H017.1 U.S. Navy Operations in Vietnam, Jan-Mar 1968
S.J. Cox, 25 Mar 2018
Siege of Khe Sanh

On 21 Jan 1968, a force of well over 20 thousand North Vietnamese Army (NVA) troops laid siege to the U.S. Marine combat base near the isolated village of Khe Sanh, located about 7 miles from the Laotian border and about 15 miles south of the “Demilitarized Zone” on the border between North and South Vietnam in the far northwest corner of South Vietnam. From then until the siege was finally lifted in April by a U.S. Army over-land operation, the 6,000 Marine defenders endured near constant rocket and artillery attacks, sometimes over 1,000 rounds per day (with a peak of 1,307 one day on 23 Feb.)

Although the NVA force never launched an all-out assault, smaller-scale ground attacks and infiltration attempts were frequent. The only way to resupply the Marines was by air-drop, or high-risk landings by C-130’s and helicopters at the airfield.

The situation at Khe Sanh had a superficial similarity to Dien Bien Phu in North Vietnam (then part of French Indochina) in 1954 when a major French force was surrounded and forced to surrender to the Viet Minh, which subsequently resulted in Vietnam gaining its independence from France (and subsequently being split in two, North and South.) The press and even high-ranking U.S. military played up the resemblance, and as a result Khe Sanh became a “must win” for the U.S. The NVA, on the other hand, could have easily bypassed it if they chose, which was pointed out by senior U.S. Marine commanders in Vietnam, who questioned the wisdom of occupying and holding Khe Sanh.

However, General Westmoreland believed that drawing the NVA into a set-piece battle in an isolated area, where the risk of civilian and collateral damage was minimal, would enable the full application of U.S. power to pin down and destroy what had been to that point a mostly elusive enemy (i.e, a “Dien Bien Phu in reverse.”) In addition, President Johnson himself had ordered that Khe Sanh must not be allowed to fall. So, the Marines were stuck, defending an otherwise insignificant piece of ground against an enemy whose rockets outranged the Marines’ artillery. The result was the one of the largest and most intense air-to-ground bombardments in history. Over the next several months, U.S. Air Force, Marine, and Navy aircraft would drop more bombs around Khe Sanh in “Operation Niagara” than had been dropped in the entire Korean War or against Japan in 1945.

At the time of the NVA attack on Khe Sanh, U.S. Navy aircraft launching from aircraft carriers on “Yankee Station” in the Gulf of Tonkin were flying daily strikes (weather permitting) on targets in North Vietnam as part of Operation Rolling Thunder, ongoing since 1965. The Navy suffered increasing losses throughout 1967 as North Vietnam’s new surface-to-air missile (SAM) and radar network, and increasingly dense anti-aircraft artillery (AAA) coverage, became more effective – thanks to Soviet and Chinese equipment brought into North Vietnamese ports, where the U.S. rules of engagement prohibited U.S. strikes. (see H017.3 for more on the Navy’s participation in Rolling Thunder, although I would add that about 61 U.S. Navy Air Wing Commanders and Squadron Commanders and Executive Officers were lost during the course of the Vietnam War, a significant loss to Naval Aviation leadership at the time.)

Normally, three carriers were assigned to Rolling Thunder; two on Yankee Station, each covering a 12 hour period of flight operations, and a third undergoing replenishment and some R&R, usually at Subic Bay in the Philippines. (Earlier in the war a carrier would also operate at “Dixie Station” off South Vietnam to provide close air support to U.S. Army and Marine forces in the South, while the Air Force built up its base structure in Thailand and in South Vietnam (which were subject to Viet Cong mortar and rocket attacks) before that station was discontinued in 1966.) During the siege of Khe Sanh, and the Tet Offensive, sometimes four and even five carriers operated from Yankee Station, including USS TICONDEROGA, USS RANGER, USS KITTY HAWK, USS CORAL SEA, and later USS ENTERPRISE (after concluding response to the seizure of the intelligence collection ship USS PUEBLO by North Korea. TICONDEROGA and RANGER were also drawn off Yankee Station briefly in reaction to the PUEBLO capture.) The carrier force operating in support of Rolling Thunder was designated Task Force 77, and was under the operational control of the U.S. SEVENTH Fleet.

During the northeast monsoon season, which resulted in heavy cloud cover North Vietnam, Navy aircraft from Yankee Station would fly close support missions over South Vietnam, which was generally clear (the situation reversed during the southeast monsoon.)

