and 4th Battalion would attack the western end of the airstrip. The 101D Regiment was to attack the east end of the airstrip. The 29th Regiment was in reserve. (It actually moved instead to attack Hue.)

The cooperative Lieutenant was not specific about artillery, but said heavy guns and rockets would support the attacks.

Khe Sanh Map

Khe Sanh Defenses

Khe Sanh was in the far north of South Vietnam, in Quang Tri Province, only 10 km from Laos.

Located in I CTZ, US forces there were under III MAF command. (Marine Amphibious Force III)

Colonel David Lownds commanded the 26th Marine Regiment, that defended Khe Sanh. Defensive forces were about 6000 Marines, under Operation "Scotland."

Defensive positions spanned from west-north-west to north. Company I defended Hill 881, Company K was on Hill 861, and 2nd platoon, Company A sat on the high crest, Hill 950, guarding a radio relay site. The airstrip was defended by 1st Battalion and L Company, and batteries B and C of the 1st Battalion, 13th Marine Artillery.  2nd Battalion defended Hill 558, with E Company at Hill 861A. On 27 January, Captain Hoang Pho and his ARVN 37th Ranger Battalion arrived. They defended the east end of the airstrip. On 22nd January, when the base was under heavy attack, 3rd Marine Division deployed  Lt. Col. John Mitchell's 1st Battalion, 9th Marines to Khe Sanh. They camped 1.5 km west of the main base on a small hill.

Firebase Camp Carroll provided significant artillery support. It was located 25 km northeast of Khe Sanh. The twelve 175-mm guns of 2nd Battalion, 94th Artillery had a 32 km range, and could reach enemy positions surrounding Khe Sanh.

In every position, Khe Sanh defenders "dug in" for the coming battle. Following a visit, General Cushman directed that "all fighting holes have overhead cover capable of withstanding direct hits from 82mm mortars." Ammunition storage was reorganized for better protection.

Air support was significant. Operation "Niagara" and a supply airlift  provided crucial defensive support during the siege. These will be covered later in greater detail.

Dien Bien Phu Comparisons

By late January, US military planners committed to the Khe Sanh defense, despite many references to "possibly another Dien Bien Phu." General Westmoreland wanted to keep, and defend the base. It was a valuable monitoring position for enemy infiltration along the "Ho Chi Minh" trail. Westmoreland envisioned a future invasion of Laos to physically to cut the trails. Khe Sanh would be the support base for this campaign.

Further, Admiral Sharp, Commander-in-Chief, Pacific, pointed out that: "withdrawal from any portion of Vietnam would make immediate and sensational news, not only through the Western news media, but also through the Communist capitals as a major propaganda item."

Another rallier, Vo Manh Hung, claimed that NVA troops would cut Route 9, bring in anti-aircraft guns, and overrun the base, "as Dien Bien Phu was." US intelligence officers placed little faith in his story, but it highlighted the question: Was Khe Sanh merely a diversion, or were the NVA committed to capturing it?

No matter the answer to this question, American intent was clear. President Johnson asked  Westmoreland about the situation. This assessment was circulated for comment, and the Joint Chiefs of Staff unanimously endorsed Westmoreland's conclusion that Khe Sanh could and should be held. President Johnson was convinced, and ordered the military to defend the base "at all costs."

NVA Attacks

Serious action began the evening of 20 January. The NVA had been encroaching a few days earlier.

But, a Marine reconnaissance team was surrounded on Hill 689. They called for artillery support, which enclosed the position in a "protective box." It was effective, and 25 NVA casualties resulted.

However, that was  only a sideshow. Flares appeared over Hill 861, and then 300 NVA troops attacked. Striking from only 100 meters from the crest, NVA blasted holes in the barbed wire with bangladore torpedoes, and assaulted Company K's bunkers and trenches. Company K, commanded by Captain Norman Jasper, fought back aggressively. But, the Vietnamese penetrated 1st Platoon's defenses, and overran the landing zone. Jasper was wounded, and Lt. Saulsbury took over.

Some of 3rd Battalion's 81mm mortars on Hill 881 fired to support Hill 861. The mortars fired 680 rounds that night.

Although the attackers penetrated the perimeter's southwest side, Sergeant Stahl single-handedly counterattacked, distracting the enemy troops, while other Marines recovered casualties. The small group fought hard, and by 0530, the NVA assault was spent. Hill 861 remained in Marine hands.

Immediately after the failed attempt to take Hill 861, NVA artillery  struck the main Khe Sanh combat base. At 0530, artillery, mortar, and rocket fire smothered the airstrip, surrounding bunkers, and trenches. Rounds hit the Marine artillery area, scoring a direct hit on the generator which powered the  digital fire control computer. But, the Marine batteries continued firing, using manual computations.

Within minutes of the opening salvo, the base ammunition depot, "ASP Number 1," was hit. It held more than 1500 tons of ammunition. The explosion threw fragments and unexploded rounds through the air, and landed on fighting positions.

