NAVA L H I STORY & H ER ITAGE COM M A N D | THE U.S. NAVY AND THE VIETNAM WAR

Knowing the Enemy

Naval Intelligence in Southeast Asia

Richard A. Mobley and Edward J. Marolda
Front Cover: Detail from Sudden Squall by R. G. Smith. 
THE U.S. NAVY AND THE VIETNAM WAR 

Edward J. Marolda and Sandra J. Doyle, Series Editors

Knowing the Enemy

Naval Intelligence in Southeast Asia

Richard A. Mobley and Edward J. Marolda

DEPARTMENT OF THE NAVY

WASHINGTON, DC

2015
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Library of Congress Cataloging-in-Publication Data

Names: Mobley, Richard A., 1952- author. | Marolda, Edward J., author.

Title: Knowing the enemy : naval intelligence in Southeast Asia / Richard A. Mobley and Edward J. Marolda.

Description: U.S. government official edition. | Washington, DC : Department of the Navy, 2015. | Series: The U.S. Navy and

the Vietnam War | “Published by Naval History & Heritage Command in partnership with the Naval Historical

Foundation”--Title page verso. | Includes bibliographical references.

Identifiers: LCCN 2015044625| ISBN 9780945274780 (pbk. : alk. paper) | ISBN 9780945274797 (pdf)

Subjects: LCSH: Vietnam War, 1961-1975--Military intelligence--United States. | Vietnam War, 1961-1975--Naval operations,

American. | United States. Navy--History--Vietnam War, 1961-1975.

Classification: LCC DS559.8.M44 M63 2015 | DDC 959.704/38--dc23 LC record available at http://lccn.loc.gov/2015044625

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CONTENTS

Introduction 1

Interpretation of the Threat to Southeast Asia 5

The Question of Seaborne Infiltration 9

Intelligence Gathering in Laos 13

Collecting Intelligence on the Enemy’s Doorstep 17

Intelligence Support during the Tonkin Gulf Incidents 21

Preparations for War in Southeast Asia 25

Navy Tactical Reconnaissance 29

A Helping Hand to Hanoi: Sino-Soviet Bloc 

Military Assistance 41

The Defense of North Vietnam 45

The Post-1968 Air War in North Vietnam and Laos 51

Intelligence and the War on the Coast 55

Cambodia’s Open Door: Sihanoukville 65

The Naval War in South Vietnam 73

Naval Intelligence and the Fight for South Vietnam 77

NILOs in Action 83

Intelligence in the Linebacker Campaign 91

Conclusion 95

Sidebars

A Recce Pilot in Harm’s Way 14

In a MiG’s Sights 30

The Short, Dangerous Life of the Ghost Squadron 32

CT Duty at “Rocket City” 37

Sculpin and the Sinking of an Infiltrating Trawler 69

Zumwalt’s Eyes and Ears 85

Jack Graf: A Naval Intelligence Hero 87

The Authors 98

Acknowledgments 99

Suggested Reading 100
vi

President Lyndon B. Johnson, flanked by Secretary of Defense Robert S. McNamara (bottom right) and Chief of Naval 

Operations Admiral Thomas H. Moorer, during a visit to aircraft carrier Enterprise (CVAN-65). 

NHHC Vietnam Collection
1

INTRODUCTION

I

ntelligence figured prominently in the causes, 

evolution, and results of the Vietnam War. 

At the national level the National Security 

Council (NSC), the Central Intelligence 

Agency (CIA), the National Security Agency (NSA), 

the Defense Intelligence Agency (DIA), the State 

and Defense departments, government-contracted 

“think tanks,” and a host of other organizations 

gathered and analyzed intelligence. The Office of 

Naval Intelligence (ONI), while directly serving 

the Navy, also provided the national security 

establishment with comprehensive analyses of 

broad international developments. The dedicated 

professionals in these agencies labored to identify 

the nature of the threat faced by the United States 

in Southeast Asia. They debated whether North 

Vietnamese leaders took their orders from Moscow 

and Beijing or charted an independent course, and 

they argued over the extent of external support 

for the insurgency in South Vietnam. There were 

heated disagreements over how much control 

Hanoi exercised over the National Liberation Front 

(NLF) in South Vietnam (the Viet Cong [VC]). 

NSA, for instance, weighed in on this issue in 1961 

when it discovered through communications intercepts that North Vietnam employed a clandestine 

radio network that linked Hanoi with 114 Viet 

Cong receiving stations in South Vietnam. Other 

agencies also drew conclusions about the enemy’s 

capabilities and intentions. Analysts attempted to 

discern which of the leaders in Hanoi had the most 

clout in guiding the strategy to be employed against 

the South Vietnamese and their American allies. A 

major question was the likelihood of the People’s 

Republic of China (PRC) or the Soviet Union 

(USSR) intervening directly in the conflict.

The United States and its allies lost the Vietnam 

War in large part because American leaders 

failed to understand their primary opponent—the 

Democratic Republic of Vietnam (DRV). Presidents 

John F. Kennedy and Lyndon B. Johnson and their 

principal political and military advisors developed a 

strategy based on the assumptions that U.S. military 

power would in fairly short order compel North 

Vietnam to cease its support of the Communist 

insurgency in South Vietnam; that Hanoi would 

relent under a cascade of U.S. Navy and Air Force 

bombs; and that U.S. forces in South Vietnam would 

prevent a Communist victory there. In contrast, 

America’s enemies demonstrated that they intended 

to fight—despite the heavy cost in resources and 

their citizens’ lives—until they had united all of 

Vietnam under the Communist flag. 

As Washington’s initial strategic assumptions 

proved false, and despite the national intelligence 

community’s accurate appraisal of the enemy’s 

determination to fight on to victory, Johnson and his 

successor, Richard M. Nixon, redoubled the military 

effort in hopes of compelling Hanoi to negotiate an 

end to the war—at an advantage to the United States. 

This goal also proved illusory because the enemy 

held the strategic initiative throughout the war and 

more often than not beat the forces of America’s 

Vietnamese, Laotian, and Cambodian allies on 

the battlefield. Nonetheless, devastating U.S. air 

strikes, the mining of Haiphong in 1972, and North 

Vietnam’s growing isolation from the international 

Communist movement persuaded Hanoi to sign the 

Paris Agreement on Ending the War and Restoring 

Peace in Vietnam on 27 January 1973. 

 The U.S. Navy’s intelligence establishment, 

while sharing in the overall national-level interpretive successes and failures, routinely provided good 

intelligence support to naval operating forces and 

saved American lives throughout the Vietnam War. 

Naval intelligence enabled the aircraft of Task Force 
2

77 to operate effectively in the hotly contested skies 

of North Vietnam and over the heavily defended Ho 

Chi Minh Trail in Laos. Timely intelligence helped 

the ocean patrol forces of Operation Market Time 

negate the enemy’s seaborne infiltration of war 

materials into South Vietnam. Intelligence support 

significantly aided the Navy’s riverine units in their 

operations to deny the enemy control of the Mekong 

Delta. Finally, naval intelligence organizations in the 

United States, in the Western Pacific, and in South 

Vietnam provided vital information on the movement of Communist forces afloat and ashore and the 

importation of war materials into North Vietnam 

and Cambodia from the Soviet Union, the People’s 

Republic of China, and other nations. 

Through much of the Vietnam War, the 

national intelligence community had an uneven 

understanding of the other side. The Washingtonbased agencies developed a good appraisal of 

the North Vietnamese order of battle, support 

from the other Communist nations, and various 

enemy operational and tactical methods. On the 

other hand as Richard Helms, former head of the 

CIA, has observed, Washington failed to acquire 

solid intelligence on the enemy’s decision-making 

process at the Hanoi level. No U.S. agents penetrated the leadership circle around Ho Chi Minh. 

The intelligence organizations, including those 

in theater, provided inconclusive evidence of the 

success or failure of U.S. attempts to interdict the 

Ho Chi Minh Trail and the enemy’s capabilities and 

intentions prior to the Tet Offensive of 1968. 

Since the war, scholars have been hampered by 

their inability to access sensitive documents held in 

the government offices, archives, research institutions, and libraries of the DRV, USSR, and PRC. 

So-called “Kremlinologists” and other Western 

analysts earned fame developing theories based 

on a small amount of credible information from 

various sources. Since the end of the Cold War, 

however, the release, and in some cases translation 

into English, of high-level strategy and policy 

documents housed in repositories in Hanoi, Beijing, 

and Moscow have sparked a robust investigation of 

the events of the war. Numerous Russian, Chinese, 

and Vietnamese veterans have published memoirs, 

spoken publicly, and sat for interviews on their 

experiences in the conflict. 

These materials, including the Socialist Republic 

of Vietnam’s official history of the war, make it 

clear that Hanoi could not have prevailed against 

the United States had Moscow and Beijing not 

provided massive amounts of military assistance. 

These Communist countries helped North Vietnam 

build one of the world’s most formidable air defense 

systems and armed Communist military forces with 

advanced aircraft, tanks, and artillery. China also 

helped North Vietnam rebuild the heavily bombed 

railroad and road systems, bridges, and industrial 

facilities. Of equal importance Mao Zedong’s nation 

eventually deployed over 320,000 troops to North 

Vietnam, freeing the latter country to send most of 

its soldiers to fight in the South. The records released 

after the Cold War also detail the enemy’s intelligence and counterintelligence programs, some of 

which proved especially effective in anticipating and 

thwarting U.S. operations. 

The high security classification of U.S. 

information relating to the Vietnam War has 

until recently limited our understanding of how 

the naval intelligence community accomplished 

its secretive mission. Not only were day-to-day 

operations classified, but in most cases secrecy 

hampered a detailed public discussion of most of 

the organization’s missions that contributed to 

the wartime intelligence effort. Consequently, the 

larger Navy and national populations often had 

little understanding of either the magnitude or 

impact of the Navy’s multiple intelligence efforts. 

Following U.S. government declassification efforts 

spanning decades, we can at last acknowledge the 

efforts that demanded intellectual acumen, dedication to the profession, and on occasion the sacrifice 

of lives. The thousands of declassified documents 

now available afford us ample evidence to gauge 

the scope of naval intelligence efforts even though 
3

some of the information on sources and methods of 

intelligence remain classified.

To capture the broad scope of multiple naval 

intelligence efforts, this study discusses the work 

of commands focused primarily on the collection 

or analysis of intelligence, whether or not they had 

the word “intelligence” in their names. The Naval 

Security Group (NSG), Naval Investigative Service 

(NIS), and Direct Support Units (DSU), for example, 

made huge intelligence contributions to the war 

effort. These and other organizations gathered different types of intelligence, for instance signals intelligence that included communications intelligence 

(COMINT) and electronic intelligence (ELINT), 

human intelligence (HUMINT), and imagery intelligence from satellites and aircraft. 

Officer and enlisted personnel engaged in 

intelligence collection often did their dangerous 

but vital work in direct contact with the enemy. 

The naval aircrews of reconnaissance aircraft flying 

their missions over Southeast Asia suffered high 

casualty rates. For example, the highly secretive 

Aerial Observation Squadron (VO) 67 lost 20 air 

crewmen killed during only two months of sensor 

emplacement missions over North Vietnam and 

Laos. Combat took the lives of SEAL commandos 

and Naval Intelligence Liaison Officers (NILOs), 

whose primary duties entailed gathering intelligence 

on North Vietnamese and Viet Cong combat units 

and strongholds and the movement of supplies in the 

Mekong Delta. 

Not only naval but national intelligence organizations served the Navy’s need for accurate, timely 

information on the enemy. The National Security 

Agency and associated field sites in the combat 

theater, including those of the Naval Security 

Group, directly supported warships and aircraft 

squadrons operating off North Vietnam’s shores 

and in the skies over Haiphong and Hanoi. CIA U-2 

and A-12 aircraft provided film of enemy military 

concentrations in North Vietnam and southern 

China. The National Photographic Interpretation 

Center (NPIC), a forerunner to today’s National 

Geospatial-Intelligence Agency, provided the fleet 

with comprehensive imagery readouts of North 

Vietnam’s naval and other military capabilities. •
4

Southeast Asia. 

NHHC Vietnam Collection
5

INTERPRETATION OF THE THREAT TO SOUTHEAST ASIA

I

n 1959 the U.S. national security establishment concluded that the People’s Republic 

of China and the Democratic Republic of 

Vietnam had finally decided to achieve their 

foreign policy goals through violence and armed 

struggle. Mao Zedong publicly pledged China’s 

support to Communist insurgent movements 

in Indonesia, Malaya, and Indochina, including 

Laos and South Vietnam. The Office of Naval 

Intelligence feared that “further development of 

the Chinese Communist hard line could lead to 

new emphasis on the development of indigenous 

Communist guerrilla capabilities in various parts 

of Southeast Asia, and possibly even to limited war 

adventures” by Beijing. That May, Ho Chi Minh, 

Le Duan, and the other leaders of North Vietnam 

opted for armed struggle to destroy the nonCommunist government of South Vietnam headed 

by President Ngo Dinh Diem. North Vietnam began 

construction of what later became known as the 

Ho Chi Minh Trail from North Vietnam, through 

southern Laos, and into Cambodia and South 

Vietnam. Communist training “cadres”—fighters 

steeped in guerrilla warfare—and military supplies 

began flowing down the trail. In 1960 Communists 

in South Vietnam, under Hanoi’s guidance, created 

the National Liberation Front to fight the government of the Republic of Vietnam. 

Admiral Harry D. Felt, Commander in Chief, Pacific, meets with Secretary of Defense Robert S. McNamara and Chairman 

of the Joint Chiefs of Staff General Lyman L. Lemnitzer in early 1962 to discuss the crisis situation in Indochina. 

NHHC Vietnam Collection
6

To secure the Ho Chi Minh Trail, in 1959 North 

Vietnam and China began providing significant 

military assistance and advice to an indigenous 

Laotian Communist movement, the Pathet Lao. 

From 1959 to 1962 Pathet Lao guerrillas supported 

by North Vietnamese regular units battled the forces 

of the Royal Laotian Government. American leaders 

became especially concerned that a Communist 

victory in Laos would increase the threat to 

Thailand, Cambodia, and South Vietnam. 

One of the first times the U.S. Seventh Fleet 

provided direct intelligence support to the South 

Vietnamese government occurred in late 1962. 

With the possibility of future U.S. amphibious, 

mine, and coastal patrol operations along the coast, 

Admiral Harry D. Felt, Commander in Chief, Pacific 

(CINCPAC), ordered a study of South Vietnam’s 

beaches. In January 1962 high-speed transport Cook

(APD-130) conducted a survey of beaches from 

the northern provinces of the country near the 

Demilitarized Zone (DMZ) to Vung Tao southeast 

of Saigon. Underwater demolition team (UDT) 

“frogmen” went ashore and gathered information on 

beach gradients, tides, and underwater obstacles. In 

early 1963 Marines from Weiss (APD-135) investigated other potential landing sites along the coast 

but this mission did not go unnoticed by the Viet 

Cong. Guerrillas sniped at the men when they went 

ashore near Danang and later near Vinh Chau in the 

Mekong Delta. 

In 1962 Seventh Fleet reconnaissance planes 

completed the mapping of South Vietnam and 

other areas in Indochina. In addition, the Navy 

upgraded its photo production center at Naval Air 

Station (NAS) Cubi Point to a “Special Fleet Lab.” 

The facility at the Naval Air Station Cubi Point in 

the Philippines and Heavy Photographic Squadron 

61 (VAP-61) kept two photo interpretation teams 

in readiness for emergency Seventh Fleet requests. 

The Navy continued upgrading facilities at Cubi in 

1964 by building a full-fledged photo interpretation 

center—Fleet Intelligence Center Pacific Facility 

(FICPACFAC). Throughout the war, FICPACFAC 

would directly support the Seventh Fleet with 

detailed readouts of enemy installations, defenses, 

and lines of communication and rapid readouts of 

fleet photography of suspect infiltration vessels, 

among other products. 

The primary mission of U.S. naval personnel 

in South Vietnam during the late 1950s and early 

1960s was to serve as advisors and work to improve 

the operational effectiveness of the Vietnam Navy 

(VNN). After approval by Washington in September 

1962, Captain Joseph B. Drachnik, head of the advisory group’s Navy Section, established a two-week 

naval intelligence course for the VNN. Lieutenant 

Commander Philip B. Shepard and Lieutenant (j.g.) 

Ray B. Huttig provided instruction to more than 200 

South Vietnamese officers by mid-1963. •
These RA-3B Skywarrior reconnaissance planes of Heavy Photographic Squadron 61 (VAP-61) operated in conjunction with 

the Special Fleet Lab at Cubi Point Naval Air Station in the Philippines to collect information on North Vietnam’s air defenses.

NHHC Vietnam Collection
8

NHHC Vietnam Collection

A South Vietnamese officer of the Coastal Force uses his binoculars to detect suspicious activity by any of the fishing and 

commercial vessels moving along the shore. 
9

THE QUESTION OF SEABORNE INFILTRATION 

One of the most 

hotly contested 

issues of the 

Vietnam War 

was the extent of North 

Vietnam’s use of the sea to 

transport arms, ammunition, 

and military supplies to Viet 

Cong units along the coast of 

South Vietnam. Early in the 

conflict, the South Vietnamese 

established a Coastal Force, 

often referred to as the “Junk 

Force” for its primary patrol 

vessel. Paramilitary sailors clad 

in black pajama-like uniforms 

and operating from junks all 

along the coast checked the 

identity papers of fishermen 

and other boatmen. During 

1962 and 1963 the Coastal 

Force captured more than 300 

enemy sampans and other 

vessels, and even though most 

were engaged in intracoastal 

movement, they discovered 

only a few boats that had 

begun their journeys in North 

Vietnam or Cambodia. 

Admiral Felt doubted that 

there was significant seaborne 

infiltration from North Vietnam but decided to order 

a one-time patrol effort to affirm or deny its existence. 

Of more importance to him was to give the VNN 

an opportunity for training with the Seventh Fleet. 

In December 1961 U.S. and South Vietnamese units 

inaugurated surface and air patrols from the 17th 

parallel eastward to the Paracel Islands in the South 

China Sea. U.S. and South Vietnamese naval forces 

mounted a similar effort in the Gulf of Thailand to 

evaluate any infiltration from Cambodia. The two 

navies did not discover significant infiltration in 

either of the operational areas so the admiral discontinued the anti-infiltration patrols off South Vietnam 

on 1 August 1962. Captain Drachnik later observed 

Mainland Southeast Asia. 

NHHC Vietnam Collection
10

that “I was convinced in my mind . . . that during 

those years there was no effective infiltration by sea . . 

. and Mr. [Secretary of Defense Robert S.] McNamara 

told me later when I was on his staff in the Pentagon 

that he too was convinced.” 

Ironically, and coincidentally, in 1963 North 

Vietnam launched a major seaborne infiltration 

effort with 50- to 100-ton vessels. North Vietnamese 

trawlers of the 125th Sea Transportation Unit made 

eight trips to South Vietnamese waters in 1963. The 

steel-hulled vessels transported tons of arms and 

ammunition to Viet Cong forces in the Mekong 

Delta and central South Vietnam. Sometimes these 

vessels flew the flag of the People’s Republic of China 

to conceal their origin. Typically, the trawlers sailed 

to points off South Vietnam beyond the patrol 

sectors of the VNN and on moonless nights quickly 

dashed to the beach to offload their cargoes. In other 

cases, the trawlers offloaded their cargoes to waiting 

sampans and smaller vessels. U.S. intelligence agencies, including the Office of Naval Intelligence, later 

determined that the maritime infiltration of war 

materials by these ships increased sixfold from 1963 

to 1964. But the Coastal Force did not discover any 

of the infiltrating ships during that period. 

To determine the source and extent of the 

enemy’s transport of fighting men and war materials 

into the Mekong Delta, in January 1964 Admiral Felt 

dispatched a nine-man Navy team to Saigon. After 

visits with naval advisors and other naval personnel 

in-country, Captain Philip H. Bucklew’s group 

issued their findings, thereafter labeled the “Bucklew 

Report.” The report concluded that the Ho Chi Minh 

Trail was North Vietnam’s primary conduit for infiltration of men and supplies into the delta. Bucklew 

and his team added that in their view, the enemy 

used the sea route only for top priority items and key 

personnel, not high-volume traffic. •

NHHC Vietnam Collection

A Neptune P2V patrol plane inspecting a suspicious junk in the South China Sea. 
A North Vietnamese trawler that attempts to deliver war 

materials to the Viet Cong during the war burns after 

U.S. Navy and U.S. Coast Guard patrol forces intercept 

the ship on the coast of South Vietnam. 

NHHC Vietnam Collection

NHHC Vietnam Collection

A Chinese-supplied AK-47 assault rifle captured by allied 

forces in South Vietnam. 
12

USNI

An EA-3B signals intelligence aircraft of VQ-1. 
13

INTELLIGENCE GATHERING IN LAOS

I

n the wake of President Diem’s assassination by officers of his armed forces 

on 1 November 1963, Hanoi accelerated 

the movement of men and materials into 

South Vietnam via the Ho Chi Minh Trail. To 

secure that corridor North Vietnamese leaders 

ordered attacks on troops of the Royal Laotian 

Government. Alarmed by this development in 

Laos, supposedly neutralized by international 

agreement at Geneva in 1962, Laotian Prime 

Minister Souvanna Phouma authorized the United 

States in May 1964 to conduct low-level aerial 

reconnaissance to gather intelligence on the North 

Vietnamese presence in his country. Washington 

readily agreed to this request because President 

Johnson and Secretary of Defense McNamara 

wanted one more means to pressure Hanoi to 

cease its support of the southern insurgency.