In January 1968, monsoon conditions prevailed over North Vietnam, so the Navy all-weather A-6 Intruders flew the great majority of strikes into North Vietnam. The other Navy carrier aircraft contributed to the defense of Khe Sanh with over 5,300 sorties delivering almost 8,000 tons of bombs (by comparison, the Air Force flew almost 9,700 sorties (but few into North Vietnam at that time) and Marine air flew over 7,000 sorties in support of Marines on the ground.) On a typical day, there would be 350 tactical aviation (TACAIR) strike sorties from all services and 60 B-52 bomber strikes by the Air Force, sometimes within 100 yards of the Khe Sanh perimeter.

The result was very high NVA casualties in the thousands, and a major reason why the NVA didn’t mount a major ground assault on Khe Sanh, although they did deploy armor for the first time in the South in one assault on South Vietnamese forces in a nearby village.

The air operations in the vicinity of Khe Sanh also renewed and exacerbated an inter-service fight over whether air operations should be commanded by a single commander (as the Air Force wanted) or remain under the command of their own service (as the Marines and Navy wanted, and most of the Army.) In this case, General Westmoreland agreed with the Air Force, despite vociferous objections by the Marines in particular, although this food fight continued all the way to Desert Storm and beyond.)

A significant U.S. Navy contribution to the defense of Khe Sanh were acoustic/seismic sensors dropped by specially-modified OP-2E Neptune aircraft of the Special Naval Observation Squadron, VO-67. Marine defenders at Khe Sanh credited the sensors dropped by the Neptunes for providing 40% of the actionable intelligence enabling artillery fire and air strikes against NVA movements around Khe Sanh. For many years, VO-67’s operations were kept secret, and so are not mentioned in many accounts. VO-67 was a clandestine Navy squadron based in Thailand, flying P-2 Neptune ASW aircraft that had been modified to conduct armed ground-attack reconnaissance and delivery of Seismic Intrusion Detectors (ADSID) and Acoustic Seismic Intrusion Detectors (ACOUSID,) which could detect troop and vehicle (and elephant) movement on the ground, and were based on ASW sonobuoy technology. The program was “Muscle Shoals” which later became Operation Igloo White.

In January 1968, VO-67 was engaged in development and testing of the sensors, deploying them on the Ho Chi Minh Trail in Laos, which provided early warning of increased NVA reinforcement and supply activity before the attack on Khe Sanh and the Tet Offensive. Once the attack on Khe Sanh commenced, the VO-67 aircraft were immediately pressed into full operational service, delivering 316 sensors around Khe Sanh in the first month commencing on 22 Jan. Accurate sensor placement required a low altitude delivery, making the planes easy targets. Over the course of the next year, three OP-2E aircraft would be shot down with the loss of 20 aircrewmen. One of the lost aircraft was piloted by CDR Paul Milius, who remained at the controls of the aircraft until his crew successfully bailed out (one was mortally wounded when the plane was hit, but the seven who bailed out were rescued.) Milius then bailed out but was never seen again (and his body has never been recovered.) Milius was promoted to captain while missing in action, and awarded the Navy Cross. The Burke-class destroyer USS Milius (DDG-69) is named in his honor. The secret squadron would be awarded a Presidential Unit Citation, in 2008.

Another significant Navy contribution to the defense of Khe Sanh was the role of Task Force Clearwater on the Cua Viet and Perfume Rivers in northern South Vietnam. Although all the supplies to the Marines at Khe Sanh were airlifted (or dropped) in, the vast majority of those supplies were first shipped up the Cua Viet River by landing craft and other small vessels to a staging area, where they were loaded aboard aircraft. Armored monitors and other vessels of TF Clearwater successfully defended the transport of supplies on the river from Viet Cong ambushes. During the Tet Offensive, fighting along the river was at times intense.

The commander of U.S. Naval Forces in Vietnam, RADM Kenneth Veth, initially resisted allocating forces for TF Clearwater, because they would come at the expense of forces operating in the critical Mekong Delta, but he was convinced by intelligence reports (many provided by U.S. Navy reconnaissance aircraft flying in southern North Vietnam) of the NVA build-up, and detached some of his forces from the Delta, including a Seabee Battalion. The establishment and arrival of Task Force Clearwater proved to be “just in time.”