The explosion of ASP 1 immediately created a supply shortage. Incoming rounds smashed into the airstrip, ripping apart steel plates, and damaging helicopters. Combined with ammunition explosions, the shelling destroyed a Bell UH-1 Iroquois helicopter, all weather instruments, most of the airstrip's night lighting, many field telephone lines, bunkers, engineer equipment, generators, the post exchange, and the mess hall.

Nightfall brought no respite for the defenders. At 1950, L Company reported 35 NVA crawling toward its wire near the western end of the airstrip. The Marines opened fire with grenade launchers and light anti-armor weapons (LAAW5). When the action ended an hour later, the North Vietnamese were dragging away casualties, while 14 dead remained on the wire.

During the main base attack,  elements of the 66th Regiment, 304th NVA attacked the village of Khe Sanh. These were defended by the 915th Regional Force Company, including a four-man US Army advisory group. While eventually forced to give up most of the hamlet, defenders established a final perimeter in the headquarters compound. Two relief attempts failed, but the American advisors were evacuated to the main base.

On 22 January, Khe Sanh was the scene of frantic activity. 20 Air Force C-123 sorties delivered another 130 tons of ammunition, as resupply became critical. On 23 January, enemy anti-aircraft fire became a significant threat, with NVA gunners downing a helicopter and a jet fighter in a 20-minute period.

Communist shelling continued, further damaging bunkers, trenches, and the airstrip. The Marines fought back, expending massive quantities of artillery and mortar ammunition in attempts to silence enemy guns. This was very difficult, as NVA gun positions were concealed in dense jungle, visible only when actually firing.

NVA long-range artillery was a real problem for Khe Sanh defenders. The command thought this artillery all fired from Co Roc Mountain. It was southwest of the combat base, across the Laotian border, and outside range of Marine artillery. In addition, aerial bombing was not completely effective, as  these 130-mm guns were in caves, completely camouflaged, and fitted out with rails. The North Vietnamese gunners could roll the guns to the mouth of the cave, fire, and then roll back into the cave for protection. B-52 "Arclight" strikes would quiet these guns for a few hours, but they would resume.

However, there were some positions that the higher command overlooked. Marines on Hill 881 spotted several of these 130-mm guns to the west of their position. Particularly, Corporal

Molimao Nivatoa, a native Samoan blessed with unusually good eyesight, identified these guns using powerful binoculars. Captain Dabney of "I" Company wanted B-52 strikes against these, but his requests were unanswered. However, four guns were hit by Navy and USAF fighter-bombers, guided by a Marine forward air controller, callsign "Southern Oscar," who was flying a O-1E "Birddog."

Aerial Photo Khe Sanh

Tactical Airlift and Operation "Niagara"

From the time the decision was made to hold Khe Sanh, its tenability was almost solely dependent upon airpower. The primary defense of Khe Sanh was sustained tactical strikes and B-52 bombing. Without these, the base would have likely fallen.

The Marine and ARVN force at Khe Sanh depended on airlift for its supplies. With the enemy occupying the high ground around it, and ground supply routes severed, Khe Sanh would have become isolated if not for air resupply. Although III MAF had organic airlift capability, it was beyond their capacity to deliver 235 tons/day required. Thus, the 834th Air Division kept the base resupplied, and evacuated the wounded. The 834th AD delivered over 12400 tons of supplies to Khe Sanh. Of this, 8120 tons were airdropped, and 4310 air landed under very hazardous conditions. C-130 and C-123 transport planes were used for this effort.

Operation Niagara Phase I was an massive intelligence collection effort started in January when NVA activity near Khe Sanh became evident. It included CIA roadwatch teams, recon by secret MACV/SOG teams, and aerial photography.

In addition, hundreds of acoustic and seismic sensors were dropped around the combat base. These had been used in Operation Igloo on the Ho Chi Minh trail. The system quickly proved its worth. The night of February 3-4, sensors detected up to 2000 NVA soldiers northwest of the combat base. Artillery fired on that position. The sensors actually "heard" men screaming, and transmitted sounds of troops fleeing their assembly areas. This force was completely annihilated by artillery. It is perhaps the earliest example of a ground attack entirely thwarted after detection by remote sensor data.

Analysis of incoming rocket, mortar and artillery craters determined the likely source of NVA gun positions. Shell/flash reports, infrared imagery, and analysis of intercepted enemy communications were also used to identify targets. This information was used for air missions as well.

The launch for Operation Niagara II was 21 January. Aircraft in the operating area checked in and out with the ABCCC for target/FAC assignment. A C-130 Hercules aircraft served as the ABCCC. (Airborne Battlefield Command and Control Center) The exception was Marine aircraft under FAC control in the immediate Khe Sanh area.  (FAC = Forward Air Controller)

The ABCCC coordinated air strikes through the Marine sub-DASC at Khe Sanh, or the airborne DASC if on station. (DASC = Marine Direct Air Support Center)

The 20th Tactical Air Support Squadron (20th TASS) was stationed Danang. These were the forward air controllers, FAC, for Niagara, and flew O-1 Birddogs and O-2 Skymasters. These were single engine planes made by Cessna.