From a military standpoint, Washington needed 

accurate intelligence on both Pathet Lao and North 

Vietnamese capabilities and activities in the Plain 

of Jars in central and eastern Laos and the Ho Chi 

An RA-3B Skywarrior of VAP-62 banks to the right, exposing the camera windows on its underside. 

USNI
A Recce Pilot in Harm’s Way

On 6 June 1964 the Navy lost its first 

reconnaissance pilot and plane in the 

Vietnam War. That day, two officers of 

Light Photographic Squadron 63 (VFP-63), 

Lieutenant Charles F. Klusmann and his 

wingman, Lieutenant Jerry Kuechmann, flew 

their RF-8A Crusaders over Route 7 in Laos. 

This jungle road served as the enemy’s main 

supply line from North Vietnam into the Plain 

of Jars. Klusmann’s squadron mates on 

Kitty Hawk referred to the segment between 

Khang Khay and Ban Ban as “lead alley” 

because Communist antiaircraft guns lined 

the route. 

Trying to capture the best images 

with his onboard camera, Klusmann 

took his chances and dropped down to a 

low level. A hidden 37mm gun suddenly 

opened up and riddled the Crusader. The 

young pilot wrestled the controls to keep 

the heavily damaged plane in the air, but 

northwest of Xieng Khouang all systems 

failed. Klusmann ejected from the doomed 

Crusader and parachuted to the ground, all 

the while under small arms fire from Pathet 

Lao guerrillas below.

Meanwhile, Klusmann’s wingman called 

in search and rescue aircraft. Heavy ground 

fire prevented helicopters from reaching 

the pilot’s position and fixed-wing planes 

that could have suppressed the enemy fire 

were too far away. Enemy troops surrounded 

Klusmann’s hiding place and captured him. 

The Pathet Lao forced the injured officer 

to limp through the steamy, insect-infested 

jungle to a prisoner of war compound. 

In succeeding weeks, he suffered from the 

lack of sufficient or nutritious food and 

medical care while enduring solitary confinement. 

Ultimately, alone and weakened from hunger and 

exposure to the elements, Klusmann was compelled 

to sign a statement damning U.S. foreign policy.

Klusmann, however, did not give up. When the 

guards moved the pilot to another, less closely 

guarded compound, he made an escape attempt. He 

failed and suffered mistreatment for his efforts. But 

shortly afterward, Klusmann and five Laotian and Thai 

prisoners tunneled under the wall of their rudimentary 

hut and snuck past the sentries into the jungle. When 

the group separated to avoid a Communist patrol, 

three of the men disappeared into the forest. Another 

prisoner unwisely entered a village in search of food 

and shelter; Pathet Lao soldiers quickly captured him 

and led him away to an uncertain fate. Finally, on 21 

August Klusmann and his lone companion made it to 

friendly lines near Bouam Long. Lieutenant Klusmann 

proved to be one of only two naval aviators who 

escaped from captivity during the entire conflict. •

NHHC Vietnam Collection

14

Reconnaissance pilot Lieutenant Charles F. Klusmann of VFP-63 

describes his time in captivity and escape from Laos to Admiral Ulysses S. 

Grant Sharp, Commander in Chief, Pacific, left, and Vice Admiral Roy L. 

Johnson, Commander, Seventh Fleet, September 1964. 
15

Minh Trail in the southern “panhandle.” Acting 

swiftly, Admiral Felt ordered the start of joint 

Navy-Air Force Operation Yankee Team on 18 May. 

Carrier Kitty Hawk (CVA-63) and her task group 

immediately deployed to the soon-to-be famous 

Yankee Station at 16 degrees north/110 degrees 

east in the Gulf of Tonkin. Within days, Navy and 

Marine RF-8A Crusader and RA-3B Skywarrior 

reconnaissance planes began executing missions 

over Laos. Naval leaders considered the larger and 

slower Skywarrior the best plane for missions above 

10,000 feet and the smaller and faster Crusader 

for low-level runs. A pair of EA-3Bs of Fleet Air 

Reconnaissance Squadron 1 (VQ-1) based in Japan 

complemented the Yankee Team effort with electronic intelligence collection. 

On the 21st, two days after Air Force units 

inaugurated the operation, a pair of Chance-Vought 

RF-8A aerial reconnaissance planes of Light 

Photographic Squadron 63 (VFP-63) launched from 

Kitty Hawk for the first Navy mission. Gunfire from 

the ground put bullet holes in one plane and set it 

on fire but the naval aviator managed to nurse his 

Crusader safely back to Kitty Hawk. This mission 

demonstrated what would become clear throughout 

the Vietnam War: that gathering naval intelligence 

was hazardous work. 

The enemy drove home that truism on 6 June. 

That day, a North Vietnamese antiaircraft unit 

operating in eastern Laos shot down the RF-8A 

of Lieutenant Charles F. Klusmann. The naval 

aviator had the dubious distinction of being the 

first naval aviator shot down in the long war in 

Southeast Asia. Pathet Lao guerrillas quickly 

captured Klusmann and force-marched him to 

a rudimentary jungle prison camp. After almost 

three months in harsh captivity, the daring pilot 

escaped through the jungle and reached friendly 

lines (see sidebar).

Following the shoot-down of another naval 

aviator soon after Klusmann’s loss, Secretary of 

Defense McNamara reduced the risk to Navy and 

Air Force aerial reconnaissance forces by ordering 

them to fly beyond the range of enemy antiaircraft 

guns in the most heavily defended areas of Laos. This 

action reduced the loss of men and planes thereafter 

but significantly limited the worth of the intelligence 

acquired. Nonetheless, the 198 aerial photographic 

missions completed by Navy aircraft (approximately 

half of all photographic missions) during the Yankee 

Team program convinced Washington that the Ho 

Chi Minh Trail was North Vietnam’s major supply 

line to South Vietnam. •

An RF-8A of VFP-63 passes over Ticonderoga (CVA-14) en 

route to a mission in Laos in late 1964.

NHHC Vietnam Collection
16

USNI

An EC-121 Warning Star and an EA-3B Skywarrior, mainstays of the fleet’s signals intelligence effort in Southeast Asia.
17

COLLECTING INTELLIGENCE ON THE ENEMY’S DOORSTEP

By 1964 American leaders had become 

increasingly concerned about North 

Vietnam’s sponsorship and support of 

the conflict in South Vietnam and the 

possibility of war with Ho Chi Minh’s nation. U.S. 

knowledge of the DRV’s naval forces and coastal 

defenses was limited at that time. To increase the 

store of knowledge and not, incidentally, to put 

additional military pressure on Hanoi to restrain 

its bellicose activities in the rest of Indochina, the 

Johnson administration ordered the Navy to conduct 

Desoto Patrol missions in the Gulf of Tonkin.

The Desoto Patrol, in existence since 1962, 

entailed destroyer patrols along the coasts of China, 

the Soviet Union, North Korea, and North Vietnam. 

Rules of engagement for these missions stipulated 

that the ships approach no closer than 20 miles to the 

target countries. Frequently, Navy EC-121 and EA-3B 

electronic intelligence planes operated at the same 

times and, along with the destroyers, monitored emissions that pinpointed radar station locations ashore. 

Key assets for the Desoto Patrol were Direct 

Support Units (DSU) of the Naval Security Group, 

comprising just a small number of U.S. Sailors 

embarked in the destroyers (other DSUs operated 

from the Seventh Fleet flagship, aircraft carriers, 

and cruisers). These DSUs could simultaneously 

monitor North Vietnamese manual Morse and voice 

transmissions and detect radar emissions. The men, 

usually communications technicians (CTs), worked 

in small, cramped, windowless vans usually tied 

down amidships for a particular mission. The DSU 

embarked in Maddox (DD-731) for a July–August 

1964 patrol (the 18th mission since 1962), for 

example, comprised a Navy officer in charge, (the 

following were either Sailors or Marines) two electronic intelligence specialists, two radio/telephone 

intercept specialists, four manual Morse operators, 

two analysts, two communicators, and a maintenance specialist. The highly trained intelligence 

professionals worked in watches over a 24-hour 

period, which was fortunate because only a few men 

at a time could fit into the cramped van. 

While the DSU gathered intelligence for broader 

national-level and Navy-level use, its primary mission 

was to provide Captain John J. Herrick, the officer 

in tactical command for the Desoto Patrol mission, 

with timely warning of hostile enemy intentions. The 

team monitored North Vietnamese air and coastal 

defense and ship-to-shore as well as ship-to-ship 

communications. As a part of the Critical Intelligence 

Communication (CRITICOMM) system, the DSU 

could send and receive messages of relevance to 

Captain Herrick from the larger and more capable 

NSG stations in the Philippines and South Vietnam. 

In January 1964 Commander, Seventh Fleet Vice 

Admiral Thomas H. Moorer, following guidance 

NHHC Vietnam Collection

Maddox (DD-731) steaming in the Pacific in 1964 several 

months before naval intelligence installed a signals intercept van amidships. 
18

from above, issued revised instructions for future 

Desoto Patrols. He authorized the destroyers to 

approach up to 12 miles from the Communist 

countries. The goal of the missions was broadened 

to require the gathering of “all source intelligence,” 

including electronic, hydrographic, meteorological, and photographic information. Moorer was 

particularly interested in data on the location and 

capabilities of naval and air defense forces. 

That same month, new requirements came from 

another source, Commander, U.S. Military Assistance 

Command, Vietnam (COMUSMACV) General Paul 

D. Harkins, responsible for the covert Operation 

34A. In this program, South Vietnamese commandos 

and sailors operating from Danang in “Nasty”-class 

fast-attack craft provided and maintained by the 

U.S. Navy, carried out sabotage and naval gunfire 

attacks against North Vietnam. Harkins needed a 

better appreciation of North Vietnamese defensive 

capabilities, however, for the program to be effective. 

In response, the Pacific Command tasked Army, Air 

Force, and Navy signals intelligence stations in the 

Philippines and South Vietnam to focus greater attention on the needs of the 34A maritime program. 

NHHC Vietnam Collection

Captain John J. Herrick, Commander, Destroyer Division 192 and the on-scene commander of Maddox’s July–August 

Desoto Patrol in the Gulf of Tonkin, and Commander Herbert L. Ogier, commanding officer of the destroyer. 
19

Admiral Moorer also laid on a Desoto Patrol that 

could approach as close as 8 nautical miles to North 

Vietnam (he later also approved an approach of 4 

miles to offshore islands). The warship was tasked 

with photographing items of military interest, 

locating radar transmitters, and reporting on “junk 

activity” and “Viet Cong supply routes.” From 25 

February to 9 March 1964, destroyer John R. Craig

(DD-885), with Lieutenant Commander Donald 

P. Darnell of the MACV staff on board to ensure 

General Harkins’ needs were satisfied, steamed 

along the North Vietnamese coast without incident. 

The 34A teams had little success in their initial 

operations to the North, in part because they had 

insufficient information on North Vietnamese naval 

and coastal defense forces. Admiral Felt informed 

Washington that the “lack of adequate intelligence 

is a prime factor in the failure of maritime operations.” General William C. Westmoreland, who 

took over from Harkins in June, called for more 

detailed information on North Vietnamese forces 

ashore and fast-attack craft capable of intercepting 

the 34A force during their forthcoming missions 

near the islands of Hon Me, Hon Nieu, and Hon 

Matt. U.S. officials grew increasingly concerned in 

early July when MACV learned that more than a 

dozen Chinese-built Swatow motor gunboats had 

deployed to the southern waters of North Vietnam. 

San Miguel in the Philippines and other shore-based 

signals intelligence sites intercepted numerous 

North Vietnamese reports that spoke of commando 

raids, combat between small boats, and high-speed 

chases along the southern coast. On one occasion 

a Swatow motor gunboat chased a faster “enemy” 

vessel for 45 nautical miles before giving up. 

For the late July Desoto Patrol, the new Seventh 

Fleet commander, Vice Admiral Roy L. Johnson, 

specifically directed the destroyer to locate North 

Vietnamese radar transmitters; chart navigational 

lights, landmarks, and buoys; gather current and 

tide information near river mouths; photograph 

landmarks, islands, and relevant radarscope displays; 

and monitor junk traffic. 

General Westmoreland, however, began to doubt 

the value of the ship-based collection effort and suggested that it should be supplemented by submarine, 

high-altitude aircraft, and patrol plane missions. 

For that reason he did not assign a MACV officer 

to the next operation. Questions about the value 

of the Desoto Patrols came from another quarter, 

Chief of Naval Operations David L. McDonald. He 

wanted to be convinced that Seventh Fleet was not 

just “DeSoto patrolling once a quarter because it 

has been going on for some time.” Moorer, now the 

Pacific Fleet commander, responded that he favored 

the operation for three reasons: 1) the good training 

it provided to the Sailors operating in proximity 

to hostile forces; 2) the importance of highlighting 

the U.S. understanding of “freedom of the seas” in 

international waters; and 3) the intelligence collected 

on a potential enemy nation. Moorer’s boss, Admiral 

Ulysses S. G. Sharp, CINCPAC, endorsed a continuation of the patrol. •

NHHC Vietnam Collection

A pair of Norwegian-built “Nasty”-class fast patrol boats 

(PTF) proceed at high speed a few months before their 

deployment to Danang, South Vietnam, to take part in 

Operation 34A against North Vietnam. 
20

NHHC Vietnam Collection

Vice Admiral Thomas H. Moorer, Commander, Seventh Fleet, speaks to Admiral Ulysses S. Grant Sharp, Commander in 

Chief, Pacific, early in 1964. Both officers pushed for strong U.S. measures against North Vietnam to discourage Hanoi’s 

support of the Viet Cong in South Vietnam. 
21

INTELLIGENCE SUPPORT DURING THE TONKIN GULF INCIDENTS

S

oon after Maddox entered the Gulf of 

Tonkin on 31 July 1964 for her Desoto 

Patrol mission, the signals and communications personnel on board the 

destroyer informed Captain Herrick that the North 

Vietnamese were tracking the ship’s passage. 

Hanoi was also aware that “Nasty”-class fast patrol 

boats (PTFs) of the U.S.-supported 34A maritime 

program had just bombarded targets near Hon Me 

and Hon Nieu. During the next two days, Herrick 

learned from his DSU and from the NSA intercept 

stations at San Miguel and Phu Bai, South Vietnam, 

that the North Vietnamese were concentrating a 

force of P-4 torpedo boats at Hon Me to intercept 

the destroyer as she moved south along the coast. 

This vital information prompted Herrick to order 

a course change on the afternoon of 2 August that 

enabled Maddox to head away from the hostile 

shore. It also made catching the withdrawing 

destroyer and achieving the right angle to launch 

torpedoes difficult for the enemy fast craft. The 

North Vietnamese torpedoes missed their mark 

but return fire from Maddox and from carrier 

Ticonderoga (CVA-14) aircraft that sped to the 

scene damaged all three of the attacking P-4s. Vice 

Admiral Roy Johnson praised the NSG and other 

shore-based cryptologic elements for “absolutely 

invaluable” contributions during the crisis, particularly “in light of the general dearth of COMINT 

available on the DRV Navy not too many months 

ago.” Admiral Moorer endorsed that appraisal, 

observing that “the Gulf of Tonkin operations were 

but an episode . . . of the silent war in the ether 

being continually and persistently being waged 

so well” by America’s cryptologic organizations. 

NSA historian Robert Hanyok, in his exhaustive 

study of U.S. signals and communications intelligence during the Tonkin Gulf incidents, has aptly 

concluded that “the SIGINT community could be 

proud of its efforts that day. . . . Everyone in the 

Pacific command [including Herrick] was aware of 

the approaching attack.” 

Determined not to back down in the face of 

Hanoi’s challenge, President Johnson directed 

resumption of the Desoto Patrol. On 3 August 

Maddox, now accompanied by destroyer Turner Joy

(DD-951), steamed back into the gulf. At midnight 

the South Vietnamese PTF force struck again, shelling a target near Vinh Son. U.S. communications 

intercepts made it clear that Hanoi considered 34A 

and the Desoto Patrol as connected operations. 

Analyses then emanated from the intelligence 

stations in South Vietnam and the Philippines that 

suggested that the North Vietnamese navy planned 

to launch another attack, this time on the night of 

4 August. When Maddox and Turner Joy, then at a 

nighttime steaming area far out in the gulf, picked 

up suspicious radar contacts, they anticipated a 

repeat of the 2 August battle. For a few hours both 

ships took evasive action, called in air support, 

and fired on suspected targets. Neither destroyer 

sustained damage and by morning they had reached 

the fleet operating at the mouth of the gulf. 

Not willing to let this supposed second attack 

go unpunished, President Johnson and Secretary of 

Defense McNamara ordered preparation for reprisal 

air strikes on naval bases and a fuel storage facility in 

North Vietnam. In the meantime Captain Herrick’s 

reports to higher headquarters introduced doubts 

about the reality of the attack. For instance, the 

naval officer suggested that “overeager sonarmen” 

may have reported more enemy torpedoes in the 

water than was possible. Many Maddox and Turner 

Joy crewmen, fleet commanders, and others then 

and now, believed that the ships were attacked that 

night, and ample information existed to support that 
NHHC Vietnam Collection

Constellation (CVA-64), along with Ticonderoga (CVA-14), launch retaliatory air strikes in response to the North 

Vietnamese attack on the destroyer Maddox (DD-731). 
23

appraisal. Nonetheless, that evidence was anything 

but conclusive. 

The President, his Secretary of Defense, and 

the military leaders of Pacific Command, Pacific 

Fleet, and Seventh Fleet then looked to the intelligence community to provide them with “smoking 

gun” evidence of an attack. The NSA and its field 

commands immediately gathered and analyzed 

what they considered to be the relevant intercepts 

and reports. NSA apprised the President and 

subordinate civilian and military leaders in the 

chain of command that the evidence confirmed a 

North Vietnamese attack on the destroyers. Only in 

the last decade has NSA admitted, through publication of Robert Hanyok’s formerly highly classified 

study, that the finding resulted from faulty analysis. 

Another historian of the NSA, Matthew Aid, has 

cogently explained that “under intense political 

pressure, intelligence collectors and analysts will 

more often than not choose as a matter of political 

expediency not to send information to the White 

House that they know will piss off the president 

of the United States.” It is now clear that North 

Vietnamese naval units did not attack Maddox and 

Turner Joy on 4 August 1964. 

Convinced at the time, however, that hostile 

forces had attacked warships of the United States 

on 2 and 4 August, President Johnson ordered 

carriers Ticonderoga and Constellation (CVA-64) 

to launch bombing strikes on 5 August against 

North Vietnamese targets ashore and afloat. More 

importantly, on 7 August, the U.S. House 

of Representatives and the U.S. Senate (with only 

two dissenting votes) passed the Tonkin Gulf 

Resolution empowering President Johnson to fight 

the Vietnam War. •

NHHC Vietnam Collection

An officer gives the launch signal to the pilot of a Coral Sea (CVA-43) A-4 Skyhawk heading for a bombing mission in 

North Vietnam. 
24

USNI

Vice Admiral Rufus L. Taylor, the Director of Naval Intelligence during the early years of the air war against North 

Vietnam. He suspected that the People’s Republic of China was behind Hanoi’s aggressive activities in Indochina. 
25

PREPARATIONS FOR WAR IN SOUTHEAST ASIA 

Communist attacks on Maddox in 

the Gulf of Tonkin in August 1964 

and the killing of American service 

personnel in South Vietnam later in 

the year and in early 1965 convinced American 

military leaders that the outbreak of war was 

imminent. It was apparent that rather than 

buckling under U.S. military pressure, Hanoi had 

decided to take the offensive. CINCPAC noted 

in March 1965 a “shift of communist tactics” 

intended to “bring about the disengagement of 

the U.S. in South Vietnam.” In a prescient statement, Admiral Sharp concluded that the North 

Vietnamese felt that “if they can kill Americans, 

harass U.S. personnel, and destroy U.S. facilities 

the American people will, in time, become so tired 

of the war that we will abandon our efforts there.” 

Chief of Naval Operations Admiral McDonald 

called on naval intelligence for an “honest, hard 

NON-EQUIVOCAL assessment” of enemy intentions.” Rear Admiral Rufus L. Taylor, the Director 

of Naval Intelligence, responded with an appraisal 

that suggested China was emboldened by the 

political disarray in South Vietnam and weak 

U.S. counteractions to Communist attacks. The 

underlying assumption of Taylor’s report was that 

China rather than North Vietnam was the prime 

motivator for bellicose actions in Southeast Asia. 

Taylor considered the Chinese determined to help 

the Vietnamese and Laotian Communists secure 

a victory over the United States and its allies. The 

admiral pointed to the recent buildup of military 

forces in southern China and the delivery of war 

materials to Hanoi as a clear sign of Chinese intentions. The Navy’s top intelligence officer took the 

opportunity to make his own pitch for robust U.S. 

action, observing that “if we think it is important 

to us, as I do, to keep Southeast Asia out of Chinese 

Communist hands, we must commit ourselves to 

extensive hostilities in that area.” 