In the end, the Marines at Khe Sanh held, at a cost of 274 dead (the U.S. Army also suffered numerous casualties in the relief force that broke the siege (Operation Pegasus.)) General Westmoreland, Commander of all U.S. forces in Vietnam, was so fixated on the defense of Khe Sanh that he initially believed the subsequent Tet Offensive was actually a diversion for a major attack on Khe Sanh. The reality was almost certainly the exact opposite.

With the arrival of U.S. Army reinforcements in April, the NVA temporarily withdrew, and the U.S. claimed victory. In June, the U.S. withdrew from Khe Sanh, destroying all the facilities, and the North Vietnamese then claimed victory. The USS PELELIU (LHA-5,) commissioned in 1980 and decommissioned in 2015, was originally to be named USS KHE SANH (and then USS DA NANG,) before the name PELELIU (a WWII battle) was agreed upon.
The Tet Offensive

The Tet Offensive, which commenced on 30 Jan 1968 with near simultaneous attacks on over 150 South Vietnamese targets, was arguably the turning point of the Vietnam War. It was a devastating military defeat for the NVA and especially the Viet Cong. Casualty estimates are pretty unreliable but may have been as high as 45-58,000 killed including the “mini-Tets” that occurred over the next eight months.

Much to the surprise of the North Vietnamese (who thought they had been soundly defeated,) and to the consternation of U.S. military commanders (who thought they had won a decisive victory,) the Tet Offensive turned out to be a massive psychological, propaganda and strategic win for North Vietnam (not so much for the Viet Cong, who never really recovered.) Although the South Vietnamese Army (ARVN) had acquitted itself pretty well (No ARVN units broke and few soldiers defected) the outcome resulted in widespread demoralization (particularly in the South Vietnamese cities, which to that point had largely been spared from the fighting) and loss of faith in the ability of the South Vietnamese government (which was widely viewed as heavily corrupt) to protect the citizenry.

What truly faltered was the will of the United States to continue to sustain the high casualties to continue a war that now appeared to have no end in sight.

Contrary to many accounts, the target of the Tet Offensive was not the political will of the United States; that outcome turned out to be an unanticipated bonus to the North Vietnamese. The real objective of the “General Offensive and Uprising of Tet Mau Than 1968” was to take the fight to South Vietnamese cities and provoke a general uprising by the people of South Vietnam against the South Vietnamese government. In this regard, the Tet Offensive failed, at least in the short run, although the damage it did to the South Vietnamese government would prove fatal in the long run.

Another misconception about the Tet Offensive regards intelligence and warning. Actually there was considerable warning at the end of 1967 and beginning of 1968 that a major North Vietnamese and Viet Cong Offensive in the South was coming soon, a fair amount of it provided by U.S. Navy reconnaissance flights over southern North Vietnam that reported the increased southward flow of NVA personnel and supplies.

However, as one South Vietnamese commander put it, even if the U.S. had access to the full North Vietnamese plan, they (the U.S.) wouldn’t have believed it. The U.S. had even captured a Viet Cong Op Order that basically laid out the entire plan. The reason the U.S. didn’t believe it was because the U.S. analysis of the warning indicators was focused on enemy probable courses of action based on capability rather than enemy intentions.

U.S. Commanders, and intelligence analysts, did not believe that the NVA and Viet Cong had the forces necessary to successfully execute such a massive, simultaneous offensive. Nor did much of the leadership of North Vietnam believe it for that matter, which was deeply divided on the wisdom of conducting such an offensive. The Tet offensive was only approved after a purge of pro-negotiation/protracted guerilla war/political solution faction officials in the summer of 1967 (the “Revisionist Anti-Party Affair”) which left the hard-core militant anti-negotiation faction officials in the dominant position.

The situation in North Vietnam was actually very dire with a collapsing economy due to the U.S. bombing, with a need to do something different (negotiate or attack) to get themselves out of the jam. U.S. Commanders had lots of data and metrics about increasing NVA and Viet Cong activity; what they lacked was what ADM Nimitz had at Midway; accurate intelligence about enemy intent (and which ADM Nimitz believed.)

It turned out the North Vietnamese doubters, U.S. Commanders and intelligence analysts were correct. The Vietnamese Communists lacked the forces to successfully execute such a massive offensive and they were soundly thrashed with very high casualties within a few days (except in Hue City.) Militarily, the Tet Offensive was a disaster for the North Vietnamese, and was initially viewed as a failure by them.