The 7th Air Force Commander and his staff directed SLAM-type operations several days prior to the Tet Holidays.  (SLAM = Seek, Locate, Annihilate, and Monitor) The first day's operation used 595 tactical strike sorties (7AF, USMC, and USN,) and 49 B-52 sorties.

From 22 through 29 January, over 3000 tactical strike, and 200 B-52 sorties were flown. Bomb damage assessment (BDA) for these strikes was reported as follows: 346 secondary explosions and fires, sixteen trucks destroyed and seveni damaged, 18 gun positions destroyed and three damaged, 29 bunkers 3 destroyed and ten damaged, 181 structures destroyed and 65 damaged, and 241 killed.

Through 31 March, over 24400 tactical strike and 2500 B-52 sorties were flown. This was the greatest sustained concentration of airpower in Vietnam to date. Assets from Operation Rolling Thunder were diverted to Niagara.

The B-52 bombers were mostly from the 4133rd Bomb Wing at Andersen Air Force base in Guam. Typically, they flew from Guam, dropped bombs at Khe Sanh, and continued to U-Tapao airbase in Thailand. The next day, they refuelled, rearmed, flew to Khe Sanh, dropped bombs, and returned to Guam.

Khe Sanh Picture

Outcome and Analysis

Despite strong NVA attacks, outnumbering the 6000 man defenses, Khe Sanh combat base did not fall. The NVA had an estimated force of 20000 troops in the area. This is better than a 3:1 advantage.

Yet, despite continuous shelling, infantry attacks, and anti-aircraft fire, the Marines held on to the combat base.

The villages of Khe Sanh and Special Forces Camp Lang Vei were lost. Many refugees left the area, and created some problems for military planners.

Operation Pegasus was a relief mission launched on 1 April. The 1st Air Cavalry Division moved in to relieve the 26th Marine Regiment at Khe Sanh. They reopened Route 9 between Ca Lu and Khe Sanh. However, in June 1968, MACV decided to abandon Khe Sanh. It was evacuated and dismantled under Operation Charlie.

The NVA/VC confirmed casualties during the main battle through 31 March were 1602 dead, 7 prisoners, and 2 ralliers. However, American intelligence estimates placed this death toll between 10000 to 15000. It is believed that tactical airstrikes and B-52 bombing caused the majority of these. The NVA attack force was severely damaged, and could not continue offensive operations in the coming months.

American and ARVN casualties were 205 killed at Khe Sanh, with 1668 wounded. About half the wounded required evacuation.

The amount of ordinance used was incredible. American aircraft  dropped 103500 tons of bombs, and  artillerymen fired 102660 rounds of various calibers. The NVA fired 10908 rounds of artillery, rockets, and mortars. The difference in artillery firepower alone is striking.

Dien Bien Phu comparisons include intelligence, airpower, and resupply by air. The Americans had very good intelligence prior to the siege. The French intel at Dien Bien Phu was limited.

American airpower was vastly greater than French efforts at Dien Bien Phu. And, despite heavy anti-aircraft gun interference, American resupply was more than sufficient. The French resupply was very poor, and ultimately the DBP defenses lacked ammunition at critical times.

Returning to the question of whether Khe Sanh was a diversion,  some insight was gained through interrogation of Nam Dong. He was a high-ranking Viet Cong cadre, arrested while on his way to a meeting of the Central Office of South Vietnam. (COSVN) Nam Dong told interrogators: (paraphrased)  "The strategy was  different from plans during the war with the French, due to these considerations: (1) France's military might was relatively weak, while America's present strength is incomparable; (2) In the War against the French, the victory of Dien Bien Phu was directly instrumental in bringing about the Geneva agreements. No such victories could be expected against the Americans."

It seems that the NVA did not really expect to capture Khe Sanh. They probably attacked it to check any American drives into Laos, as General Giap suggested. The attacks tied up much US airpower. But, airpower could not be used to any large degree in cities like Hue or Saigon, anyway.

References

"US Marines in Vietnam The Defining Year 1968," Jack Shulimson, Charles R . Smith, and David A . Dawson

"Khe Sanh Operation Niagara," CHECO Warren A. Trest

"Operation Niagara: Siege of Khe Sanh," Peter Brush, Vietnam Magazine

"A Description and Analysis of the Sieges of Khe Sanh and Dien Bien Phu," Roger L. Purcell

"The Viet Cong TET Offensive 1968," Pham Van Son, Le Van Duong, and Nguyen Ngoc Hanh

Campaign Series Vietnam | Comrade Giap's Clever Nuggets

General Vo Nguyen Giap

 

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