A year’s experience with the Yankee Team 

aerial reconnaissance program in Laos had enabled 

the Navy’s intelligence establishment to hone its 

procedures for collecting, processing, and disseminating tactical intelligence even before the onset 

of the Rolling Thunder bombing campaign against 

North Vietnam in the spring of 1965. Seventh Fleet 

Commander Vice Admiral Johnson, however, realized that his carrier and surface forces needed even 

more precise information on potential targets and 

enemy air defenses ashore, the area’s geography and 

hydrography, and the operating environment. 

The Fleet Intelligence Center Pacific (FICPAC) in 

Hawaii, employing 270 personnel by 1967, stepped 

up to provide the aviation and surface ship combat 

units with updated maps, charts, targeting aids, pilot 

escape and evasion guides, and computerized orders 

of battle. The center also interpreted aerial reconnaissance imagery and produced an average of 27,000 

photo prints each month in support of photo intelligence reports. The Naval Weather Center on Guam 

produced updated information on the climatological 

and weather characteristics in the Gulf of Tonkin. By 

the start of the Rolling Thunder bombing campaign in 

March 1965, naval intelligence had provided relevant 

and updated materials to the fighting squadrons and 

warships deployed off North Vietnam. 

On the negative side, technology was such in the 

1960s that it might take days for couriers to deliver 

raw photographic and audio information from the 

field, process it (including translating the communications intercepts from Vietnamese to English), 

interpret it, and send the finished product to the 

combat commands. On too many occasions, the 

intelligence product arrived too late for its optimum 

combat use. Excessive compartmentalization by 
26

the intelligence agencies of highly classified and 

sensitive information also sometimes prevented the 

combat commands from receiving a comprehensive 

picture of the enemy situation. 

Much of the information on enemy defenses 

and weather in the operational area that would 

be provided to the Navy’s intelligence analysis 

centers during the war came via the NSA, one of 

whose primary objectives was to “extend the eyes 

of American air surveillance.” The agency’s signals 

intelligence programs “revealed information about 

Vietnamese tracking of hostile and friendly aircraft 

over Laos, North Vietnam and the Gulf of Tonkin, 

SAM [surface-to-air missile] order-of-battle details, 

bomb damage reports, airfield status, and other 

data.” NSA cryptologists gathered information on 

the weather over North Vietnam from intercepts and 

passed it on to naval intelligence and hence the fleet. 

The agency’s reports, called “Songbirds,” relayed 

information on the location of downed fliers and 

attempts by the enemy to capture them. The Navy, 

however, generally found that the intercepts could 

not be translated fast enough for a timely response 

by the fleet’s search and rescue forces. •

NHHC Vietnam Collection

Task Force 77, the Seventh Fleet’s Attack Carrier Striking Force, steams in formation as it prepares for war in the early 

months of 1965.
Navy Art Collection

Refueling at Sea by Walter C. Brightwell. 
NHHC Vietnam Collection

A poststrike photograph of the obliterated thermal power plant at Uong Bi in North Vietnam. A Vigilante assigned to 

RVAH-6 operating from Constellation (CVA-64) captures the image in August 1966.
29

NAVY TACTICAL RECONNAISSANCE 

Along with the aircraft carriers, cruisers, and destroyers that deployed to 

the Gulf of Tonkin and the South 

China Sea in late 1964 and early 1965 

were detachments from Seventh Fleet’s specialized 

aerial reconnaissance squadrons. Units flying 

RF-8 Crusaders, RA-3B Skywarriors, and RA-5C 

Vigilantes photographed potential targets. Once 

those sites received the attention of the attack 

squadrons, the reconnaissance planes photographed the results, called “bomb damage assessments (BDA).” Flying over targets that had recently 

been struck and whose air defense forces were fully 

alerted was risky business. To get the clearest, most 

detailed pictures, the reconnaissance pilots had 

to fly a steady, unflinching course 

over the target even in the face of 

heavy antiaircraft and surface-to-air 

missile fire. Barrett Tillman, an 

authority on naval aviation, has 

aptly observed that “since anything 

worth photographing was likely 

well-defended, the best way to get 

the job done was to get in, get the 

pictures, and get out—fast.” Despite 

this caution, aircrews and planes of 

the photo reconnaissance squadrons 

suffered high casualties. During 

the war the enemy shot down 12 

RA-5Cs and 20 RF-8s, a significant 

loss in the relatively small aerial 

reconnaissance community. The 

enemy killed seven RF-8 pilots and 

captured another five, while U.S. 

search and rescue units plucked 

eight men from the sea or the jungle.

RF-8A and, later in the war, RF-8G Crusaders 

from Light Photographic Squadron 63 (VFP-63), 

nicknamed “Fightin Photo,” were the mainstays 

of the carrier-based tactical reconnaissance force. 

RF-8As employed stationary cameras with 3-inch, 

6-inch, and 12-inch lenses but upgraded RF-8Gs 

introduced panoramic cameras that swept from 

horizon to horizon. Both camera types worked well; 

former Crusader pilot Lieutenant (j.g.) Jay Miller 

related that the cameras rarely failed him. The best 

cameras, planes, and pilots, however, could not 

guarantee successful exploitation of the intelligence 

they captured. Rolling Thunder’s overly restrictive 

rules of engagement required that combat aircraft 

could not strike a SAM battery, for instance, until 

USNI

Members of RVAH-7 inspect damage from enemy fire to one of the squadron’s 

Vigilantes that completed a mission in June 1967. 
30

An RF-8G photoreconnaissance plane (foreground) and its 

F-8 fighter escort operating from Hancock (CVA-19), head 

for a mission in Southeast Asia. 

NHHC Vietnam Collection

the Joint Chiefs of Staff in Washington authorized 

the mission, which, along with the Navy’s need to 

recover the reconnaissance aircraft, process the 

film, interpret the imagery, and launch a reaction 

strike, could take hours if not days. Following 

the advice of their Soviet advisors, the North 

Vietnamese frequently moved their SA-2 surfaceto-air missile battalions, which often negated U.S. 

reconnaissance efforts. 

U.S. intelligence agencies devoted enormous 

resources to collection efforts not only with regard 

to North Vietnam but also the Ho Chi Minh Trail. 

Complementing Navy and Air Force aerial reconnaissance and Army special forces ground surveillance 

operations, the NSA monitored North Vietnamese 

In a MiG’s Sights

With the skies of North Vietnam teeming with MiG-17s 

and MiG-21s, it took courage of the first order for the 

photoreconnaissance pilots of VFP-63 to accomplish 

their missions. On 9 July 1968 Lieutenant William 

Kocar, flying an unarmed RF-8 Crusader, began 

a photo run in the southern panhandle of North 

Vietnam. Defending him against enemy interceptors 

was Lieutenant Commander John B. Nichols III 

piloting an F-8 fighter armed with AIM-9D Sidewinder 

missiles and 20mm guns. Nichols considered Kocar 

“one of the very best F-8 pilots” and already a veteran 

of the air war over Vietnam. 

As Kocar photographed military sites below and 

the pair headed for Vinh, Nichols suddenly spotted a 

MiG-17 closing fast on Kocar’s plane. The fighter pilot 

radioed Kocar to “break left”; he did so immediately 

and without a time-wasting rearward look. Nichols 

soon maneuvered his jet behind the MiG and 

prepared to attack. The first Sidewinder that Nichols 

fired missed the target but spooked the enemy pilot 

into a wrong turn that placed the F-8 1,200 feet 

directly behind the MiG. Compounding this error, the 

North Vietnamese aviator punched in his afterburner 

that presented the heat-seeking AIM-9D missile with 

an almost unavoidable target. Nichols launched his 

second missile into the MiG’s tailpipe and finished off 

the plane with 20mm cannon fire. 

During the dogfight, Kocar had positioned his 

unarmed reconnaissance plane behind Nichols’ to 

keep watch on the latter’s “six.” Kocar wanted the 

fighter pilot to go after another MiG that had flashed 

by during the melee. Low on fuel and ammunition, 

however, Nichols decided they should call it a day. 

Both planes then made it safely out to sea, took on 

fuel from a waiting aerial tanker, and recovered on 

board Ticonderoga. It had been just another day in the 

life of a Navy reconnaissance pilot and his defender 

in the lethal skies of North Vietnam. •

NHHC Vietnam Collection

A Soviet-made MiG-17 in flight. 
31

troop and supply infiltration activity on the trail. In 

late 1964 NSA reported the first major movement 

of troops on the trail when it identified the 325th 

Division of the North Vietnamese Army heading for 

South Vietnam. In October 1967 agency personnel 

intercepted the voice network used by way stations 

on the trail, opening what came to be known as the 

“Vinh Window.” This coup enabled NSA to document 

which enemy units were on the trail, their probable 

destinations in South Vietnam, and their arrival 

times. Unfortunately, the intelligence gathered from 

this source did not provide information that was 

timely or that identified terrain features, routes, or 

kilometer posts that would have facilitated precise 

targeting information for air attacks on truck parks, 

way stations, or troop concentrations. The commanders of the Navy’s carrier force appreciated all the 

intelligence they could get with regard to infiltration 

on the trail but, according to an NSA report, naval 

leaders “made it known that they were ‘very unhappy’ 

with the lack of support and targeting data.”

RA-3B Skywarriors operated by Heavy 

Photographic Squadron 61 (VAP-61, supported 

by the Atlantic Fleet’s VAP-62) flew two-thirds of 

their missions at high altitudes during daylight 

hours. VAP-61 carried out the other third at night, 

when the planes employed low-level 

runs and their specialized infrared 

cameras to document enemy 

vehicular traffic on the trail. Each 

year of the war, RA-3Bs completed 

almost a thousand combat missions. 

VAP-61 also conducted oblique photography of the North Vietnamese 

coast from the DMZ to the 20th 

parallel in support of Task Force 

77’s Sea Dragon naval bombardment 

operation. The reconnaissance unit 

was especially adept at identifying 

river crossings or “choke points” 

where enemy vehicles often bunched 

up and offered the carrier forces 

lucrative targets.

RA-5C Vigilantes proved to be 

the Navy’s most technologically 

advanced tactical reconnaissance 

USNI

USNI

Vigilante pilots of RVAH-12 study maps of North Vietnam 

to identify the areas they plan to photograph in a forthcoming July 1967 operation. 

Camouflaged North Vietnamese trucks moving down the Ho Chi Minh Trail 

photographed by a naval reconnaissance aircraft in January 1970. 
32

The Short, Dangerous Life of the Ghost Squadron 

Disappointed with the Rolling Thunder results, 

Secretary of Defense McNamara concluded in 1967 

that a barrier of acoustic and seismic sensors 

emplaced in the critical passes from North Vietnam 

into Laos and along the Ho Chi Minh Trail could 

seriously disrupt North Vietnamese infiltration 

into South Vietnam. With the Air Force temporarily lacking a number of relevant aircraft for the 

mission, McNamara directed the Navy to make an 

initial effort with its Lockheed SP-2E Neptune patrol 

planes. Accordingly, in February 1967 the Navy 

established Observation Squadron 67 (VO-67).

The Navy assembled, trained, and equipped the 

300-man unit from scratch to meet a November 

1967 operational deadline. The service tried to 

compensate for the lack of training and familiarization time by assigning many senior people to the 

squadron, including a captain, 11 commanders, 

5 lieutenant commanders, and 23 chief petty 

officers. The men worked hard learning techniques 

for precisely dropping sensors but with World War 

II-era Norden bombsites. The first modified SP-2Es, 

redesignated OP-2Es, arrived on schedule at 

Nakhon Phanom Air Base in Thailand. VO-67, in 

time nicknamed the “Ghost Squadron” for its supersecret mission, went into combat soon afterward.

On a typical mission, the nine-man crew flying 

an OP-2E dropped one to three strings of seismic 

detection devices (ADSIDs) or acoustic listening 

devices (acoubuoys; related to sonobuoys used 

against submarines). The acoubuoys were normally 

deployed at 500 feet. With the use of the bombsites, 

NHHC Vietnam Collection

From a base in Thailand, OP-2E Neptunes of VO-67 carried out 

their dangerous sensor-placing missions along the Ho Chi Minh 

Trail in Laos. 

aircraft during the war. Like the Crusaders and 

Skywarriors, Vigilantes carried out intelligence collection flights along likely enemy logistics routes and 

poststrike BDA. The planes recorded imagery (black 

and white and color) with their KS-69 panoramic 

infrared cameras and side-looking radars, and 

electronic emissions with their Passive Electronic 

Countermeasures (PECM) system. The infrared 

cameras, even though they took hours to warm 

up before a mission, proved able to differentiate 

between natural vegetation and vegetation used 

to camouflage trucks, way stations, and pontoon 

bridges. The cameras, with 18-inch lenses, also 

provided horizon-to-horizon coverage. Nighttime 

and foul weather did little to impede a Vigilante’s 

NHHC Vietnam Collection

Crewmen load a camera into an RA-5C Vigilante prior to 

an aerial reconnaissance mission.
33

photographic work. 

Director of Naval Intelligence Rear Admiral 

Rufus L. Taylor related that in a 54-day deployment 

off Vietnam in 1965, Ranger (CVA-61)’s Vigilantes 

carried out 42 reconnaissance missions that resulted 

in the collection of 174,355 linear feet of photography. A combat leader of carrier America (CVA-66) 

reported that 13 of 19 reconnaissance missions captured infrared imagery that helped his strike group 

destroy a number of enemy targets. As another 

example, in April 1966 the equipment carried by 

an RA-5C of Reconnaissance Attack Squadron 13 

(RVAH-13) discovered a well-hidden coal complex 

near Cam Pha, a North Vietnamese port close 

to the border with China. Acting quickly on the 

intelligence, ten carrier planes destroyed the target.

In another instance, this time in 1968, infrared 

images revealed suspicious truck movements around 

a cathedral in Vinh, an unlikely site for such activity. 

A surprise photo run at dawn the next morning by 

Vigilantes of RVAH-1 caught North Vietnamese 

troops moving SA-2 missiles onto the grounds of 

the cathedral. Strike aircraft from Carrier Air Wing 

9 soon followed and destroyed the missile battery 

without damaging the building. 

One of the keys to the accurate and timely 

exploitation of camera footage and taped electronic 

intelligence data captured by the RA-5Cs was the 

Integrated Operational Intelligence Center (IOIC). 

The Navy established computer-enhanced IOICs on 

the Neptunes released their ADSIDs initially at 2,500 

feet and later at a safer 5,000 feet. Once emplaced 

and active, the sensors related the relevant information to the Air Force base at Nakhon Phanom where 

it was stored on a computer and interpreted. The 

command in Thailand then used the analysis to direct 

air strikes against detected North Vietnamese vehicles and troops. Air Force forward air control planes, 

F-4 Phantom fighters, and A-1 Skyraider attack planes 

supported the VO-67 Neptunes on their missions. 

The nature of VO-67’s mission placed the men 

and their planes in great jeopardy. The OP-2Es 

routinely flew at low altitudes in poor weather over 

mountainous and jungle terrain thick with North 

Vietnamese antiaircraft guns. On 11 January 1968 

soon after the start of operations in Laos, the 

squadron lost its executive officer, Commander 

Delbert A. Olson and the other eight men of his crew. 

Their Neptune probably slammed into a cliff on an 

acoubuoy-dropping mission in bad weather.

On 17 February the enemy shot down an OP-2E 

dropping sensors at 500 feet; the nine-man crew 

died in the crash. Little more than a week later, North 

Vietnamese ground fire knocked another Neptune 

out of the sky. The pilot, Commander Paul Milius, 

ordered his seven crewmen to bail out before he left 

the plane; they survived, but he did not. The Navy 

later named Arleigh Burke-class destroyer Milius after 

the brave officer. During this period, antiaircraft fire 

damaged another four OP-2Es.

The Navy held a conference on 18 February to 

determine how to reduce the vulnerability of the 

Neptunes. Thereafter, squadron leaders directed 

that planes make only single passes over a target 

to reduce their to exposure to enemy guns, identify 

alternative target areas, fly at higher altitudes, and 

avoid operating in especially bad weather. In March 

the Navy installed Loran [navigation] Assist Devices 

on the planes enabling the squadron to operate in 

high-threat areas in greater safety. With Air Force 

units then coming online, the Navy disestablished 

VO-67 in July 1968. 

Although Observation Squadron 67 operated for 

only two months and suffered the loss of 20 crewmen 

killed in action and three OP-2E patrol planes, its 

exploits earned it a Presidential Unit Citation. The 

sensors emplaced by the unit helped target enemy 

forces converging on the Marine outpost at Khe Sanh 

and surging down the Ho Chi Minh Trail during the Tet 

Offensive of 1968. Warned by the emplaced sensors, 

Air Force, Navy, and Marine attack squadrons 

dropped more than one hundred thousand tons of 

bombs that decimated North Vietnamese infantry 

units moving south. In this way, VO-67 helped save 

the lives of many American and South Vietnamese 

soldiers and marines. •
A Vigilante recovers on board Kitty Hawk (CVA-63) after completing a flight over North Vietnam in April 1966. 

NHHC Vietnam Collection

the large-deck carriers off Vietnam. In less than ten 

minutes, IOICs could produce photographic prints 

and readouts of vast amounts of information that significantly improved the bombing effectiveness of Task 

Force 77’s carrier planes. In June 1967 the IOIC on 

board nuclear-powered Enterprise (CVAN-65) found 

on photographs captured by RVAH-7 Vigilantes a 

surface-to-air missile battery so well camouflaged 

that it escaped initial detection. But, armed with the 

new analysis, the carrier’s combat squadrons soon 

afterward visited the same site and caught the enemy 

unawares. As U.S. bombs ignited fuel on the ground, 

aerial observers watched as some of the site’s ten SA-2 

missiles exploded or skittered along the ground in 

their death throes. BDA photos taken by following 

Vigilantes confirmed the success of the mission. 

Other aviation detachments operating from 

34 the carriers and from shore bases focused on 

The Fleet Intelligence Center Pacific Facility at Cubi Point 

prepared this especially detailed and annotated prestrike 

image of the thermal power plant at Bac Giang before a 

strike in August 1966. 

USNI
35

the collection of signals intelligence. Fleet Air 

Reconnaissance Squadron 1 (VQ-1), the Navy’s 

largest aviation unit, handled the vital responsibility for collecting signals intelligence from North 

Vietnamese air defense radars. Based at Atsugi Naval 

Air Station, Japan, VQ-1 deployed detachments 

to the carriers and shore bases in Southeast Asia 

throughout the war and also retained responsibility 

for monitoring Soviet, Chinese, and North Korean 

emissions. Naval Security Group communications 

technicians complemented the squadron’s naval 

personnel. During the war the Navy reinforced the 

unit’s initial 13 EA-3B Skywarriors and EC-121M

Warning Stars, the latter converted from Lockheed 

Super Constellation passenger planes, with more 

than 30 EA-3Bs, EKA-3Bs, and E-1Bs, some from the 

Rota, Spain-based VQ-2. The unit focused its efforts 

on the Tonkin Delta of North Vietnam, the DMZ, 

and the Ho Chi Minh Trail.

The primary mission of the airborne intelligence 

squadrons was to provide U.S. combat units with 

almost immediate warnings, and VQ aircrews cumulatively issued thousands of near real-time warnings 

of threats posed by North Vietnamese SAMs, MiGs, 

and antiaircraft artillery. Captain Sidney Wood, an 

intelligence officer with VQ-1 throughout Operation 

Rolling Thunder, later observed that he and his VQ-1 

EC-121 crewmen flew their tedious 10- to 12-hourlong missions in the gulf within sight of North 

Vietnam seven days a week. Wood related how crews 

on the EC-121s, with “six to eight ELINT positions 

and a like number of COMINT positions correlated 

intelligence [on enemy SAM, MiG, and antiaircraft 

threats] in near real time and [provided] it to the U.S. 

aircraft over the beach.” 

As related by William B. Leppert, a former VQ-1 

Enterprise on Yankee Station by R.G. Smith. 

Navy Art Collection 
36

petty officer who flew 38 missions off Vietnam, 

the plane also embarked Russian, Chinese, and 

Vietnamese linguists and personnel to operate 

the KW-7 crypto equipment and a teletype, which 

enabled the plane to send messages to the fleet 

below. Speed was essential, so the VQ-1 crew sent 

their warning messages in clear, unencrypted voice 

with reference to a previously established and dailychanging code word for a reference point ashore. 

For instance, the warning might be “SAM Bullseye 

[cover name for Phuc Yen airfield],” with the range, 

bearing, and time to the surface-to-air missile 

battery protecting the airfield. The Navy awarded 

senior evaluator Lieutenant Charles Templin a 

Distinguished Flying Cross for developing an intelligence picture that helped carrier forces shoot down 

one—and possibly two—enemy MiGs. In 1970 alone 

VQ-1 sent out more than 1,000 such warnings. As 

soon as the plane landed, the crew prepared comprehensive, all source Electronic Warfare Operational 

Reports for use with the next day’s strikes. 