Over the months preceding the Tet Offensive the North Vietnamese engaged in extensive operational deception designed to focus U.S. military attention to the border areas and away from the coastal cities. NVA operations at Con Tien, just south of the DMZ, and Dak To in the Central Highlands, made little military sense and cost the NVA heavily, but succeeded in the deception objective. While U.S. Commanders viewed the operation at Kha Sanh as an attempt by North Vietnam to replicate their great victory against the French at Dien Bien Phu, the real objective was just to tie down a large number of U.S. forces, and divert U.S. attention from the preparations for the country-wide Tet Offensive. In this objective, the North Vietnamese mostly succeeded.

The North Vietnamese government also announced that they would honor a truce between 27 Jan and 3 Feb in conjunction with Tet, the Vietnamese New Year holiday, which they actually had no intention of doing. The South Vietnamese took the bait, and in some locations over half the ARVN troops were away from their post on holiday leave when the offensive commenced. Although several premature Viet Cong attacks the day before the offensive commenced resulted in a recall initiation, it was too late to get many ARVN troops back to their bases.

President Johnson had also previously announced a unilateral Christmas truce and bombing pause, which the North Vietnamese used, as they usually did, to great effect for massive unmolested movement of troops and material and generally improving their defensive (and in this case, offensive) posture. Of note, however, one of General Westmoreland’s key commanders, General Frederick Weyand (who had served as an intelligence officer earlier in his career) had become suspicious of North Vietnamese intentions and convinced General Westmoreland on 10 January to pull back about several brigades of U.S. troops from the Cambodian border to Saigon, an action that proved critical in quickly defeating the attacks directed against the South Vietnamese capital city.

The Tet Offensive commenced on the night of 30-31 Jan 1968 with attacks by about 84,000 NVA and VC troops against about 155 South Vietnamese cities, government and military targets, including some U.S. targets such as the U.S. embassy in Saigon. Communist forces attacked 36 of the 44 provincial capitals in South Vietnam, and almost every military installation came under some form of mortar, rocket attack or infantry assault.

Despite the surprise, the attack on the U.S. embassy was quickly beaten back, as was a badly coordinated attack on the South Vietnamese Navy Headquarters in Saigon, partially thanks to a U.S. Navy Advisor who alertly called in support from U.S. Military Police as firing began at the compound gate.

In almost all cases, the enemy attacks were beaten back in a matter of a day or two, with the exception of the old Vietnamese Imperial capital of Hue, were two NVA battalions succeeded in occupying the old citadel, which would take ARVN and U.S. Marine forces until 25 February to re-capture, at a cost that included 216 Marines killed and 1,600 wounded. Other NVA forces also force-marched from the Khe Sanh area to the Hue area to help slow down the ARVN and U.S. Marine counter-attack.

The AEGIS class cruiser USS HUE CITY (CG-66) would be named in honor of the U.S. Marines who fought and died in one of the longest and bloodiest battles of the entire war, and is the only U.S. Navy ship named after a Vietnam War battle. Besides casualties inflicted on ARVN forces and South Vietnamese civilians caught in the cross-fire, the North Vietnamese deliberately executed at least 2,800 South Vietnamese civilians (some estimates are even higher) in Hue; basically anyone who had some connection with the South Vietnamese government, as well as teachers, religious leaders, and a small number of European and American civilians.

A combination of poor weather, which impeded air support, and a desire to minimize the destruction of a historic and culturally significant site, contributed to the length of time it took to recapture the city (The old city/citadel of Hue is now a UNESCO World Heritage Site.)

As part of the Tet Offensive, Viet Cong forces attacked 13 of the 15 largest cities in the Mekong River Delta, the strategically vital “breadbasket” of South Vietnam. With almost no roads, only the labyrinth of rivers and canals provided the means for transportation. General Westmoreland would later credit U.S. Navy forces, particularly the joint Army-Navy Mobile Riverine force (TF 117) with “saving” the Delta.

This may have been somewhat of an exaggeration, but there is no question that the Navy’s riverine forces played a critical role in the rapid movement of U.S. Army troops to quickly eject Viet Cong forces from every city they attempted to occupy. In several cases, U.S. Navy SEALS, from five SEAL detachments transported by Navy riverine craft, drove off Viet Cong forces.