Despite the advanced age of the EC-121s, 

continuous technological upgrades of the aircraft 

enabled their Brigand intercept systems to identify 

and locate radiating enemy Fansong missile guidance radars to within 50 yards. The equipment 

receivers had “astronomical gain” according to one 

former crewman, and also could detect the presence of an enemy radar at 150 miles even when the 

systems were not in full radiation mode. VQ-1 collected and analyzed an enormous number of intercepts—10,000 in 1967 alone—for use by Navy and 

national intelligence organizations. VQ-1 aircraft 

provided 24-hour coverage of key areas in Vietnam 

during periods of crisis. During the Tet Offensive 

of 1968, for instance, a total of five EC-121s and 

EA-3Bs operated daily over the Gulf of Tonkin. As 

an example of the unit’s busy schedule, in 1969, the 

squadron’s detachments in Danang, other bases in 

the region, and several carriers completed 1,587 

missions.

Squadron and NSG personnel who served 

with VQ-1 knew that the enemy could shoot down 

their planes (as occurred in 1969 off the Korean 

peninsula when North Korean MiGs destroyed 

an EC-121 and her 31 crewmen). Enemy fire also 

threatened the shore-based detachments’ aircraft 

and personnel. The July 1967 rocket attack (see 

William B. Leppert, a member of VQ-1 and survivor of an 

enemy attack on his Danang base in July 1967.

Courtesy William B. Leppert

An air intelligence officer listens as a reconnaissance 

pilot, safely on board his carrier after a mission, provides 

a debrief. The information derived will help the air wing 

staff develop a more comprehensive picture of enemy 

targets and defenses.

USNI
CT Duty at “Rocket City” by William B. Leppert

(Reprinted with permission of the author and the publishers of CRYPTOLOG)

When one hears the name Rocket City, places like 

Titusville, Florida, or Houston, Texas, may come to 

mind due to their association with the NASA space 

program. Rocket City, however, had nothing to do 

with America’s space program. It was the name 

given to the U.S. air base at Danang, Vietnam, 

during the Vietnam War, one of the largest U.S. 

bases in South Vietnam. During the years 1965–

1973, there were 87 rocket attacks with a total of 

996 rockets fired against the Danang air base by 

enemy forces. These 996 rockets killed 45 and 

injured 586 Americans. In addition to the number of 

casualties inflicted on U.S. personnel, a total of 30 

aircraft were destroyed and 256 were damaged. So, 

why, you ask, am I presenting this data about the 

rocket attacks against the Danang air base? 

During the six months I served at Danang, there 

were three rocket attacks. The most severe attack 

at Danang during the Vietnam War had occurred 

on 15 July 1967 when the enemy forces fired 83 

rounds of 122mm and 140mm Russian-made 

rockets onto the air base. There were 175 casualties 

during that attack and 44 of them were personnel of 

Det Bravo and VQ-1. Our barracks happened to be 

located about 50 yards from a bomb storage area 

that was ignited by one of the rockets. The bunkers 

we had constructed did not have roofs on them at 

the time, so the shrapnel from the exploding bombs 

rained down into our bunkers. Fortunately, no one 

was killed but our barracks was totally destroyed. 

After the attack, the personnel of Det Bravo were 

transferred to another area located near Danang 

Harbor called Camp Tien Sha. It was near the R&R 

area at China Beach. 

Ron Virgin and I happened to be the two CTs 

[communications technicians] on duty the night of 

the rocket attack on 15 July 1967. We were in the 

communications shack about a mile away from 

our barracks, which was destroyed that night. We 

were fortunate, however, since a piece of shrapnel 

had penetrated the roof of the small structure we 

occupied and landed within a few feet of us.

I was only at Danang for six months of my life 

but it was six months that I will never forget. I am 

proud that I served four years in the Navy and I am 

especially grateful that I was fortunate enough to 

have served my time as a CT with the Naval 

Security Group. •

Chinese-made 122mm rockets that the enemy often employed 

against the airfield and other base facilities at Danang. A Marine 

patrol discovered these weapons in 1968 before they could be 

launched.

NHHC Vietnam Collection Courtesy William B. Leppert

The barracks of VQ-1 at Danang, destroyed during the enemy 

rocket attack of July 1967. 

37
38

sidebar) that wounded 44 VQ-1 personnel, damaged 

four EC-121s, and destroyed squadron barracks and 

support buildings was not the only such incident 

during the war. 

The CIA and the Strategic Air Command 

(SAC) inaugurated operations that complemented 

Navy and Air Force tactical reconnaissance efforts 

with high-altitude photography of North Vietnam. 

Agency crews flying A-12 aircraft at Mach 3 

speeds on “Black Shield” missions and Strategic 

Air Command aviators piloting SR-71 Blackbirds 

(two-seat variants of the A-12) on “Giant Scale” 

operations covered all of North Vietnam. A CIA 

report asserted that the Black Shield program 

“reduced the requirement to expose vulnerable 

[Navy and Air Force tactical] reconnaissance 

aircraft to collect necessary [bomb damage 

assessment] photography and has made it possible 

to assess the status of target systems rather than 

individual targets.” The report went on to stress 

that “our requirement for coverage of the SAM 

defended portion of North Vietnam will not be 

met by any combination of reconnaissance assets 

without inclusion of Black Shield.” 

From 1965 to 1969 NSA deployed to the Western 

Pacific signals intelligence ships Oxford (AGTR-1) 

and Jamestown (AGTR-3), one of which operated in 

the South China Sea at all times. The agency took 

this move in response to Admiral Sharp’s fear for 

the vulnerability of the SIGINT stations in South 

Vietnam and to reinforce the overall collection effort. 

Manning these ships were more than 300 Sailors 

and other personnel, 130 of whom operated from 85 

individual work stations (compared to four or five 

An SR-71 (foreground) and a U-2 high-altitude photoreconnaissance plane that operated in the skies of mainland 

Southeast Asia. 

USNI
39

on a destroyer) to gather strategic-level information 

from North Vietnamese and Cambodian communications systems on military, internal security, and 

naval forces. NSA often used the ships as “firemen,” 

positioning them in areas poorly covered by the 

shore-based sites. The Navy valued the intelligence 

gathered from these ships but wished more of it could 

have been related to the fleet’s tactical needs. •

Jamestown (AGTR-3), along with Oxford (AGTR-1), steamed off Vietnam through much of the war enabling naval and other 

intelligence specialists to intercept enemy communications.

USNI
40

A Soviet-made MiG-21, 17 of which fell to carrier-based F-8 Crusaders and F-4 Phantoms in air-to-air combat during 

the war. 

USNI
41

A HELPING HAND TO HANOI: SINO-SOVIET BLOC MILITARY ASSISTANCE

The war materials, military advisors, 

troops, and diplomatic support 

provided to Hanoi by the Soviet Union 

and the People’s Republic of China were 

significant factors in North Vietnam’s victory over 

the United States and its South Vietnamese ally. 

From 1959 to 1964, hoping to be recognized as 

the leader of the Communist world in its fight with 

American “imperialism,” Mao Zedong championed 

national liberation movements and insurgencies in 

Vietnam, Laos, and other Southeast Asian nations. 

He urged Hanoi to pursue an aggressive strategy 

against America’s ally, the Republic of Vietnam. 

Chinese recoilless rifles, small arms, ammunition, 

and supplies flowed to the Viet Cong via North 

Vietnam. The day after Navy carrier planes executed 

the post-Tonkin Gulf incident retaliatory strike on 

North Vietnam in August 1964, China dispatched 

17 MiG-15 and MiG-17 fighter planes to its southern 

neighbor and provided 36 more in December. 

Throughout the war, the PRC supplied Hanoi with 

roughly 30 percent (a total of $665 million in 1960s 

currency) of its military needs; this assistance 

included aircraft, antiaircraft guns, field artillery, 

armored vehicles, small naval craft, rocket propelled 

grenades, small arms, and ammunition. 

During the course of the war, more than 

320,000 Chinese troops operated antiaircraft guns, 

repaired and rebuilt bombed-out railroads and 

bridges, and constructed coastal fortifications. 

Chinese sources later confirmed that in 1968 alone, 

170,000 Chinese air defense, engineering, minesweeping, and logistic troops operated in North 

Vietnam. U.S. air attacks killed 1,000 Chinese 

military personnel during the war.

China also afforded North Vietnam strategic 

depth. In 1964 the PRC linked its air defense 

network to that of North Vietnam. Vietnamese 

pilots trained in China and periodically fled there 

when U.S. fighter defenses became too lethal or 

American strike aircraft put some of Hanoi’s 

airfields out of action. During the war, Chinese fighters shot down five Navy aircraft and two Air Force 

planes that inadvertently strayed over the island of 

Hainan or southern China. Only one naval aviator 

returned from his mission in these cases; in 1973 

the Chinese government released Lieutenant Robert 

Flynn of Attack Squadron 196 (VA-196) from captivity. Moreover, hundreds of thousands of People’s 

Liberation Army soldiers set up camp in southern 

China, ready to deploy to North Vietnam if Mao 

gave the word. 

The U.S. national intelligence establishment’s 

reports about the Chinese military presence in 

North Vietnam and southern China prompted 

Johnson and McNamara to resist calls for an all-out 

war against North Vietnam. They feared a repeat of 

the PRC’s intervention into the Korean War little 

more than a decade before. 

Succor to North Vietnam also came from North 

Korea. Documents contained in an official North 

Vietnamese historical publication reveal that in 1966 

Pyongyang agreed to provide pilots for a fighter regiment that included two MiG-17 companies and one 

MiG-21 company. Beginning in the spring of 1967, 

North Korean-piloted jets operating from Kep Airfield 

in the Tonkin Delta tangled with American aircraft. 

The North Koreans shot down three U.S. Air Force 

planes for the loss of eight of their own. According 

to postwar reports, North Vietnamese leaders were 

unimpressed with the North Korean performance and 

after a decent interval sent the allied pilots home. 

Because of a bitter ideological fight between the 

PRC and the USSR for leadership of the international 

Communist movement, shortly after ousting 

Premier Nikita Khrushchev from power in October 
An SA-2 Guideline surface-to-air missile and its mobile launcher. The enemy fired thousands of these formidable weapons 

at Navy and Air Force aircraft but antiaircraft artillery and automatic weapons claimed more victims in the skies over 

Indochina. 

Courtesy Richard Mobley 
43

1964 Moscow offered the USSR’s considerable 

resources to Hanoi’s war effort. In February 1965 

the USSR and the DRV signed a formal defense and 

economic cooperation agreement. Soon afterward, 

Moscow deployed an early-warning system to North 

Vietnam, which covered not only that country but 

also the Gulf of Tonkin, Laos, northeast Thailand, 

and northern South Vietnam. CINCPAC’s intel-

ligence staff also identified 16 actual or suspected 

fire control radars positioned near Hanoi and 

on the coast. From mid-1964 to March 1965, the 

Communist countries more than doubled the 

number of antiaircraft guns in Hanoi’s arsenal. 

Approximately 85 percent of Soviet military aid 

went to the North Vietnamese air defense system 

that proved increasingly difficult for U.S. forces to 

penetrate. The Defense Intelligence Agency reported 

in 1970 that North Vietnam then operated 257 

mostly Soviet-supplied combat aircraft; 35 to 40 

SA-2 battalions; 1,847 antiaircraft guns (37mm and 

larger); and 471 fire control, missile control, and 

ground control intercept/early warning radars. 

The mainstay of the enemy’s air defense 

system was the 35-foot, two-stage SA-2 Guideline 

surface-to-air missile that packed a 349-pound highexplosive warhead. American aviators referred to 

the feared weapons as “flying telephone poles.” The 

USSR also provided Hanoi with advanced delta-wing 

MiG-21 fighters. However, Soviet and Chinese pilots 

avoided combat over Vietnam. 

U.S. intelligence knew that at any one time there 

were 2,000 to 3,000 Soviet military advisors (it was 

later learned that 22,000 Soviet military advisors 

served in Vietnam) training the North Vietnamese 

to operate the air defense aircraft, missiles, radars, 

and antiaircraft equipment. Beginning in 1965 

hundreds of North Vietnamese pilots learned both 

in Vietnam and in the USSR how to pilot IL-28 light 

bombers and MiG-17 and MiG-21 fighters. •
44

This image taken in August 1965 by an Air Force photoreconnaissance plane shows in sharp detail command vehicles, 

radar equipment, and two SA-2 missiles on their launchers at a SAM site in North Vietnam. 

USNI
45

THE DEFENSE OF NORTH VIETNAM 

While the Communist countries 

provided Hanoi with an impressive arsenal, they would have 

wasted their resources if the 

North Vietnamese had proven unable to use the 

weapons and equipment effectively. The U.S. intelligence community and America’s air warriors, 

however, grew to respect the ingenuity, flexibility, 

resilience, and determination of their enemy. The 

North Vietnamese exploited the heavy weather

that posed a serious challenge to U.S. intelligence 

gathering in North Vietnam. For instance, the CIA 

reported in 1965 that American high-level reconnaissance of Hanoi was possible only 65 days that 

year. The agency observed further that the weather 

had “a particularly serious impact on satellite 

coverage and, to a lesser degree, upon manned and 

drone reconnaissance coverage.” The CIA analysis 

added that “the major factor limiting high-altitude 

photoreconnaissance is cloud cover of the middle 

latitudes.”

The enemy also exploited restrictive U.S. rules 

of engagement to great effect. The enemy routinely 

positioned SAM batteries and antiaircraft guns in 

populated areas or in proximity to hospitals, foreign 

embassies, prisoner of war camps, sports stadiums, 

and agricultural dikes, which were off-limits to 

attacking American aircraft. The North Vietnamese 

defenders lured U.S. search and rescue helicopters 

into elaborate antiaircraft ambushes. The enemy 

also used deception to complicate air attacks, even 

though the National Photographic Interpretation 

Center concluded from aerial photographs that 

these measures, at least in 1967–1968, had been 

“somewhat successful in diverting air attacks but 

in general their efforts have failed.” On the other 

hand the North Vietnamese developed a radar and 

communication system that within five minutes 

could alert air defense forces nationwide of the 

direction and probable targets of approaching U.S. 

strike formations. Ground control intercept radar 

operators grew adept at vectoring MiG pilots to or 

away from attacking U.S. formations. Fearful of SA-2 

missiles that often emerged from the cloud cover 

to destroy unwary aircraft at high altitudes, many 

American naval aviators chose to approach targets at 

low level. Antiaircraft guns, machine guns, and even 

an odd farmer’s rifle, however, brought down more 

U.S. planes in the war than did SAMs. 

Small Soviet ships loaded with communications 

gear routinely operated in proximity to the U.S. 

warships so they could observe and report on fleet 

operations. Similar ships steamed off Guam to alert 

Hanoi when Air Force B-52 bombers took off for 

their strikes in Indochina. 

The North Vietnamese, with the help of Soviet 

advisors, also proved adept at intercepting U.S. 

communications in part because American battle 

commanders, aircrews, and even radio operators 

Sudden Squall by R.G. Smith.

Navy Art Collection
Aerial reconnaissance in July 1970 discovered these North Vietnamese antiaircraft guns near Thai Binh emplaced on an 

agricultural dike, off-limits to U.S. air attack by the rules of engagement. 

USNI
47

The Chinese launch of a Soviet-designed Styx surface-to-surface missile. U.S. naval leaders were concerned that the Soviet 

Union would provide these weapons to North Vietnam for attacks on the Seventh Fleet. 

USNI

often ignored the requirements of communications security or because encryption technology 

failed to protect the information. The Navy later 

concluded that operational commanders finally, if 

belatedly, impressed on subordinates the importance of communications security because it was 

“not really appreciated at the lower levels” early in 

the war. 

U.S. intelligence also monitored North 

Vietnamese military forces that posed a threat to 

Seventh Fleet. At one point, the CIA assessed that 

“U.S. ships in the Gulf of Tonkin are in range of 

all [North Vietnamese] aircraft. The psychological 

effect of achieving a degree of damage or destruction 

to a U.S. naval ship would probably be considered 

by Hanoi to be worth the risk.” Hanoi took that risk 

only once, with minimal result. In April 1972 a trio 

of MiG-17s attacked destroyer Higbee (DD-806) and 

one of the planes scored a hit on the ship’s stern 

with a 550-pound bomb, wounding four Sailors and 
48

knocking out a gun turret. Seventh Fleet surfaceto-air missiles destroyed two of the attacking MiGs. 

North Vietnamese leaders usually reasoned that the 

odds were low that one of their precious aircraft 

would penetrate the fleet’s defensive screen of 

combat aircraft, ship-based surface-to-air missiles, 

and PIRAZ (positive radar advisory zone) or “Red 

Crown” fleet-alert ships. American intelligence 

worried throughout the war that the Soviet Union 

would provide North Vietnam with surface-tosurface missiles to threaten fleet warships. That only 

happened, however, after the U.S. withdrawal from 

Vietnam when they supplied Hanoi with Komar 

missile boats and Styx antiship missiles. 

When North Vietnamese naval vessels attacked 

destroyer Maddox in August 1964 and throughout 

the war, U.S. naval intelligence paid particular attention to the location and movement of the enemy 

navy’s Swatow motor gunboats and P-4 and P-6 

torpedo boats. On occasion strike aircraft discovered and attacked North Vietnamese naval units that 

had attempted to hide under camouflage but were 

spotted by U.S. reconnaissance aircraft. 

At other times, combat forces foiled attacks by 

enemy vessels with no help from naval intelligence. 

In July 1966, for instance, alert U.S. naval aircraft 

thwarted an attack by three P-4s that targeted guided 

missile destroyer Coontz (DLG-8) and destroyer 

A 5-inch mount on destroyer Mansfield (DD-728) opens fire against a target near Dong Hoi in North Vietnam on 25 

October 1966. 

USNI
49

Rogers (DD-876) steaming 55 miles east of Haiphong. 

Carrier planes sank the trio and American boat crews 

retrieved 19 surviving North Vietnamese sailors from 

the sea. The prisoners provided useful information 

to the U.S. intelligence agencies. In August 1972 a 

squadron of Soviet-built P-6s came out to challenge 

heavy cruiser Newport News (CA-148) and three other 

U.S. warships engaged in a nighttime shore bombardment mission near Haiphong. Carrier aircraft 

dropping Rockeye cluster bombs and warship gunfire 

destroyed all three of the attackers. 

Naval intelligence had difficulty gathering 

precise information on another enemy threat to 

the fleet, coastal artillery. The North Vietnamese 

either emplaced their long-range guns in virtually 

impenetrable caves along the country’s southern 

coastline or frequently moved field artillery batteries to different locations. Timely intelligence, 

however, did alert the U.S. cruisers and American 

and Australian destroyers engaged in the Sea 

Dragon bombardment and coastal patrol program 

to the likely presence of hostile guns in their operating areas. North Vietnamese shell fire hit and

damaged ships and near misses killed and wounded 

a number of Sailors, but enemy coastal guns 

failed to sink a single allied ship during the war. 

Moreover, the Americans 

and Australians carried out 

their operations without 

serious enemy interference. 

The Sea Dragon forces 

severely limited the intracoastal movement of North 

Vietnamese junks, sampans, 

barges, and other waterborne 

logistics craft (WBLCs), pronounced “wiblics.” The allied 

cruisers and destroyers also 

restricted the enemy’s use of 

roads and railroads within 

reach of their guns. •

Captain E.M. Rosenberg (holding pointer), the commanding officer of heavy cruiser 

Canberra (CA-70) engaged in Operation Sea Dragon during May 1967, selects targets 

for his warship’s guns. 

USNI
50

A high-flying SR-71 Blackbird, one of the most capable planes of the U.S. aerial intelligence fleet. 

USNI
51

THE POST-1968 AIR WAR IN NORTH VIETNAM AND LAOS

Despite the cessation on 31 October 

1968 of the Rolling Thunder bombing 

campaign against North Vietnam, 

intelligence of enemy intentions 

and capabilities remained vital. The Strategic 

Air Command redoubled its efforts to inform 

Washington, the Navy, and the other military 

services of the enemy’s compliance or noncompliance with the terms of the cease-fire. SAC’s 

high-flying SR-71 Blackbird aircraft used infrared 

and side-looking radars in addition to conventional 

cameras and signals intelligence equipment in their 

coverage of sites in North Vietnam. An SR-71’s 

sweep could cover a much larger area than that 

of a conventional reconnaissance aircraft. In one 

instance, an SR-71 mission produced a composite 

picture that identified 133 occupied and unoccupied SAM sites in North Vietnam. 

In so-called “Buffalo Hunter” missions, high-level 

and low-level drones operated by the Strategic Air 

Command were dropped from DC-130 planes in 

Thailand; directed over portions of southern North 

Vietnam, Laos, and the Gulf of Tonkin; and recovered 

at Danang, South Vietnam. In contrast to the SR-71s, 

the drones routinely flew as low as 500 feet and 

collected high-resolution images of especially critical 

individual targets. As related by some naval analysts, 

the film from the drone and SR-71 flights “might have 

President Richard M. Nixon and Chairman of the Joint Chiefs of Staff Admiral Thomas H. Moorer on board carrier 

Saratoga (CVA-60) in May 1969. The two leaders operated closely on issues relating to naval operations in North Vietnam.

NHHC Vietnam Collection
52

been of use to the Navy, [but it] never got to the carriers or arrived too late.” It did, however, prove useful 

to the Washington agencies and the fleet intelligence 

centers for interpreting broad trends and enemy 

preparations for offensive actions. 

During these post-Rolling Thunder years, 

unarmed photoreconnaissance planes flew the majority of their missions (as many as 5,000 each year) 

over North Vietnam. President Nixon and National 

Security Advisor Henry A. Kissinger contended that 

Hanoi understood the U.S. need to verify compliance 

with agreements reached in Paris. Hanoi, however, did 

not agree with or ignored this interpretation, since 

North Vietnamese air defense forces often shot at and 

downed reconnaissance planes. 

In November 1968 the enemy fired on 29 Navy 

reconnaissance planes and shot down an RA-5C. In 

response Washington ordered fighter escorts to ride 

“shotgun” on the missions and for the latter to attack 

North Vietnamese antiaircraft and missile sites if 

the enemy fired on the U.S. planes. On occasion 

Navy and Air Force units took the opportunity to 

attack SAM and antiaircraft artillery sites when the 

enemy did not open fire but only “painted” the U.S. 

aircraft with their fire-control radars. MiGs continued to be a threat to reconnaissance aircraft as well. 

On 28 March 1970 Lieutenant Jerome Beaulier and 

his radar intercept officer, Lieutenant Steven Barkley, 

flying an F-4 Phantom, destroyed a MiG-21 that 

menaced U.S. reconnaissance operations in southern 

North Vietnam. 

A few months later, in conjunction with the 

allied invasion of Cambodia (during which tons of 

Communist supplies were captured), Navy and Air 

Force planes hit North Vietnamese logistics sites 

and stores near the passes between North Vietnam 

and the Ho Chi Minh Trail. Both operations set back 

enemy plans for offensives in 1970. In November 

1970 Navy and Air Force tactical aircraft carried 

out a two-day bombing of targets near Hanoi and 

Haiphong in Operation Freedom Bait in order to 

divert enemy attention from a raid to free American 

prisoners at the Son Tay camp in North Vietnam 

(however, the mission failed to discover POWs 

there). U.S. reconnaissance planes continued to 

gather intelligence that North Vietnam was deploying strong military forces and stockpiling military 

stores in southern North Vietnam. Despite this 

evidence of North Vietnamese perfidy, Secretary 

of Defense Melvin R. Laird did not want to hinder 

negotiations in Paris so he disapproved an openended program of “protective reaction” strikes. He 

did authorize one-time attacks in North Vietnam 

and by the end of 1971 U.S. aircraft had conducted 

over 100 such missions. In Operation Proud Deep, 

authorized in late 1971 by President Nixon to 

counter the enemy’s increasing aggressiveness, Navy 

and Air Force planes carried out a five-day bombing 

campaign against military targets below the 20th 

parallel of North Vietnam. 

The Navy sometimes ordered reconnaissance missions in the vicinity of known enemy air defense sites 

in North Vietnam, and when radars at those locations 

locked on the aircraft, attack planes launched strikes. 

This tactic certainly increased the danger to the 

intelligence-gathering units and stretched but did not 

contravene the protective reaction rules of engagement. Air Force General John D. Lavelle, Commander, 

Seventh Air Force, however, went further. Frustrated 

with the limited nature of the U.S. retaliatory 

actions and thinking he had the tacit approval of his 

superiors, he ordered preplanned attacks on North 

Vietnamese SAM and antiaircraft batteries. The 

Secretary of Defense fired him. 

Despite the great danger and difficulty Navy and 

Air Force reconnaissance units experienced operating over North Vietnam and Laos from late 1968 

to late 1971, they provided Washington with ample 

and compelling evidence that the enemy would 

initiate a massive invasion of South Vietnam in 1972. 

Well-trained, well-fed, and armed with Soviet-made 

T-54 tanks, PT-76 armored vehicles, 130mm artillery 

pieces, and other advanced weapons of war, the 

soldiers of the North Vietnamese Army readied 

themselves for a campaign that Hanoi believed 

would finally bring victory. •

54

Operation Market Place [sic] by Eugene Klebe.

Navy Art Collection
55

INTELLIGENCE AND THE WAR ON THE COAST

Long before 1972 and simultaneous 

with the air operations against North 

Vietnam, the U.S. Navy fought alongside 

the other services and America’s allies 

to win the struggle in South Vietnam. The Navy 

launched its first major operations in South 

Vietnam in March 1965 when Seventh Fleet 

landed the 9th Marine Expeditionary Brigade at 

Danang. For the rest of the war, the 1st Marine 

Division and the 3d Marine Division of the III 

Marine Amphibious Force (III MAF) battled North 

Vietnamese Army and Viet Cong troops in the 

northern provinces of the Republic of Vietnam. 

Marine generals reporting to CINCPAC, not Navy 

A Vigilante of RVAH-7 takes on fuel from an A-4 Skyhawk 

after the photo reconnaissance plane completed a mission 

over South Vietnam in April 1966.

NHHC Vietnam Collection USNI 

Cubi Point Naval Air Station in the Philippines hosted the Fleet Intelligence Center Pacific Facility, which provided critical 

support to Task Force 77.
Indochina.

NHHC Vietnam Collection
57

admirals headquartered in Saigon, directed combat 

operations in the I Corps Tactical Zone. Naval 

intelligence units of III MAF organic to the Marine 

units, as well as Pacific Command intelligence 

centers (including Fleet Intelligence Centers at 

Cubi and Pearl Harbor), supplied these fighting 

forces with information relevant to the ground war 

in I Corps and the infiltration of troops into that 

region from North Vietnam and Laos. 

The Navy played a more direct role in countering 

North Vietnam’s seaborne infiltration of supplies 

into South Vietnam’s coastal provinces, a mission 

unanticipated in early 1965. Between 1963 and 1965 

North Vietnam dramatically increased its use of 

the sea to arm and supply Viet Cong forces in South 

Vietnam, even though U.S. intelligence agencies in 

Washington and the military commands in Hawaii 

and Saigon discounted the existence of significant 

seaborne infiltration. 

That all changed on 16 February 1965 when a 

U.S. Army helicopter pilot spied men unloading a 

camouflaged, steel-hulled vessel beached in Vung 

Ro, an isolated bay on South Vietnam’s central 

coast. South Vietnamese air and naval forces soon 

converged on the site. For the next three days 

and nights, the attacking forces fought Viet Cong 

guerrillas for possession of the ship and its cargo. 

After the battle, the South Vietnamese and their 

American military advisors discovered on board 

the captured ship and in lay-down areas ashore 

100 tons of munitions, including 1 million rounds 

of small arms ammunition, more than 3,500 rifles 

and submachine guns, 500 pounds of TNT, 2,000 

mortar rounds, 1,500 grenades, and 1,500 rounds 

of recoilless rifle ammunition. Captured documents confirmed that the ship and the mostly 

Chinese- and Soviet-made war material originated 

in North Vietnam. 

Chinese and North Vietnamese small arms, mortar rounds, rocket propelled grenades, explosives, and other munitions 

recovered after a trawler’s unsuccessful attempt to land supplies in South Vietnam. 

USNI 
Seventh Fleet commander Vice Admiral Paul P. 

“Brick” Blackburn Jr. apprised his superiors that the 

“event at Vung Ro Bay . . . is considered to be positive 

proof that sea infiltration is occurring and raises 

the strong possibility that at least a portion of the 

unconfirmed reports of the past were, in fact, true. 

Sea infiltration into RVN [Republic of Vietnam] is 

now proved.” 

Armed with this confirmation, despite continued 

doubts in Washington and even among naval 

officers in Vietnam, General Westmoreland called 

for establishment of a major allied coastal patrol 

effort. Blackburn’s boss, Admiral Moorer, heartily 

endorsed Westmoreland’s call for action, stating 

that the fleet was “on the scene with the capability 

and . . . we are ready to go.” Wasting no time, on 9 

March Westmoreland flew out to Ranger, flagship 

of Commander Task Force 77, and observed to Rear 

Admiral Roger W. Mehle that “he needed help from 

all the resources in the . . . area in order to beat the 

VC military machine and to inspire or shame the 

Vietnamese, particularly the [navy], into doing a 

better job, since they were about the worst of the three 

services in VN.” Responding to the call, on 11 March 

the Navy inaugurated Market Time, an operation that 

would engage the U.S. Navy and its intelligence community for the duration of the long conflict. 

The U.S. and South Vietnamese forces initially 

deployed all along the 1,200-mile coastline from the 

DMZ to the border with Cambodia in the Gulf of 

Thailand included destroyers, minesweepers, and 

shore-based SP-2H Neptune patrol planes. Carrier 

RA-3B reconnaissance aircraft photographed major 

segments of the coastline. The Navy provided the 

surface forces with additional units, including 

destroyer escorts, Swift boats, patrol gunboats, LSTs, 

and Coast Guard high-endurance and 82-foot cutters. 

The VNN contributed coastal patrol ships and its 

junk fleet. P-5B Marlin seaplanes and eventually P-3A 

Orions flying from bases in South Vietnam and the 

58 Philippines eventually reinforced the air patrol. 

General William C. Westmoreland, Commander, 

U.S. Military Assistance Command, Vietnam 

(COMUSMACV), strides across the flight deck of Ranger

(CVA-61) during his visit to the ship in March 1965.

NHHC Vietnam Collection

An SP-2 Neptune patrol plane of Operation Market Time 

inspects a junk in the South China Sea.

NHHC Vietnam Collection
59

Market Time covered South Vietnam’s maritime 

approaches in three general zones: 1) an air patrol 

sector farthest out to sea; 2) an outer surface barrier 

mounted by large U.S. ships; and 3) an inner, or 

“green-water” barrier patrolled by U.S. and South 

Vietnamese boats and junks. Radar and communications-equipped coastal surveillance centers 

established at Danang, Qui Nhon, Nha Trang, Vung 

Tau, and An Thoi coordinated the overall U.S.-South 

Vietnamese patrol effort. 

Vice Chief of Naval Operations Admiral Horacio 

Rivero suggested that Market Time should be 

directed by the Pacific Fleet rather than “some other 

command, such as COMUSMACV.” Accordingly, 

Seventh Fleet ran the operation until 31 July 1965. 

By then, however, it was clear that since the coastal 

patrol directly supported Westmoreland’s war effort 

in South Vietnam, the Navy subordinate on his staff 

should direct Market Time. Rear Admiral Norvell 

G. Ward, as Chief of the Naval Advisory Group and, 

after 1 April 1966, as Commander Naval Forces, 

Vietnam (COMNAVFORV), took on that responsibility and established the Coastal Surveillance Force 

(Task Force 115). 

The early Market Time experiences of the U.S. 

Navy made it abundantly clear that without precise 

intelligence, the chances of allied air and naval 

forces intercepting the arms-bearing ships of North 

Vietnam’s 125th Naval Transportation Unit were 

slim. The enemy command ultimately operated as 

many as 67 vessels, including 18 trawlers of 8 different classes ranging from 95 to 400 metric tons. 

Off the coast of South Vietnam, a U.S. Swift boat pulls alongside a junk to inspect its cargo and the identification papers of 

its crew.

NHHC Vietnam Collection
These ships normally operated from the port 

of Haiphong, although some intelligence reports 

suggested that at the height of the Rolling Thunder 

campaign, China allowed the North Vietnamese to 

operate from ports on the island of Hainan. Routinely, 

infiltrating trawlers headed east through the narrow 

channel between Hainan and the mainland of China 

steamed southward and far out to sea, and only in 

the dark of night steered a course undetected for the 

South Vietnamese littoral. Market Time forces had 

great difficulty locating and tracking the infiltrators, 

identifying them as North Vietnamese ships, and 

coordinating their capture or destruction. CIA, 

DIA, and NAVFORV intelligence determined from 

documents captured in early 1965 and a prisoner 

interrogated in June that for some time as many as 

two trawlers a month had been delivering supplies to 

VC-controlled areas near the mouths of the Mekong 

River. In June allied forces discovered a large arms 

60 cache in Kien Hoa Province southwest of Saigon. 

A NAVFORV intelligence officer, standing next to a chart identifying the location of various Sino-Soviet bloc merchant 

ships, briefs crewmen of Patrol Squadron 40 who will shortly conduct an airborne patrol along the South Vietnamese coast.

USNI
61

Included in the haul were six Chinese-made flamethrowers. A VC prisoner verified that Kien Hoa had 

become a primary delivery point on the coast. Despite 

this evidence and following the Vung Ro interception, 

not until the last day of 1965 did the patrol forces discover an infiltrating trawler, in this case off the coast 

of An Xuyen in the far south of Vietnam. Knowing he 

had been “made,” the ship’s skipper reversed course 

and aborted his mission. 

One problem with the U.S. interdiction program 

might have been a lax attitude toward communications security. A Naval Security Group investigation 

discovered that some naval officers provided over 

unsecure nets a “wealth of information” on which 

ships and craft formed their patrols, where they 

operated, and where they expected to be in the near 

future. On receiving the NSG report, one commander told his subordinates that he had learned 

more key information from the enemy intercepts of 

U.S. communications than from his own subordinate’s situation reports. 

The naval intelligence community dramatically improved coordination with the operational 

commands in Vietnam, exploited all sources of 

intelligence, and developed a sophisticated analytical 

and interpretive process. Eventually, Market Time 

The Mekong Delta. 

NHHC Vietnam Collection
intelligence officers, using pattern analysis, achieved 

a comprehensive understanding of what routes the 

infiltrating ships would take and what sites on the 

coast of South Vietnam they would attempt to reach. 

Between the spring of 1966 and summer of 1967, 

concrete results began to accompany the coastal 

patrol effort. In May 1966, Market Time forces 

destroyed an infiltrating ship and in June forced 

another trawler to run aground, both on the Mekong 

Delta coast. Recovered from these ships were tons of 

munitions manufactured in China in 1965 and 1966. 

Beginning in November 1966 U.S. and Australian 

ships engaged in Operation Sea Dragon off the coast 

of North Vietnam complemented the Market Time 

patrol by intercepting and destroying scores of junks 

and sampans attempting to move supplies into South 

Vietnam or forcing them to abort their missions. 

On New Year’s Day 1967, Coast Guard cutter Point 

62

Crewmen of a South Vietnamese Coastal Force junk work to put out the fire on a North Vietnamese trawler intercepted by 

allied forces in May 1966. 

USNI
63

Gammon (WPB-82304) got into a running fight with 

an infiltrator, compelling the North Vietnamese 

crew to scuttle their ship. Another crew took similar 

action when Task Force 115 units intercepted their 

trawler off Quang Nhai Province in northern South 

Vietnam in March. 

In a desperate attempt to supply North 

Vietnamese and Viet Cong forces, fighting for survival during the Tet and post-Tet offensives of 1968, 

Hanoi dispatched five trawlers to the south—not 

one of them completed the mission. Allied patrol 

forces destroyed or captured three of the vessels 

and forced the other two to give up their infiltration attempt. 

The U.S. naval command in Saigon enhanced 

the interception effort by providing more timely 

communications intelligence reports to the coastal 

units. Part of Market Time’s success during and 

after 1968 can be attributed to NSA which, through 

intercepts, identified the communication network 

of North Vietnam’s 125th Sea Transportation Unit. 

In 1970 NSA installed equipment in a pair of P-3 

Orion coastal patrol aircraft that enabled the crews 

to home in on the radio frequencies employed by 

infiltrating trawlers. As a result of the allies’ comprehensive counterinfiltration efforts, between March 

1968 and August 1969, not one North Vietnamese 

trawler eluded the Market Time patrol. 

The success of Market Time resulted not only 

from the operational skill and bravery of the allied 

patrol forces and support from the intelligence community but also from the failure of U.S. strategy in 

Southeast Asia. Hanoi discovered it did not need the 

sea to keep up the fight in South Vietnam’s northern 

and central provinces. The massive, multiyear U.S. 

effort to interdict the Ho Chi Minh Trail failed 

to prevent the enemy from exploiting that line of 

communications. Despite the heavy and sustained 

U.S. aerial interdiction campaign, which destroyed 

thousands of enemy trucks and other means of 

transport and killed thousands of enemy troops in 

transit, Hanoi managed to keep its forces in South 

Vietnam armed, supplied, and able to launch one 

major nationwide offensive after another. •

U.S. Coast Guard cutter Point Barnes during a patrol near An Thoi in the Gulf of Thailand. Coast Guard units played a 

major role in Operation Market Time.

USNI
A merchant ship unloads its cargo in Cambodia’s port of Sihanoukville.

Courtesy Lawrence Serra
65

CAMBODIA’S OPEN DOOR: SIHANOUKVILLE

The Johnson administration also made a 

major mistake by allowing Cambodia to 

assert neutrality in the Southeast Asian 

conflict while that country provided 

Communist forces sanctuary in its jungle-covered 

eastern and southern borderlands. Throughout the 

war from these sophisticated supply bases, North 

Vietnamese forces staged major offensives into 

South Vietnam and retreated there for recovery 

from battle, reinforcement, and resupply. 

Moreover, an interpretive failure by the U.S. 

national intelligence establishment for years prevented the Johnson and Nixon administrations from 

shutting down a major Communist source of supply: 

the Cambodian port of Sihanoukville. From 1966 to 

1970 multiple sources of intelligence reported that 

Chinese and other Communist-bloc merchant ships 

routinely unloaded cargoes of arms and other military 

supplies at the port. Cambodian companies then 

loaded trucks with the war material and delivered it to 

designated points on the border with South Vietnam. 

North Vietnamese and Viet Cong units then took 

charge of the stores of rocket propelled grenade 

launchers, AK-47 assault rifles, mortar and rocket 

rounds, and other munitions and transported them to 

their combat units throughout the Mekong Delta. The 

United States could have severed this enemy supply 

line in one day by blockading the port, but blockades 

are an act of war and neither the Johnson nor Nixon 

administrations was prepared to take that step unless 

they had incontrovertible proof that the “neutral” 

Cambodian port served America’s enemy. 

The intelligence staffs of the U.S. military organizations in the operational theater, including those 

of the Pacific Command, MACV, and Naval Forces, 

Vietnam, suspected that Sihanoukville supplied 

the bulk of the enemy’s logistic support in the delta 

and the Saigon area. For many years, however, the 

military commands lacked conclusive proof of the 

extent, and even the existence, of this enemy line of 

communications. Information from agent accounts, 

aerial reconnaissance, communications intercepts, 

and other sources proved fragmentary, unsubstantiated, and sometimes contradictory. 

The military commands responded by intensifying their collection efforts. MACV’s Blackbeard 

collection program integrated information 

from manned aircraft, agents, and intelligence 

teams sent into Cambodia. In the spring of 1968, 

Rear Admiral Kenneth L. Veth (left), who led U.S. naval 

forces in South Vietnam from April 1967 to September 

1968, walks with Captain Paul N. Gray, in charge of 

Operation Game Warden. 

NHHC Vietnam Collection
66

COMNAVFORV Rear Admiral Kenneth L. Veth 

persuaded Seventh Fleet to deploy a submarine 

15 miles off Sihanoukville. From that distant and 

fixed position, however, onboard observers could 

not determine which or how many merchant ships 

actually entered the port. The Naval Security Group 

also mounted an effort to gather signals intelligence 

related to Sihanoukville but local atmospheric 

conditions limited the value of the information. 

 In July 1969, however, a task force of MACV, 

NAVFORV, and Seventh Air Force intelligence analysts concluded that Sihanoukville was a major port 

of entry for enemy supplies and that the Cambodian 

government was complicit in their delivery to the 

enemy. Human intelligence reports made it clear 

that Cambodia was importing far more military 

supplies than were needed by its miniscule armed 

forces. One of the more successful clandestine 

agent networks was “Sunshine Park,” overseen by 

the NAVFORV intelligence chief, Captain Earl F. 

Rectanus. He used agents in Cambodia and periodically sent other spies 10 kilometers into the country’s 

border areas. In supporting Blackbeard, the theater 

commander’s overall collection program, he tasked 

U.S. naval intelligence officers with gathering precise 

information: the infiltration of North Vietnamese 

personnel and equipment through Cambodia; 

enemy base camps; Cambodian government interactions with the enemy; waterway movement from 

Cambodian ports to the South Vietnam border; and 

potential North Vietnamese targets in Cambodia. 

Reports from 34 reliable sources determined 

that eight ships had unloaded 7,500 tons of ordnance 

at the port between October 1966 and July 1969. 

Another six ships were suspected of delivering 

10,500 tons of munitions. The Cambodian armed 

forces required only 700 tons annually. The task 

force also learned from North Vietnamese and Viet 

Cong prisoners, former enemy soldiers in South 

Vietnam, and from 436 reports from agents in 

Cambodia that the enemy moved massive amounts 

of war material into the delta from Cambodia. One 

hundred and thirty-six of these reports alluded to 

Sihanoukville as the point of origin for the material 

and only four as the Ho Chi Minh Trail.