At the time of the Tet Offensive, U.S. Naval forces in Vietnam were under the overall command of RADM Kenneth Veth. Operating within the Mekong River Delta were two major task forces. Task Force 116, the River Patrol Force, consisted of 13 sections of 10 PBR boats each (PBR’s were small four-man patrol boats generally armed with .50 cal and M60 7.62mm machine guns and a 40mm grenade launcher.) TF116 was responsible for executing Operation Game Warden, the interdiction of Viet Cong movement and supply activity on the waterways of the Mekong Delta.

The second task force, TF117 was the Mobile Riverine Force (MRF,) under the command of Commodore Robert Salazar, which consisted of over 100 armored watercraft of various types and sizes, manned by the U.S. Navy, but responsible for the rapid transport (and defense) of a brigade-sized U.S. Army force. The Navy riverine force was also supported by a Navy squadron of light attack helicopters, the “Seawolves” of HA(L)-3 flying modified HUEY helicopter gunships.

During the course of the war, the Navy Riverine Forces executing Operation Game Warden would lose about 200 men, but achieve a 40-to-1 kill ratio, amongst the best of any force in the war (for a metric that as it turned out didn’t mean much.) The Seawolves would fly 120,000 combat sorties during the war at a cost of 44 personnel killed. The U.S. Navy forces in the Delta also provided significant training to the South Vietnamese Navy, which eventually operated about 650 vessels of various types of their own. In the end, when South Vietnam fell in 1975, it was the U.S.-trained South Vietnamese Navy forces in the Delta that held out the longest.

As part of the Tet Offensive, the North Vietnamese attempted to surge supplies into South Vietnam via the sea using trawlers and other smaller inconspicuous-looking vessels. U.S. Navy ships operating as part of Operation Sea Dragon (the bombardment of the North Vietnam coast) interdicted some of this traffic. Most of the seaborne traffic was interdicted by TF 115, the Coastal Surveillance Force, executing Operation Market Time. Market Time was a mostly U.S. Navy operation with significant U.S. Coast Guard participation using patrol aircraft and about 145 smaller vessels, such as PCF “Swift” boats, to track supply vessels as they went far into the South China Sea before making a run for the South Vietnamese coast to drop off supplies for the Viet Cong.

As much as 90% of Communist seaborne resupply and infiltration was estimated to have been interdicted as a result of Market Time. U.S. Navy destroyers also conducted naval gunfire support (NGFS) to U.S. Marine and Army operations along the coastline during the Tet Offensive (and the re-activated battleship USS NEW JERSEY, would arrive later in 1968.) It should also be noted that U.S. allies, especially Australia, participated in many of the naval operations off the Vietnamese coast.

In the end, most of the NVA and Viet Cong forces that initiated the Tet Offensive were quickly driven off by ARVN and U.S. counterattacks, with the exception of Hue City, which dragged on for several weeks, and the siege of Khe Sanh, which dragged on for several months.

What the American public saw, however, was not a great victory, but a steady stream of bloody young draftee American soldiers and Marines beamed directly into the comfort of their living rooms on their new color TV’s. There are those who have argued that “the media” lost the war by prematurely declaring the Tet Offensive to be a Communist victory.

However a case can also be made that it was the loss of credibility by the U.S. government and senior military leadership that was the real root cause. For over a year, senior U.S. leaders had been telling the press that things were going great, and according to plan, when in reality they knew it wasn’t. The Tet Offensive burst that bubble, resulting in what the media termed the “Credibility Gap.” Once the U.S. military leadership had compromised its integrity, the media coverage turned increasingly skeptical and even hostile. (This is actually a difficult dilemma, because being publically truthful about things going badly arguably gives aid and comfort to the enemy and adversely affects morale amongst the troops and on the home front. The solution in previous wars had been censorship, which in the modern age is no longer effective.)

In a special CBS TV news broadcast on 27 Feb 1968, network anchor Walter Cronkite (deemed “the most trusted man in America”) stated that victory in the war was no longer in sight, and what America was in for was a protracted stalemate, and implied that the metrics for success provided by the U.S. government could be no longer trusted.

The week before Cronkite’s broadcast, the U.S. had suffered 543 killed and 2,547 wounded (the peak for the war,) and over the course of the Tet Offensive 1,526 killed and about 7,700 wounded. It was a price that the American public was increasingly unwilling to pay. President Johnson supposedly said that if he’d lost Cronkite, he’d lost Middle America. There is reason to believe LBJ didn’t actually say that, but it was essentially true.