Before 1969, however, the CIA, the DIA, and the 

State Department in Washington did not believe that 

Sihanoukville served as a major entry point for enemy 

war material. A CIA study concluded that “a rigorous 

examination of our intelligence holdings failed to 

unearth any reliable evidence of a significant and 

organized flow of ordnance during 1966–1967.” CIA 

historian Thomas Ahern related that agency analysts 

were besieged by a “welter of raw reports, some of 

them alleging an arms traffic that did not exist for a 

full two years after the first claims to it.” He added, 

“even the best of the reporting, up to the spring of 

1969, was low level and incomplete.” 

Captain Rectanus, head of NAVFORV’s intelligence staff during 1968 and 1969, related that even 

after 50 or more briefings of Washington-based 

intelligence officials, he failed to convince them of 

the credibility of the locally developed information. 

He observed that “the analysts that they [CIA and 

State] sent out there on numerous occasions just 

couldn’t be budged. Now [I don’t know] whether it’s 

because the analysts themselves really didn’t believe 

us, didn’t believe that our analysis was good as it 

was, or whether they were told by Washington.” He 

continued, “the second thing that they could never 

accept is the evidence we had that . . . the actual 

crates and guns that were in Sihanoukville went 

this way and ended up in the delta, which we could 

document. And we fought this battle certainly for 

the time I was in Vietnam, never really successful in 

getting State and CIA to recognize it.”

By mid-1969, even the Washington agencies 

had come to accept the evidence that Sihanoukville 

supplied most of the arms that flowed into the 

delta. Unsure of the reliability of the military’s 

sources of information, the CIA belatedly developed its own agent net in Cambodia. Richard 

Helms, Director of the CIA at the time, wrote in 

his autobiography that “dawn broke in late June 

[1969] when CIA operatives recruited an agent with 

direct access to the bills of lading that provided 
67

documentary evidence on the shipping passing 

through Sihanoukville.” Helms admitted to having 

“egg on our [the CIA’s] collective faces.” The agency 

later concluded that there is “now no doubt that 

elements of the Cambodian Army, acting under 

the authority of Chief of State Sihanouk, have 

supervised the movement of substantial quantities 

of arms and munitions from Sihanoukville to communist forces in South Vietnam.”

The overthrow of Sihanouk by members of his 

armed forces in March 1970 and the subsequent U.S. 

and South Vietnamese invasion of Cambodia erased 

all doubt about the port’s vital worth to Hanoi. In 

December 1970 the CIA reported that its review of 

more than 12,000 pages of captured material (and 32 

cases holding cryptographic equipment) documented 

Sihanouk’s perfidy and Hanoi’s strategic coup.

Between December 1966 and April 1969, ships delivered 21,690 tons of military supplies to Sihanoukville, 

most of which soon found its way into South 

Vietnam. Rectanus later observed that “our analysis 

was 5 percent off of what actually came in through” 

Sihanoukville. DIA historian Michael B. Petersen 

related that the agency received a “blow when it 

was revealed, despite its claims to the contrary, that 

most of the North Vietnamese supplies moving 

A P-3 Orion of Patrol Squadron 1, operating from the airfield at Sangley Point in the Philippines, trails a suspicious vessel in 

the South China Sea in 1971. 

NHHC Vietnam Collection
68

south were coming through the Cambodian port of 

Sihanoukville, not down the Ho Chi Minh Trail.” 

One cannot know if the Johnson or Nixon 

administrations would have taken diplomatic or 

military action against the Sihanouk government 

for enabling North Vietnam’s military use of 

Sihanoukville and other Cambodian territory before 

1970. After the war, however, the President’s Foreign 

Intelligence Advisory Board, headed by Army 

General Bruce Palmer, took the larger intelligence 

community to task for “a major intelligence failure 

which resulted from deficiencies in both intelligence 

collection and analysis.” This failure by the U.S. 

intelligence agencies to develop a more systematic 

and reliable intelligence-gathering process and 

failure to settle their interpretative differences over 

the course of many years poorly served the National 

Command Authority. 

Denied access to Sihanoukville when Sihanouk 

temporarily halted operation of the port in the fall 

of 1969 and after his ouster in the spring of 1970, the 

North Vietnamese resumed their use of trawlers to 

deliver supplies to the Mekong Delta. According to 

a VC prisoner, the enemy’s Central Office for South 

Vietnam (COSVN) established Rear Service Group 

962 for receiving, distributing, and storing seaborne 

munitions in the delta. Hanoi sent 15 trawlers south 

between August 1969 and the end of 1970, and 

all but two of the ships were compelled to return 

home without accomplishing their mission. A single 

trawler probably got through in August 1970 and 

Market Time forces sank another one off Kien Hoa 

Province in November. 

In late 1970 COMNAVFORV changed tactics. 

Previously, Market Time aircraft had to track a 

suspected trawler departing North Vietnam (or 

Hainan) and throughout its passage. Allied rules 

of engagement prohibited the destruction of a ship 

in international waters (beyond South Vietnam’s 

12-mile territorial limit) unless it was positively 

identified as a North Vietnamese ship intent on infiltration. When trawlers discovered they were under 

surveillance, they routinely ended their missions 

in hopes of later successfully evading patrols. The 

U.S. operational approach resulted in an enormous 

expenditure of patrol time to say nothing of wear 

and tear on the planes and crews. 

In the new tactic COMNAVFORV arranged with 

CINCPACFLT for the latter’s naval units to track 

a trawler’s passage sight unseen. Reconnaissance 

planes photographed the ship departing Haiphong 

and passed images to a submarine deployed east 

of the strait between the Chinese mainland and 

Hainan. Then the submarine worked in tandem 

with P-3 Orion patrol planes as the suspected vessel 

headed south. Only when the infiltrator made a dash 

for the coast of South Vietnam did the trailing unit 

notify COMNAVFORV so he could concentrate 

his forces to capture or destroy the ship. A trawler 

managed to evade that surveillance and deliver its 

cargo to a point in An Xuyen Province in March 

1971. In succeeding months, however, the system 

worked as planned. Market Time forces destroyed 

three vessels, one of which was a new SL-8 trawler 

with a carrying capacity of 400 tons. Apparently 

discouraged by this loss, Hanoi did not send another 

ship south for another six months. The most successful application of this tactic occurred in April 1972 

with the sinking of an enemy trawler off the Mekong 

Delta (see sidebar).

Seaborne infiltration increased with the turnover 

of coastal surveillance resources to the Vietnam 

Navy and the departure of U.S. forces from the war 

in 1973, but that development had little strategic 

impact on the war. By 1975 the Ho Chi Minh Trail 

had literally become a logistics superhighway that 

enabled the Communist forces to overwhelm the 

Republic of Vietnam and win the war. • 
Sculpin and the Sinking of an Infiltrating Trawler

In the spring of 1972, the Navy exploited the superb 

tracking ability and stealth of its submarine force to 

interdict seaborne infiltration into South Vietnam. 

Beginning on 10 April, nuclear-powered attack submarine Sculpin (SSN-590), skippered by Commander 

Harold Mathis, tracked a suspected North 

Vietnamese trawler as it exited the Chinese island 

of Hainan and headed south for points unknown. 

Admiral Bernard A. “Chick” Clarey, the Pacific Fleet 

commander, notified MACV headquarters near 

Saigon of the surveillance mission. MACV, in turn, 

assigned operational control of the submarine 

mission to COMNAVFORV, Rear Admiral Robert S. 

Salzer. In coming days the admiral monitored the 

mission almost on a minute-to-minute basis. 

For 11 days and remaining out of sight, the 

submarine followed the infiltrator as she made a 

circuitous passage through the South China Sea, 

along the island of Borneo, up the coast of the 

Malay Peninsula, and into the Gulf of Thailand. 

P-3 Orion patrol planes maintained contact with 

the trawler when the ship entered the “Dangerous 

Ground” (an area about 180 nautical miles wide 

and 300 miles long) and other shallow waters 

unsafe for submarines.

COMNAVFORV Rear Admiral Robert S. Salzer, who 

oversaw the successful tracking and destruction of the 

enemy ship that tried to evade the Market Time patrol in 

April 1972.

USNI

Nuclear-powered attack submarine Sculpin (SSN-590) underway. The ship trailed a trawler from the ship’s point of departure off North Vietnam to the Mekong Delta coast in April 1972. 

NHHC Photo Collection

69
Before the trawler reached the Mekong Delta 

coast of South Vietnam, Salzer insisted that Sculpin 

photograph the ship and positively identify her as 

the one that they had been following from Hainan. 

Commander Charles R. “Chuck” Larson, executive 

officer of Sculpin and future Commander in Chief, 

Pacific, recalled that the commanding officer and 

he informed NAVFORV that “we are absolutely sure” 

about the identity of the ship. Communications intelligence personnel on board the submarine intercepted 

a message from the trawler that made clear the 

enemy was unaware of the submarine trailing her until 

the last hours of the mission. During the passage 

from Hainan, the submarine’s sonarmen became 

intimately familiar with the trawler’s distinctive shaft 

and propeller sounds. Periscope photographs of the 

white-colored trawler confirmed their analysis. 

The trawler finally made a run for the coast 

of South Vietnam. Until disapproved by CINCPAC, 

Admiral John S. McCain Jr. considered ordering 

Sculpin to sink the ship with a torpedo. Nonetheless, 

Rear Admiral Salzer alerted Market Time patrol 

forces, including Vietnam Navy submarine chaser 

Tran Khanh Do (HQ-4) and U.S. destroyer escort 

McMorris (DE-1036), to intercept the ship. On 24 

April in international waters, Tranh Khanh Do hailed 

the trawler, which promptly hoisted the flag of the 

People’s Republic of China and refused to stop. The 

Vietnam Navy warship then opened fire with her 

3-inch guns. Larson recalled that as Sculpin’s officers 

watched the action thorough the submarine’s periscope and the crew observed it in their mess on TV 

monitors, “the trawler exploded and disintegrated as 

its cargo [mostly ammunition] detonated [and] flames 

leaped hundreds of feet in the air.” 

The trawler’s master and navigator were among 

the 16 crewmen who survived the blast and were 

rescued by allied forces. The survivors spoke a 

North Vietnamese dialect, not Chinese. According to 

Larson, the captives verified that they had tried to 

infiltrate guns and ammunition, enough to “supply the 

Viet Cong in IV Corps [the Mekong Delta] for at least 

60 days.” In recognition of Sculpin’s stellar accomplishment, the Republic of Vietnam awarded the ship 

the Cross of Gallantry, the only U.S. submarine to be 

so honored during the war. •

70

72

VC Prisoner by John Steel. 

Navy Art Collection
73

THE NAVAL WAR IN SOUTH VIETNAM 

I

n 1965 and 1966, 

even as Seventh 

Fleet executed 

the air campaign 

against North Vietnam, 

deployed Marine forces 

ashore in South Vietnam’s 

I Corps, and developed 

the Market Time 

coastal patrol, General 

Westmoreland called on 

the Navy to inaugurate 

combat operations in 

the Mekong Delta. This 

lush agricultural region, 

rightly called the “breadbasket of Vietnam,” with 

its 3,000 nautical miles of rivers, canals, and other 

inland waterways, was a logical venue for naval 

operations. French naval forces had successfully 

battled Viet Minh guerrillas there during the First 

Indochina War. The Vietnam Navy’s River Force 

held sway there during the 1950s and early 1960s 

but by 1965 clearly needed help to stem the rising 

Viet Cong tide. The enemy disrupted commercial 

traffic on the waterways, established tax collection points, and undermined the authority of the 

government of the Republic of Vietnam. 

Accordingly, on 18 December 1965 MACV and 

the command’s naval staff established the River 

Patrol Force (Task Force 116) to regain control of 

the Mekong River, its main tributaries, and the Rung 

Sat forest between Saigon and the sea. In Operation 

Game Warden, the task force employed heavily 

armed 32-foot, fiberglass-hulled, Jacuzzi jet pumppowered river patrol boats (PBRs), minesweeping 

boats, and UH-1B “Huey” helicopters to accomplish 

the mission. The Viet Cong resisted fiercely, 

frequently ambushing PBR and minesweeping units, 

but ultimately the Game Warden forces established a 

strong presence on the major rivers. The Sailors, who 

sported black berets, interrupted enemy logistics 

traffic, reasserted the government’s writ, and facilitated the free flow of commerce. 

The Navy’s second major operation in 

South Vietnam evolved in response to General 

Westmoreland’s determination to reinforce Army of 

South Vietnam (ARVN) forces operating in the delta 

with U.S. ground troops. Westmoreland recognized 

that waterway movement of this force was essential, 

since few roads existed in the region. The upshot was 

establishment of the Mobile Riverine Force (MRF)

that consisted of one, and later two, brigades of the 

9th Infantry Division and the Navy’s Riverine Assault 

Force (Task Force 117). The MRF’s major purpose 

was to locate, surround, and destroy the enemy’s 

main force battalions and other large formations. To 

accomplish that task the Navy created a contingent of 

heavily armed and armored river craft that included 

command-communications boats, monitors, armored 

troop transports, and armored support patrol boats. 

Supporting the MRF were teams of Army Security 

River Boat 117 under Attack at Night by John Steel. 

Navy Art Collection 
74

Agency voice intercept and short-range directionfinding teams that worked with naval intelligence field 

officers. In one instance, a team on board the MRF’s 

“flagship” Benewah (APB-35) jammed the radio transmissions of a Viet Cong headquarters and tracked its 

movements, enabling a force of PBRs to locate and 

destroy the enemy command group.

Throughout 1967 the MRF engaged in numerous pitched battles that severely depleted enemy 

strength. During the Tet and post-Tet offensives, the 

joint Army-Navy force moved all about the delta as 

General Westmoreland’s “fire brigade,” decimating 

Viet Cong units and recapturing overrun cities and 

towns. MRF monitors and other combatants and 

Game Warden PBRs also helped keep river supply 

lines open to Marine and Army troops fighting hard 

against the North Vietnamese Army in the northern 

provinces of South Vietnam. 

In the aftermath of the Tet offensives of 1968, 

during which the enemy suffered horrendous casualties 

at the hands of allied forces, the new COMNAVFORV, 

Vice Admiral Elmo R. Zumwalt Jr., with the enthusiastic support of the new COMUSMACV, General 

Creighton W. Abrams Jr., decided on a new strategy 

for the Mekong Delta. Zumwalt concluded that his offshore and river patrol forces had largely accomplished 

the interdiction of enemy resupply traffic along the 

coast and on the major rivers of the delta. 

In Operation Sealords (for Southeast Asia lake, 

ocean, river, delta strategy), the admiral concentrated 

strong naval resources along the border with 

Cambodia and in the delta’s smaller rivers and 

canals. The new approach generated fierce combat, 

since the enemy recognized the peril to the supply 

lines of Viet Cong and North Vietnamese forces deep 

in the delta. When U.S. forces withdrew from the 

A monitor of the Army-Navy Mobile Riverine Force fires at enemy forces ashore during operations in the Mekong Delta.

NHHC Photo Collection
75

war as part of the Vietnamization 

program, the Vietnam Navy and 

the other branches of the South 

Vietnamese armed forces took over 

full control of the mission. The hard 

fighting of American and South 

Vietnamese naval and military forces 

employing the Sealords strategy 

from 1969 to 1973 helped secure the 

Mekong Delta for the government of 

the Republic of Vietnam. The defeat 

of South Vietnam in 1975 occurred 

in the northern and central reaches 

of the country, not in the Mekong 

Delta. •

Vice Admiral Elmo R. Zumwalt Jr., COMNAVFORV from September 1968 

to May 1970 and architect of the successful Sealords anti-infiltration 

campaign, receives information on the enemy situation directly from one of 

his combat officers. 

NHHC Photo Collection

General Creighton W. Abrams Jr., COMUSMACV (left) and Vice Admiral Zumwalt at the ceremony marking the latter’s 

departure from South Vietnam in May 1970. The two leaders worked especially well together.

NHHC Photo Collection
76

A SEAL scans the surroundings during his unit’s intelligence-gathering mission in a Mekong Delta village. 

NHHC Vietnam Collection
77

NAVAL INTELLIGENCE AND THE FIGHT FOR SOUTH VIETNAM 

Vital to allied success in securing the 

Mekong Delta and South Vietnam’s 

waterways was accurate and timely 

intelligence. Gathering that intelligence began in the field, where naval combat 

forces came face-to-face with the enemy. Each day 

of the war, coastal and river patrol, MRF, and naval 

aviation units dispatched operational reports to 

NAVFORV headquarters in Saigon that included 

intelligence information. These commands also 

depended heavily on actionable intelligence to 

carry out their duties. 

The Navy’s SEAL commandos not only used 

tactical intelligence with devastating effect on their 

Communist foes but also gathered information that 

was vital to the operation of the combat commands 

they supported. Despite their Hollywood image, 

SEALs in Vietnam did not set out to engage in heavy 

combat with North Vietnamese and Viet Cong 

troops, even though that occurred often enough, 

but rather to collect intelligence on the location, 

resources, movement, and leadership of enemy 

forces. Few other allied organizations surpassed the 

SEALs in capturing or killing key enemy leaders, 

retrieving battle plans and political documents, and 

gathering human intelligence. 

In one instance, the naval command tasked a 

contingent of SEALs with capturing VC leaders 

reported to be meeting near Phan Thiet, east of 

Saigon. At night on 4 July 1967, several SEALs 

swam ashore and, once they determined the beach 

to be free of enemy lookouts, signaled more special 

warriors embarked in a rubber boat to join them. 

The group captured three Viet Cong leaders, killed 

another who attempted to escape, and gathered 

a trove of political and military papers. The team 

then moved swiftly back to the beach. Protected by 

lively naval gunfire from destroyer Brush (DD-745), 

the ship that had transported them to the location, 

the SEALs safely embarked along with their haul of 

prisoners and documents.

SEALs in the Mekong Delta used different tactics 

to carry out their intelligence-gathering duties. 

Sometimes, small SEAL teams followed up on 

reports locating VC camps deep in the jungle to surprise and snatch their human prey. At other times, 

the SEALs set up ambushes with South Vietnamese 

special forces, knowing that some enemy troops 

would survive the ensuing firefight and provide 

useful information. For instance, in the early 

weeks of the Tet Offensive of 1968, a 60-man South 

Vietnamese Provincial Reconnaissance Unit (PRU) 

led by a SEAL officer killed 20 Viet Cong soldiers 

but captured another 23. Shortly afterward, SEALs 

detained an enemy guerrilla who enabled the unit to 

ambush and kill his battalion’s deputy commander, 

a company commander, three other officers, and 

a reporter from Hanoi apparently seeking news at 

the front. The successful operation foiled a planned 

attack on Binh Thuy, headquarters of the Navy’s 

River Patrol Force. In another operation that year, 

SEALs exploited the information from a VC defector 

to identify more than 100 Communists who had 

infiltrated U.S. combat units and agencies around 

the town of My Tho. 

 In the Phoenix Program, SEALs often teamed 

up with PRUs to capture or kill members of the Viet 

Cong Infrastructure (VCI), identified as enemy military leaders, political operatives, intelligence agents, 

tax collectors, and other key personnel. Exploiting 

information from prisoners, former enemy soldiers, 

and villagers, SEALs and South Vietnamese military, 

police, and internal security forces registered 

significant success in the counterinsurgency 

struggle. Phoenix, a responsibility of the CIA’s 

William Colby, was responsible for the capture of 
78

almost 30,000 members of the VCI. Another 17,000 

former antagonists accepted an amnesty offered by 

the South Vietnamese government. In addition, the 

Phoenix forces killed more than 20,000 Communists 

who fought to resist capture. Hanoi later admitted 

that the Phoenix Program seriously threatened the 

cohesion of their insurgency effort. Unfortunately 

for the allies, sometimes harsh and abusive interrogation practices, extrajudicial killings, and general 

disinterest in the program by the South Vietnamese 

government mitigated much of that success. 

One goal of Vice Admiral Zumwalt’s Sealords 

strategy was to establish a permanent South 

Vietnamese government presence in areas of the 

Mekong Delta long dominated by the enemy. Before 

dispatching Swift boat and other naval forces into 

the Cua Lon, a river in the Ca Mau Peninsula, 

the naval command needed good intelligence on 

physical obstructions that might hinder navigation. 

A SEAL contingent sent to investigate not only 

identified a number of Viet Cong-built barriers in 

the waterway but determined that their destruction 

would not be easy. The barriers proved impervious to air strikes and the SEALs’ own explosives. 

Enlightened by intelligence reports provided by the 

SEALs, allied forces later entering the river employed 

sufficient amounts of explosive to demolish the 

structures. Thereafter, naval operations on the river 

went ahead unhindered.

One of the most dramatic operations of 

the war was an attempt to capture several key 

Communist leaders located on an island near 

Nha Trang on the central coast. It was hoped 

that interrogation of these men would lead to the 

A trio of heavily armed SEALs tries to make headway through the mud as they begin a December 1970 patrol in the Ca Mau 

Peninsula, a region of mangrove swamps and especially difficult terrain that concealed enemy guerrilla units. 

USNI
79

unmasking of an entire network of agents that 

had infiltrated the city. On the dark and moonless 

night of 14 March 1969, Lieutenant (j.g.) Joseph 

“Bob” Kerrey and a squad of SEALs disembarked 

from a small craft, soundlessly scaled a 350-foot 

cliff hand-over-hand, and approached the VC 

camp barefoot to lessen the noise. 

Despite the SEALs’ best efforts, however, an 

enemy sentry saw them and raised the alarm. 

Although badly wounded by a grenade and in pain, 

Kerrey continued to lead the operation until almost 

collapsing from blood loss. His men killed seven 

enemy soldiers and captured others. The intelligence 

gathered from that mission was significant and 

included documents that listed Communist agents 

working in the city. For his heroic leadership under 

fire, Kerrey was awarded the Medal of Honor, the 

first of only three SEALs so recognized during the 

President Richard M. Nixon at the White House ceremony where he presented Lieutenant (j.g.) Joseph R. Kerrey (right) with 

the Medal of Honor for his bravery under fire in an intelligence-gathering mission. In the background is another recipient of 

the nation’s highest honor, Navy Lieutenant Thomas G. Kelley. 

NHHC Photo Collection
80

war. Kerrey demonstrated his qualities of leadership many years later as a Democratic Governor 

and Senator from Nebraska and contender for the 

presidency of the United States. 

The Navy awarded SEAL Team One and SEAL 

Team Two, both of which dispatched platoons 

to Vietnam throughout the war, a total of five 

Presidential Unit citations. The naval warriors killed 

or captured 4,000 enemy leaders and troops. More 

importantly but less quantifiably, SEALs saved 

hundreds of American and South Vietnamese lives 

by alerting allied commands to enemy movements, 

concentrations, and attack plans. The accomplishment did not come cheaply. A total of 48 members 

of the Navy’s special warfare community made the 

ultimate sacrifice. 

The Navy and Marine Corps would have been 

hard-pressed to carry out one of their most important responsibilities in Vietnam—major amphibious 

assaults and smaller raids—without intelligence 

collection by other naval special warfare units, 

specifically, the underwater demolition teams. Much 

like their elders in World War II and the Korean 

War, the UDT frogmen paddled ashore in rubber 

boats or swam to the beach in the dead of night and 

in all kinds of weather to gather precise information 

on the tides, beach gradients, underwater hazards, 

and enemy defenses before fleet leaders gave the 

traditional command to “land the landing force.” 

Often the frogmen deployed ashore from Perch

(APSS-313), Tunny (APSS-282), or Grayback (LPSS574), submarines that were specially configured to 

support naval special warfare. UDT 11 and UDT 

12 frogmen carried out their dangerous mission in 

Starlite, Jackstay, Dagger Thrust, Blue Marlin, and 

scores of other amphibious operations during the 

war. The naval service awarded both units Navy Unit 

Commendations for their combat actions and their 

surveillance of hundreds of miles of South Vietnam’s 

beaches, harbors, and rivers. 

Beginning in June 1966 the Naval Investigative 

Service, a field component of the Office of Naval 

Intelligence, sent its first contingent to work in South 

Vietnam. From 1968 to 1970, 6 officers, 12 enlisted 

personnel, 21 special agents, and 8 Vietnamese served 

with the Naval Investigative Service Office (NISO), 

Vietnam, in Saigon, Danang, and five other locations. 

These in-country operatives focused for the most part 

on criminal investigations of U.S. naval personnel. 

When they had the time, NISO team members 

also worked with South Vietnamese national police 

and intelligence agencies to gain an understanding 

of tactics used by Viet Cong sapper units to infiltrate 

and attack allied military facilities. For instance, 

Lieutenant James Law, NISO Vietnam’s executive 

officer in 1968, spearheaded an effort to document 

Amphibious transport submarine Grayback (LPSS-574), one of several specially configured boats that landed SEAL and 

UDT Sailors on the beach for intelligence-gathering prior to amphibious operations. 

USNI
81

sapper attacks that both succeeded and failed during 

the Tet offensives of 1968 and disseminated his findings throughout MACV. 

NISO also recruited Vietnamese informants 

on U.S. naval installations and in contiguous towns 

and villages to help identify Viet Cong spies among 

the civilian workforce. Despite NISO’s best efforts, 

however, few U.S. military leaders believed they knew 

the identities of the enemy informants in their midst. 

Indeed, it was widely understood by Americans 

during the war that the enemy learned of allied plans 

soon after operational information reached South 

Vietnamese commands. Vice Admiral Zumwalt later 

elaborated: “The VC were also getting a lot of intelligence from people who were supposedly on our side. 

There were two or three officers in the Vietnamese 

Navy that turned out to be a real surprise to all of us, 

that we would have all sworn were loyal to us that 

were actually VC agents.” Captain Rectanus made a 

similar point: “After the war was over, we found even 

some of the most trusted Vietnamese that we thought 

would die for South Vietnam were deep informants 

all along. We were never sure, and I don’t think that 

the [South] Vietnamese themselves were ever sure 

that they weren’t infiltrated.”

The naval intelligence community both in 

Vietnam and the United States focused much attention on one aspect of warfare particularly relevant 

to naval forces operating in South Vietnam’s waterways—mines. These included acoustic-magnetic influence mines using Soviet-designed firing mechanisms 

and mines command-detonated from shore. Viet 

Cong swimmers emplaced limpet mines on the hull 

of aircraft ferry Card that sank the ship at the dock 

in Saigon in May 1964. Other enemy mines exploded 

against merchant ship SS Baton Rouge Victory as she 

transited the river between Saigon and the sea in 

August 1966 and Westchester County (LST-1167) in 

November 1968. The latter action killed or wounded 

52 soldiers and Sailors. Mines sank scores of other 

U.S. and South Vietnamese combat craft as well. 

NAVFORV counted more than 100 incidents involving mines in 1968 alone. The intelligence staffs in 

Saigon, Pearl Harbor, and Washington accomplished 

numerous studies of the problem and their advice 

helped the operating forces devise tactical solutions 

to negate the enemy’s mine campaign. Indeed, despite 

the enemy’s best efforts, mines never denied allied 

forces’ use of the rivers, canals, harbors, and coastal 

waters of South Vietnam. •

A 1,000-pound, Soviet-made contact mine recovered by 

Navy mine countermeasures forces in South Vietnam 

before the enemy could detonate it.

USNI

Westchester County (LST-1167) 11 months before Viet 

Cong swimmers/sappers detonated a mine that caused 

U.S. casualties and severe material damage even though 

they failed to sink the ship. 

NHHC Vietnam Collection
82

Naval intelligence officers of the 3rd Coastal Zone pose for a group photo.

NHF Photo Collection 
83

NILOS IN ACTION 

Also instrumental to the collection of 

intelligence at the operational level 

was the Naval Intelligence Liaison 

Officer. COMNAVFORV assigned 

individual NILOs to many of South Vietnam’s 

provinces. These men gathered information from 

the combat units and human intelligence from captured enemy soldiers, former enemy soldiers, and 

the local population. Deployed early in the war to 

Vietnam, NILOs supported the Market Time and 

Game Warden patrol forces and the Army-Navy 

Mobile Riverine Force. 

Vice Admiral Zumwalt’s aggressive Sealords 

campaign to destroy enemy supply lines emanating 

from Cambodia and base areas deep within the 

Mekong Delta demanded 

accurate and responsive 

intelligence support. 

When the admiral 

withdrew some Swift 

boat units from the 

Market Time patrol 

and armored combat 

craft from the MRF and 

concentrated them in 

key areas of the delta, 

he had his intelligence 

staff put many of the 

seven coastal zones/

riverine zones and 28 

NILOs directly under 

his control. Captain 

Rectanus recognized 

that field intelligence 

officers’ past emphasis 

on advising their local 

commands would not work well for Sealords. He 

asserted firmer and more centralized control to the 

intelligence process. Rectanus directed his subordinates to promptly relay their reports to Saigon 

to help his staff develop comprehensive and timely 

analyses of the enemy situation.

One of Captain Rectanus’ greatest accomplishments was to provide Zumwalt with reliable 

information on what means and routes enemy forces 

used to transport recoilless rifles, rocket propelled 

grenade launchers, small arms, ammunition, and 

medical supplies from the Cambodian border to the 

Viet Cong strongholds in the Ca Mau Peninsula and 

U Minh Forest deep in the delta. Armed with that 

intelligence, Zumwalt’s combat forces ambushed 

Viet Cong guerrillas taken prisoner in the Mekong Delta. Intelligence obtained from men 

such as these was essential to successful allied naval operations.

NHHC Vietnam Collection
84

enemy sampans and human porters making their 

way south along narrow canals and jungle paths. 

Such actions, Rectanus understood, could disrupt 

logistic operations for weeks as the enemy was 

forced to develop new routes through unfamiliar 

villages and terrain.

The Navy had trained Rectanus and other 

members of the intelligence community how to 

collect information using imagery and signals intelligence for a conventional war on Soviet, Chinese, 

and Cuban military forces that might figure prominently in a conventional war, but precious little on a 

counterinsurgency conflict. Few NILOs dispatched 

to South Vietnam early in the war had been 

trained to speak Vietnamese, 

understand ground combat, 

develop networks, or handle 

agents. Surprisingly, fewer than 

25 percent of the officers sent to 

serve as intelligence officers had 

backgrounds in intelligence. The 

standard one year in-country 

tours for U.S. military personnel 

and the constant turnover also 

hampered the mission. Rectanus 

later observed that even at the 

end of his time in Vietnam, “our 

naval intelligence organization 

operated, on a scale of ten, maybe 

at [an] effectiveness of five.” 

The captain developed an 

approach to his mission that 

relied most heavily on human 

intelligence collected by networks of Americans and South 

Vietnamese working together. He 

developed a theater-wide intelligence picture based primarily 

on human intelligence, although 

information from aerial reconnaissance, captured documents, 

and interviews with POWs and 

former enemy soldiers changing 

sides also proved essential. 

Rectanus’ actions certainly pleased in-country 

naval leaders, including his boss. Admiral Zumwalt 

related that Rectanus “had a very good network of 

agents in Cambodia. . . . We were getting, generally, 

very good intelligence. And we knew pretty well 

where to strike; we knew pretty well where the 

major infiltrations were occurring.” Captain Arthur 

Price, commander of Task Force 116, observed that 

because of Rectanus’ efforts, there was “a major 

improvement in the timeliness of agent reports” and 

“a marked increase in both the quality and quantity 

of intelligence received by the Game Warden forces 

from the NILOs.” 

Vietnamese-American Navy Intelligence Office by Marbury Brown.

Navy Art Collection
Zumwalt’s Eyes and Ears

Earl Frank “Rex” Rectanus was key to the success of 

Vice Admiral Zumwalt’s Sealords Campaign, a new 

dynamic approach to winning the naval war in South 

Vietnam. 

Born in 1926 Rectanus joined the Navy in World 

War II as an enlisted Sailor and later earned a commission in the Naval Reserve. Rectanus handled 

a number of increasingly challenging surface navy 

and intelligence billets that well prepared him for 

his duties in Vietnam. He served as assistant naval 

attaché in Moscow at the height of the Cold War, 

followed by an assignment as Deputy Assistant 

Chief of Staff for Operations with the Naval Security 

Group. Rectanus later observed that in that billet, 

“much of our emphasis was placed on trying to 

assist the forces in Vietnam as best we could.” The 

captain then served as an intelligence officer on 

the staff of CINCPAC, Admiral Ulysses S. G. Sharp, 

who directed the air war against North Vietnam. 

Each day, Rectanus briefed the admiral on air 

operations and later recalled that during the two-year 

tour, most days began at 0200 and were “totally 

consumed by Vietnam.” He added, somewhat ruefully, that “in those days, we were talking about the 

tremendous pressure that we were putting on the 

North Vietnamese, how they would soon find out that 

it wasn’t worth the cost to continue the war.” They 

never did find that out. 

Taking over as head of NAVFORV’s intelligence 

section (N-2) in the pivotal spring of 1968, Captain 

Rectanus immediately worked to ensure that his 

subordinates, most of whom had little background 

in counterinsurgency operations and served only 

one-year tours in-country, honed their professional 

skills. One fellow staff officer related that “Rectanus 

kept a good handle on his intelligence officers and 

demanded of them the most rigorous analytical 

standards.” One step he took was to tighten control 

of the in-country naval intelligence process. In the 

past, NILOs and naval intelligence officers assigned 

to the coastal and riverine zones provided their local 

commands with intelligence from external sources 

but rarely developed their own information. Rectanus 

demanded that each NILO become “an active, aggressive collector and analyzer working the trade rather 

than just advising.” The captain organized 180 agents 

into independent collection teams. He also fostered 

a much closer relationship with the intelligence staffs 

of the Vietnam 

Navy, sharing 

sophisticated 

radio equipment and 

even sanitized 

communications intercepts 

with the allied 

service and 

benefitting from 

their knowledge 

of the country, 

its people, and 

the enemy. 

Rectanus 

soon gained an 

appreciation 

of how intelligence could 

be employed 

to best effect on the enemy. When Zumwalt came on 

board in September 1968 as the new COMNAVFORV 

and decided on an offensive against enemy forces in 

the delta, Rectanus was able to provide the admiral 

with an especially precise and accurate picture 

of enemy dispositions, unit strengths, and lines 

of communication. Howard Kerr, Zumwalt’s aide, 

remembered that the admiral had “great confidence 

in what he was told by Rectanus. He’d move on that 

very quickly, and I think it proved to be correct.”

Armed with good intelligence, Zumwalt launched 

his campaign that disrupted enemy supply lines from 

Cambodia, penetrated their base areas deep in the 

mangrove swamps and forests of southern Vietnam, 

and enabled the Vietnam Navy to continue the 

fight when the U.S. Navy withdrew from the conflict 

in 1973. 

In recognition of his major contribution to 

the success of the Sealords campaign, the Navy 

promoted Rectanus to Rear Admiral and named him 

Commander, Naval Intelligence Command in 1969. 

He became the Director of Naval Intelligence in 

Washington in 1971. Rectanus retired from the Navy 

in 1976 but went on to serve as Deputy Assistant 

Secretary of Defense for Intelligence. The consummate naval leader and intelligence professional died 

in 2009.•

The intelligence support provided 

by Earl F. Rectanus (shown here as a 

vice admiral) proved to be one of the 

primary reasons for the success of 

the Sealords campaign.

USNI 

85
86

NILOs, along with riverine and coastal zone 

intelligence officers, formed part of the Naval 

Intelligence Field Organization, Vietnam. Most 

NILOs, about 150 of whom served in Vietnam, 

shared the danger and discomfort of the combat 

units with which they served but, since these men 

often operated alone, they also had to endure 

loneliness and isolation. To collect intelligence, the 

young officers rode armored craft, PBRs, and other 

combat vessels into narrow rivers and canals that 

were subject to sudden, deadly Viet Cong ambushes. 

Communist fire killed NILO Kenneth Tapscott and 

four hours later an enemy bullet shattered the jaw 

of his replacement. In the late 1960s enemy action 

wounded all seven NILOs (two men were double 

recipients of the Purple Heart) who served in the 

Third Riverine Zone. Other NILOs lost limbs or had 

to be evacuated because of tropical diseases. 

NHHC Vietnam Collection

Captain Arthur A. Price, in charge of Operation Game 

Warden, inspects the model of a PBR, his command’s 

primary fighting vessel. 

Comrades in arms: NILOs Lieutenant Ross Peterson (left), Lieutenant William Steshko, and Lieutenant (j.g.) Gregory 

Arthur and Vietnamese intelligence officer Lieutenant Ban.

Courtesy William Steshko
Jack Graf: A Naval Intelligence Hero

In a community that was no stranger to courage under 

fire in Vietnam, John “Jack” Graf stood out. 

Before volunteering for Vietnam duty, Graf served 

for two decades in the Navy as an enlisted Sailor and 

chief petty officer. During 1957 Graf wintered over in 

Antarctica in Operation Deep Freeze. He then took 

a commission as a Limited Duty officer, joined an 

A-3D Skywarrior squadron as a bombardier/navigator 

and focused on air intelligence. But the young officer 

wanted more action, and he got it when he volunteered 

for Vietnam duty. He was assigned as the NILO for An 

Xuyen Province, the most forbidding Viet Cong-held 

base area in the southern Mekong Delta. One of 

the first NILOs in-country, Graf earned a Bronze Star 

with Combat V in 1967 by calling in naval gunfire 

that helped allied forces destroy a North Vietnamese 

trawler attempting to land weapons and ammunition on 

the coast. On another occasion that year, Graf flew as 

an observer on board an Army propeller-driven O-1 Bird 

Dog looking for signs of the enemy. He later related the 

details of his experience on that harrowing day: 

We were taking a good look at a small hamlet 

when the jokers started shooting at us. The pilot 

put in a rocket, then I fired a machine gun, and I 

think I got some good hits. We then came around 

to fire another rocket. We were in the dive when 

the pilot took a hit. He had a startled look on his 

face, then collapsed. I immediately unstrapped, 

reached over, and grabbed him and the stick at 

the same time to get control of the airplane. I 

headed for Ca Mau and started making preparations to make a landing. I would have been in 

good shape except the radios went out and part 

of the controls were gone. I circled and made 

pass after pass, then finally brought the thing in. 

I skidded down the runway, through a fence, and 

came to rest in a rice paddy.

The Navy awarded Lieutenant Graf the 

Distinguished Flying Cross for his bravery and 

coolness under great stress. Over the course of his 

Navy service, Graf also earned a Purple Heart, six 

air medals, and other American and Vietnamese 

decorations. 

In 1969 Graf volunteered for a second tour in 

Vietnam and this time served as a naval advisor and 

intelligence officer in the coastal zone that included 

Saigon and the upper delta. On 15 November 

now-Lieutenant Commander Graf went aloft from his 

base at Vung Tao in an O-1 piloted by Army Captain 

Robert White for an aerial reconnaissance mission. 

Enemy ground fire shot up the Bird Dog, forcing both 

men to parachute from the heavily damaged plane.

Jack Graf, one of the most dedicated and courageous 

NILOs who served in South Vietnam.

NHF Photo Collection

An Army O-1 Bird Dog inspects the area below marked 

by colored smoke before artillery or air strikes are called 

in on the enemy. On one such mission, Graf saved his life 

and that of his wounded pilot through remarkable selfcomposure and flying skill. 

USNI

87
88

Quickly captured and imprisoned in a miserable 

jungle cage, Graf resisted his captors’ torture 

for over three months and then broke out. 

White, who survived captivity, later reported that 

the fearless officer made for a river and jumped 

in with Viet Cong guerrillas hot on his trail. 

Enemy gunfire wounded him and he drowned 

before his pursuers could recapture him. 

Before this fact became known, however, U.S. 

and Vietnamese air, naval, and ground forces 

mounted a month-long, but ultimately unsuccessful, effort to find the officer. Jack Graf’s 

remains were never recovered. 

Robert Melka, a naval intelligence officer who 

served during 1969 with Graf (promoted commander posthumously), penned a fitting epitaph 

for the courageous and dedicated American: “He 

had one ambition—serve his country and do it 

well. That he did, and he put up one helluva good 

fight right to the end.” •

An officer of the armed forces of Vietnam awards 

Graf the Vietnamese Cross of Gallantry. 

NHF Photo Collection

Other men hopped on Army O-1 Bird Dog aircraft to get a better picture of the territory for which 

they were responsible. Some NILOs routinely flew 

three or four missions daily. Enemy fire shot down 

planes carrying NILO Peter Decker three times and 

NILO John “Jack” Graf twice. A midair collision 

with another aircraft killed NILO Al Hollowell.

NILOs in Vietnam did not have access to information sources, later common to the intelligence 

profession, that could help them in their work. As 

related by Peter Decker, operational intelligence 

support to forward units in 1969 meant that the 

“NILO briefed what he could divine from pattern 

analysis and surmise from prisoner interrogation.” 

To accomplish the mission in an isolated post 

demanded that an officer employ professional skill, 

initiative, and adaptability. NILO William Steshko 

observed that “to be on your own with few rules 

and lots of power when the stakes are high is an 

adrenaline rush that cannot be topped.” NILO 

Donald Brady enjoyed the independence: “What a 

great job for a junior officer to be able to pursue the 

war as I saw fit with only general guidance from a 

distant headquarters; and, quite a contrast to my 

Army friends who were operating under a very strict 

and unforgiving command structure.”

Some NILO outposts were remote, austere, 

poorly supplied, and vulnerable to enemy attack. 

NILO John Vinson characterized his advanced tactical support base at Tra Cu (close to the Cambodian 

border) as a “hellhole.” The small riverside complex 

of barges and rudimentary structures lacked all 

amenities and reliable communications and suffered 

North Vietnamese attacks “with appalling regularity.” As Vinson related, the meals were grim, too: 

“The guys ate C-rats or North Vietnamese Army 

rations more often than anything else.” 

Many NILOs relied on Army units for protection, 

berthing, messing, and logistics support, and the 

better NILOs worked to fit in as part of a joint team. 

To get a better understanding of the intelligence 

picture in their area, NILOs reached out to the intelligence personnel of the other services, the CIA, and 
89

the State Department. NILO Nicholas Carbone, for 

instance, during 1969 and 1970 met with Army and 

CIA intelligence personnel, read intelligence reports, 

interviewed defectors and PBR crews, and flew in 

surveillance aircraft to identify enemy crossing 

points on the Saigon River. In addition to supplying 

NAVFORV with information to facilitate a coherent 

assessment of the enemy in the delta, NILOs offered 

tactical intelligence in support of ongoing combat 

operations. NILO Peter Decker said he lived “in the 

realm of the now” so the combat units could know 

what they might encounter and where. As related 

by Dewey Feuerhelm, an intelligence officer with 

Task Force 116, “we needed to know which canal, 

which village, which house, which person, and when 

to strike. How far was the target house/storage site/

person from the insert site? Was there frequent nighttime activity in the area? Were VC known to be in the 

area?” NILOs answered such questions and “became 

a primary source of synthesized intelligence for our 

operational planning.” Without the NILO input, 

Feuerhelm wrote, “TF 116 operations would have 

been significantly degraded.” 

NILO Lawrence Serra, posted to the naval base 

at Ha Tien on the Gulf of Thailand during 1969 

and 1970, later revealed that he was involved in a 

number of sensitive missions after the Cambodian 

military’s overthrow of Sihanouk. Serra related that 

while embarked in a Cambodian naval vessel, he 

negotiated with Cambodian military officers and 

facilitated the transfer to them of U.S. arms. He 

emplaced electronic sensors on likely infiltration 

routes on the border, oversaw a network of agents in 

Cambodia, performed a port survey of Sihanoukville 

Harbor, and accompanied the 9th ARVN Division 

in its sweep of a North Vietnamese base area in 

western Cambodia. In short, NILOs significantly 

enhanced the U.S. Navy’s in-country and cross 

border fight. •

NILO Lawrence Serra operated on both sides of the nearby 

Cambodian border during a time of heavy fighting in the 

remote northwestern corner of the Mekong Delta.

Courtesy Lawrence Serra 

NILO Lawrence Serra went on board this corvette of the 

Cambodian navy in May 1970 to facilitate the transfer of 

arms to pro-American forces in Cambodia.

Courtesy Lawrence Serra 

Haywood Gay, Senior Naval Advisor (left); Serra; and 

Frank Brown, U.S. Army 525th Military Intelligence 

Group, coordinated their intelligence-gathering operations from Ha Tien on the Gulf of Thailand.

Courtesy Lawrence Serra 
90

Photo intelligenceman 3rd Class Charles R. Pearson uses his stereoscopic equipment to analyze an aerial image of an 

enemy site in Vietnam. 

NHHC Vietnam Collection
91

INTELLIGENCE IN THE LINEBACKER CAMPAIGN

I

n the spring of 1972, the leadership in Hanoi 

concluded that the time was ripe for a massive 

invasion of South Vietnam. The United 

States had withdrawn all but a few thousand 

military advisors and the staying power of the South 

Vietnamese armed forces was suspect. On 30 March 

enemy divisions launched powerful attacks across the 

DMZ into Central Vietnam, near Pleiku and Kontum, 

and against An Loc only a few miles north of Saigon. 

The Easter Offensive violated the terms of earlier U.S.-

North Vietnamese diplomatic understandings and 

posed the Nixon administration with hard choices: 

let America’s allies fend for themselves and probably 

suffer defeat or reenter the war in force. 

Choosing the latter option, President Nixon 

ordered full-scale air and naval support to South 

Vietnam and resumption of the bombing of North 

Vietnam. B-52 bombers and tactical aircraft soon 

appeared over the battlefields of South Vietnam in 

support of hard-pressed ARVN units. Every day as 

many as 20 Seventh Fleet cruisers and destroyers 

armed with 8-inch and 5-inch guns ranged the coast 

of I Corps, raining fire down on advancing enemy 

units. In mid-April, B-52s, carrier aircraft, and 

Seventh Fleet warships carried out surprise strikes 

against targets near Haiphong. The naval intelligence 

community responded with alacrity. The Naval 

Security Group increased its DSUs on board Seventh 

Fleet ships from 6 to an unprecedented 20. These 

elements provided the fleet and national command 

authority with timely signals and communications 

intelligence support. The newly established Fleet 

Ocean Surveillance Information Facility, based at 

Kami Seya, Japan, kept the fleet well informed about 

the movements of foreign warships and merchantmen off Indochina.

FICPACFAC at Cubi Point in the Philippines 

proved especially valuable to the Navy in 1972, 

producing and disseminating information related to 

the air and naval bombardment operations against 

North Vietnam. The command operated around 

the clock processing raw intelligence photography, 

interpreting it, and using it to prepare targeting lists. 

Dozens of photo interpreters (PIs) in the Philippines 

scanned miles of film to discern the movement of 

enemy logistics vessels and trawlers and fixed targets 

such as bridges, rail lines, antiaircraft guns, SAM 

batteries, and munitions depots. Commander Blake 

Field, FICPACFAC’s officer in charge during this 

period, remembered that photo interpreters beginning their shift had to “literally drag the off-going 

PIs from the light tables.” 

The command’s Linebacker Analysis Group 

processed film from as many as ten daily reconnaissance missions and produced weekly reports 

on the results of air interdiction operations and 

potential strike targets. FICPACFAC also provided 

the Seventh Fleet’s coastal bombardment ships, 

which received an average of 1,500 rounds of North 

Vietnamese counterbattery fire each month, with 

detailed information on enemy coastal defense sites. 

While some Seventh Fleet recipients of the command’s intelligence found hard copy products that 

had to be couriered out to sea untimely, Commander 

Field observed that “nowhere else in the intelligence 

community could a man spot a target, have it verified, have a strike called on it, and then in a day or so 

see the strike results.”

With the hard fighting of South Vietnamese 

troops and their American advisors, by the summer 

of 1972 the combined forces had blunted each of the 

Communist drives. During this period the Nixon 

administration deployed a total of six aircraft carrier 

groups to the Gulf of Tonkin and land-based bomber 

and attack squadrons to airfields in Guam, Thailand, 

and South Vietnam. 
NHHC Vietnam Collection

Ordnancemen attach sea mines to a Coral Sea Corsair prior to the mining of Haiphong by Navy and Marine attack squadrons on 9 May 1972. 
93

On 9 May nine Coral Sea (CVA-43) Corsairs 

and Intruders led by Commander Roger Sheets 

seeded the approaches to Haiphong with powerful 

sea mines. Over 85 percent of North Vietnam’s 

supply of surface-to-air missiles, tanks, heavy artillery, and fuel entered the country via Haiphong. In 

succeeding weeks additional naval aircraft mined 

the other ports of North Vietnam. In Linebacker 

I that began on 10 May, massed U.S. carrier and 

land-based air forces employed new precisionguided munitions in a punishing effort to interdict 

the enemy supply lines to South Vietnam. On 

that opening day alone, U.S. fighters shot down 

11 MiGs. Lieutenants Randall Cunningham and 

William Driscoll, graduates of the Navy’s famed 

Top Gun school, became the war’s first aces that 

day when they bagged the last of their five kills. 

The punishing U.S. air and sea campaign, the 

failure of the Easter Offensive in South Vietnam, 

and waning Soviet and Chinese support persuaded 

the North Vietnamese to negotiate seriously with 

U.S. diplomats. Sensing a more cooperative spirit 

on the other side, on 23 October President Nixon 

ended bombing north of the 20th parallel in North 

Vietnam. Opposition to the likely terms of a ceasefire agreement by America’s South Vietnamese ally 

as well as second thoughts by the leaders in Hanoi 

and Washington, however, dashed hopes for a 

settlement. 

Exasperated with the course of events and 

determined to end the conflict, on 18 December 

Nixon ordered Linebacker II, sometimes referred to 

as the “Christmas Bombing” of North Vietnam. B-52 

bombers dropped their huge bomb loads, for the first 

time in the war, in close proximity to Haiphong and 

the North Vietnamese capital. Enemy air defenses 

downed 15 Super Fortresses during the 11-day operation but the big bombers carried out their massive 

strikes in the heart of North Vietnam. Eventually, 

enemy supplies of surface-to-air missiles, the only 

real threat to the bomber fleet, dried up. Finally 

convinced that the disadvantages of continued 

military struggle outweighed the advantages, North 

Vietnamese diplomats took up serious negotiations, 

which included the release of all American prisoners 

of war. On 27 January 1973 the United States and 

the other belligerents signed the Paris Agreement on 

Ending the War and Restoring Peace in Vietnam. •

NHHC Vietnam Collection 

A pair of F-4 Phantoms from Enterprise’s VF-92 in the skies over Vietnam. Phantoms were the workhorses of Task Force 77 

and claimed 38 MiGs and other enemy aircraft in air-to-air combat during the war.
94

A photo interpreter at work. 

USNI 
95

CONCLUSION

I

n the Vietnam War the U.S. naval intelligence 

establishment accomplished its primary 

mission of arming Navy operational forces 

with information that, for the most part, 

improved their battle performance, understanding 

of the enemy, and prospects for survival in combat. 

From the start of major combat operations 

in 1964 and 1965, the carrier- and shore-based 

intelligence-gathering squadrons presented the 

National Command Authority with a reasonably 

accurate picture of North Vietnam’s air and coastal 

defense forces, activities in central and southern 

Laos, military assistance from the Sino-Soviet 

bloc, and the buildup of ground forces in southern 

China. The communications and signals intercept 

personnel operating at bases in the Philippines and 

South Vietnam and on the ships and aircraft of 

the Seventh Fleet provided destroyer Maddox with 

timely warning of an impending attack by North 

Vietnamese naval forces on 2 August 1964. Less 

praiseworthy, NSG and its parent National Security 

Agency erred in telling President Johnson that the 

enemy navy had attacked Maddox and Turner Joy on 

the night of 4 August. 

The naval intelligence units in support of 

the Rolling Thunder bombing campaign kept 

Washington informed of the steady buildup of 

increasingly effective and deadly North Vietnamese 

MiGs, surface-to-air missile batteries, high-altitude 

antiaircraft artillery, and sophisticated air defense 

radars. Naval intelligence also routinely helped the 

carrier and naval bombardment forces avoid the 

most dangerous defensive concentrations in North 

Vietnam and Laos. The RF-8s, RA-3Bs, RA-5Cs, 

EA-3Bs, EC-121Ms, and other intelligence-gathering 

aircraft employed infrared and wide-angle cameras, 

night vision devices, radars, electronic intercept, 

and other advanced equipment to great effect. The 

OP-2E Neptune proved unequal to the critical task 

given VO-67, but the squadron’s personnel more 

than compensated for that with their courage and 

dedication to the mission. Given the technology of 

the time, the product of the intelligence centers in 

Hawaii and the Philippines and the IOICs on board 

Seventh Fleet carriers got to the operators in reasonable time for them to act on it. 

From 1965 to 1968 Navy attack squadrons, along 

with Air Force bombing units, destroyed most of 

North Vietnam’s rail and highway bridges, fuel 

storage facilities, and thermal power plants, and 

decimated the enemy’s truck fleet on the Ho Chi 

Minh Trail. Despite this deluge of fire from the air 

and from the sea, Rolling Thunder failed to compel 

Hanoi to end the war or stop the flow of troops and 

supplies into South Vietnam. While the Navy and 

the Air Force cannot be absolved of responsibility, 

that failure resulted primarily from a faulty analysis 

by President Johnson and Secretary of Defense 

McNamara of North Vietnam’s will and capability 

to resist American military power. U.S. air and naval 

power proved more effective in defeating the enemy’s 

Easter Offensive of 1972 and with the Linebacker 

operations compelling Hanoi to agree to terms 

ending the war. 

A flawed U.S. national strategy influenced the 

failure to defeat North Vietnam’s seaborne infiltration of war materials into South Vietnam. Between 

1965 and 1972 the U.S. Navy, the U.S. Coast 

Guard, and the Vietnam Navy mounted the Market 

Time coastal patrol that, with few exceptions, 

severely limited, and at times completely stopped, 

enemy trawlers from delivering their cargoes of 

weapons and ammunition to North Vietnamese 

and Viet Cong troops. Naval intelligence figured 

prominently in this successful operation. But 

President Johnson’s unwillingness to challenge the 
96

false “neutrality” of Prince Sihanouk’s Cambodia 

simply allowed the enemy to skirt the allied patrol 

and offload war materials at Sihanoukville for 

subsequent movement into the Mekong Delta. The 

military intelligence organizations in Hawaii and 

Saigon, including NAVFORV’s intelligence staff, 

correctly identified Sihanoukville’s importance 

to the enemy but failed to develop a case strong 

enough to convince the doubters at CIA, DIA, and 

the State Department in Washington. 

Naval intelligence support for the war effort in 

South Vietnam from 1965 to 1968 helped enable the 

River Patrol Force and the Mobile Riverine Force 

to secure the country’s major waterways, defeat 

the enemy’s main force units in the Mekong Delta, 

and carry out Navy-Marine amphibious operations 

on the coast. SEAL and UDT units, headquarters 

intelligence staffs, and individual naval intelligence 

liaison officers sometimes made mistakes in the collection of tactical intelligence. Over time, however, 

these Sailors, who frequently fought face-to-face 

with the enemy, became especially skilled at their 

work. The intelligence community’s provision of 

accurate and timely intelligence made possible Vice 

Admiral Zumwalt’s audacious and energetically 

executed Sealords campaign that strengthened the 

South Vietnamese government’s presence in the 

Mekong Delta for the remainder of the war. The 

enemy’s success infiltrating the allied commands 

and the lax American attitude toward communications security tempered the generally positive 

in-country intelligence effort. 

Key to the operational and tactical successes 

of naval forces in the Vietnam War were the 

intelligence-gathering Sailors who served in the 

reconnaissance planes and warships, headquarters 

staffs, and the Pacific intelligence centers and the 

SEALs, UDT frogmen, and NILOs who operated in 

the hot, wet, insect-infested, and war-torn Mekong 

Delta. Thousands of naval personnel served with 

distinction in support of the Navy’s intelligence 

effort in Southeast Asia: reconnaissance aircrewmen 

like Charles Klusmann, who endured harsh enemy 

captivity; William Kocar, who braved enemy fire 

over North Vietnam; William Leppert, who survived 

rocket attacks at his base in Danang; Paul Milius, 

who sacrificed his life to save his men in Laos; SEALs 

like Bob Kerrey, who suffered serious wounds to 

gather intelligence; NILOs like Jack Graf, who gave 

his all for the mission; and leaders like Earl Rectanus 

who helped bring success to American arms in the 

vital fight for the Mekong Delta. These men and 

many others in the Navy’s intelligence community 

answered the call in Vietnam when it counted and 

served their country with courage, dedication, and 

professional skill. •

The Authors

Richard A. Mobley retired as a commander in the Navy in 2001 and has since worked as a military intelligence 

analyst for the government. During his career as a naval intelligence officer, he worked closely with many of 

the organizations discussed in this book. He participated in the evacuation of Saigon in 1975 while serving in 

the intelligence center aboard Enterprise (CVAN-65). Subsequent Pacific tours included Chief of the Analysis 

Section in the Fleet Ocean Surveillance Information Facility WESTPAC in Kami Seya, Japan, in the mid-1980s, 

and Chief of Indications and Warning, U.S. Forces, Korea, in the mid-1990s. Mobley has written Flash Point 

North Korea: The Pueblo and EC-121 Crises (Annapolis: Naval Institute Press, 2003) and over a dozen professional articles dealing with intelligence, crisis decision making, and military history in the Middle East and 

Korea. He is a graduate of the National War College, Georgetown University (MA, History), and University of 

California, Davis (BA, Political Science).

Edward J. Marolda has served as the Director of Naval History (Acting) and the Senior Historian of the 

Navy at the Naval Historical Center, renamed the Naval History and Heritage Command (NHHC). He has 

written or edited a number of books on the U.S. Navy’s experience in Southeast Asia, including From Military 

Assistance to Combat, 1959–1965, vol. 2 (with Oscar P. Fitzgerald) in the official series The United States 

Navy and the Vietnam Conflict; By Sea, Air, and Land: An Illustrated History of the U.S. Navy and the War in 

Southeast Asia; and Aircraft Carriers, no. 4 in the Bantam series The Illustrated History of the Vietnam War. 

Dr. Marolda serves as coeditor with Sandra J. Doyle of this series, The U.S. Navy and the Vietnam War, and has 

authored or coauthored a number of its titles. In 2012 NHHC published Marolda’s Ready Seapower: A History 

of the U.S. Seventh Fleet, which covers the fleet’s extensive Vietnam War experience. As an adjunct professor 

at Georgetown University, Dr. Marolda has taught courses on the Cold War in the Far East. He holds degrees 

in history from Pennsylvania Military College (BA), Georgetown University (MA), and George Washington 

University (Ph.D). 

98
Acknowledgments

This book is dedicated to the thousands of U.S. naval personnel who supported naval intelligence collection, 

analysis, and warning—sometimes at great personal risk—throughout the Vietnam War and to their successors 

in today’s naval intelligence community. 

We are especially grateful to Captain Henry J. Hendrix, USN, Director of the Naval History and Heritage 

Command from 2012 to 2014, for his unstinting support of this project. Equally deserving of our thanks are 

Admiral Bruce Demars, USN (Ret.), Vice Admiral Robert P. Dunn, USN (Ret.), and Captain Todd Creekman, 

USN (Ret.), distinguished leaders of the Naval Historical Foundation who enthusiastically endorsed this effort 

to recognize the Navy’s vital contribution to the war effort. This book relied heavily on declassified archival 

material, and we could not have written it without tireless support from John Hodges and John Greco in 

the Operational Archives of the Naval History and Heritage Command. Editors Debra Barker and Andrea 

Connell helped bring this book to fruition. Robert Hanshew, Lisa Crunk, Dave Colamaria, Gale Munro, Pamela 

Overmann, and Karin Haubold at the NHHC and Janis Jorgensen at the U.S. Naval Institute were kind enough 

to help locate the photographs and combat art that populate this book.

Richard Haver, Sidney Wood, Charles Christman, Doug Sherburne, and Bill Leppert graciously provided 

interviews, written comments, and photographs regarding the arcane world of airborne signals intelligence and 

VQ-1’s role in the conflict. Larry Serra, Bill Steshko, Ed Nieuwsma, and John Vinson provided unique insights 

into the varied, dangerous world of Naval Intelligence Liaison Officers while Douglass Hubbard shared from 

his extensive experiences in Naval Investigative Service, Vietnam. Lucian Martinez and Dean Cullison offered 

written inputs about the Naval Advisory Group and Seventh Fleet operations, respectively. 

Our special thanks go to Rear Admiral Tom Brooks, USN (Ret.) and Captain Wood for thoughtfully reviewing 

early drafts of the manuscript. Finally, we are grateful to Cheryl Pellerin, Richard Mobley’s wife and an author 

in her own right, who provided oceans of moral support and thoroughgoing editorial assistance. Despite such 

contributions, we alone remain responsible for the accuracy of this study.

Publisher’s Note

The Naval History and Heritage Command extends a grateful thank you to the Naval Historical Foundation for 

making the U.S. Navy and the Vietnam War series possible. They generously sponsored not only the authors’ 

work on this book, but also the subsequent editorial services that helped make it a reality. The NHHC is grateful for the NHF’s support, and its dedication to telling the story of this important era in the Navy’s history.

99
100

Suggested Reading

Gerhard, William. Southeast Asia in the Shadow of War. Washington, DC: National Security Agency, 1969, 

www.nsa.gov. 

Hanyok, Robert J. “Skunks, Bogies, Silent Hounds, and the Flying Fish: The Gulf of Tonkin 

Mystery, 2-4 August 1964.” Cryptologic Quarterly, http://www.nsa.gov/public_info/_files/gulf_of_tonkin/

articles/rell skunks_bogies.pdf.

Hanyok, Robert J. Spartans in Darkness: American SIGINT and the Indochina War, 1945–1975. Washington, 

DC: National Security Agency, 2007, http://fas.org/irp/nsa/spartans/index.html.

Hubbard, Douglas. Special Agent Vietnam: A Naval Intelligence Memoir. Washington, DC: Potomac Books, 

2006.

Johnson, Thomas R. American Cryptology during the Cold War. Washington, DC: National Security Agency, 

1995. 

Marolda, Edward J. and Oscar P. Fitzgerald. From Military Assistance to Combat, 1959–1965. The United States 

Navy and the Vietnam Conflict vol. 2. Washington, DC: Naval Historical Center, 1986. 

Mersky, Peter. RF-8 Crusader Units over Cuba and Vietnam. Oxford, UK: Osprey, 1999.

Military Institute of Vietnam. The Official History of the People’s Army of Vietnam, 1954–1975. Translated by 

Merle Pribbenow. Manhattan: University of Kansas Press, 2002. 

Moise, Edwin E. Tonkin Gulf and the Escalation of the Vietnam War. Chapel Hill: University of North Carolina, 

1996.

Packard, Wyman. A Century of Naval Intelligence. Washington, DC: Naval Historical Center, 2006.

Powell, Robert R. RA-5C Vigilante Units in Combat. Oxford, UK: Osprey, 2004.

Sherwood, John Darrell. Afterburner: Naval Aviators and the Vietnam War. New York: New York University 

Press, 2004. 

Tillman, Barrett. MiG Master: The Story of the F-8 Crusader. Mount Pleasant, SC: Nautical and Aviation 

Publishing Company of America, 1980. 

DEPARTMENT OF THE NAVY

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