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by Glenn E. Helm
Reference Librarian, Navy Department Library, Naval Historical
Center.
His
research interests include intelligence, surprise attack, and
the history of Indochina. He is currently writing a book on the
intelligence and operational history of the Tet Offensive.
[Originally
published in Pull Together, the Newsletter of the Naval
Historical Foundation and the Naval Historical Center, vol.36,
no.1 (Spring/Summer 1997): 1-5. All rights reserved. No part of
this publication may be reproduced, stored in a retrieval system,
or transmitted in any form, or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without the prior permission
of the author.]
Awaking to the sound of explosions, Rear Admiral
Kenneth K. Veth, Commander U.S. Naval Forces Vietnam (COMNAVFORV),
moved to the rooftop of his rented house to witness a dazzling
display of rockets and flares lighting the Saigon night sky. All
around, the sound of battle during the early hours of 31 January
1968 heralded the arrival of the 1968 Tet Offensive. Armed with
automatic weapons and hand grenades, the Admiral and his housemates
waited for a ground assault which fortunately never came. During
the remaining hours of darkness, Veth kept informed of events
by listening to military police and other tactical communications
on the radio. Since he spent the night on the roof of his house,
he was unable to direct operations from his headquarters.
Despite numerous warnings, the intensity,
coordination and timing of the Tet Offensive surprised the allied
intelligence community, including naval Intelligence. In addition
to a flawed intelligence collection effort, naval Intelligence
and COMNAVFORV misunderstood critical information, resulting in
American naval forces being improperly deployed and surprised
when Saigon and numerous other targets were attacked on 31 January
1968.
During the Tet truce, Task Force (TF) 117
(Riverine Force) was scheduled to deploy into western Dinh Tuong
and eastern Kien Phong provinces, where it was expected to interdict
intensified enemy resupply efforts. Captain Robert S. Salzer,
the commander of the Riverine Force, later called it a "show
and tell" operation, remarking, "there was no reason
whatsoever to be there. We went up there along the skinniest canal
we could, till we ran out of water completely, then we ploughed
through the mud some... Nothing much happened. There was no reason
for anything to happen. The Vietcong were all the way to the east
of us by this time. So much for what [American intelligence] thought
they knew." On the morning of 30 January, the task force
received word that the Tet truce was canceled. Offensive operations
resumed, but infantry units remained near canals for rapid redeployment.
The situation in the Delta deteriorated quickly the next morning
as enemy forces attacked My Tho, Ben Tre, Cai Lay, Cai Be and
Vinh Long. Salzer recalled: "We began to hear rumors that
things weren't going quite so well in our splendid isolation.
Bill Knowlton, who was a brigadier general then flew in, saying
'My God, it's Pearl Harbor over again.'" A Riverine Army
company was airlifted to Vinh Long to support ARVN forces at 1810
on the 31st. Another company was flown to reinforce the defenses
of the permanent Riverine base at Dong Tam, near My Tho. During
the night, the majority of the task force withdrew to Dong Tam,
where they arrived before dawn despite enemy harassment (including
an ineffective ambush). In the fiery glow of nearby fighting,
the Riverine force was resupplied and moved out at daybreak. At
1550 on 1 February, these forces were hurled into battle in My
Tho and, subsequently at Vinh Long and Ben Tre. During the fighting,
as normal sources of intelligence temporarily dried up, the Riverine
Force became heavily dependant on Air Force-supplied radio-direction-finding
fixes for information on enemy unit locations. In the end, the
Riverine Task Force was credited with saving the Delta.
In anticipation of increased enemy infiltration
of supplies from Cambodia, TF 116 (River Patrol Force or Game
Warden), commanded by Captain Paul N. Gray, had deployed nine
PBRs (patrol boats, river) to the Cambodian border region. Four
PBRs were based at the US Army Special Forces camp at Chau Doc
on the upper Bassac River in the northwest of the Mekong Delta.
To the immediate east of Chau Doc, five PBRs were deployed to
the Special Forces camp at Thuong Thoi in Kien Phong Province
to patrol the upper Mekong River. The repositioning of PBRs to
Chau Doc may have had little impact on infiltration, but the vessels
proved crucial in repelling a major ground attack on the city
during Tet. Elsewhere during Tet, TF 116 units engaged enemy forces
at My Tho, Ben Tre, Vinh Long, Sa Dec, the Saigon area and the
LCU (landing craft, utility) ramp at Hue. Remarking on the enemy's
ability to prepare for these attacks without detection, Captain
Gray admitted that "...I have no concrete knowledge of how
such a logistics miracle was accomplished by the VC in the Delta."
The month of January saw increased patrol
activity by Task Force 115 (Coastal Surveillance or Market Time)
as the northeastern monsoon abated. There is no evidence that
TF 115, commanded by Captain R. Dicori, deployed in a different
manner than usual as Tet approached. Even so, a patrol vessel
made what might have been one of the first contacts with enemy
forces at the start of the offensive, when it intercepted five
or six uniformed enemy personnel concealed in an unlighted sampan
three miles south of Qui Nhon, late in the evening of 29 January.
During Tet, Market Time forces became engaged in a number of firefights
involving sampans and provided naval gunfire support to forces
ashore. Harbor defense patrols (Operation Stable Door) engaged
enemy swimmers during the early hours of 31 January but were unable
to prevent damage to the bow of the Norwegian tanker Pelican in
Cam Ranh Bay. Despite extensive commitments in support of allied
forces ashore during the Tet fighting, TF 115 thwarted four enemy
trawlers at the end of February attempting to simultaneously infiltrate
supplies into the RVN.
The Navy's operating forces in Vietnam relied
on COMNAVFORV's intelligence organization, headed by the Assistant
Chief of Staff for Intelligence, Captain Giles C. Upshur, Jr.,
for all necessary intelligence on potential friends, enemies and
operating areas. The organization was also responsible for fulfilling
intelligence requirements of higher headquarters and the Defense
Intelligence Agency. Each commander subordinate to COMNAVFORV
was responsible for maintaining an intelligence collection organization,
and all Navy personnel were expected to report information of
intelligence value. Naval Intelligence personnel were stationed
throughout the RVN, including Coastal Zone and Riverine Area headquarters,
Coastal Surveillance Centers, some PBR bases and some Sector Operations
and Intelligence Centers. An intelligence officer was assigned
to the staff of each of the three Navy task forces. In addition,
an intelligence advisor and a counterintelligence advisor were
assigned to the Vietnamese Navy. Naval Intelligence Liaison Officers
(NILOs), tasked with providing intelligence to COMNAVFORV and
allied naval forces within their assigned geographic areas, were
stationed in 24 towns and cities, primarily provincial capitals
of coastal and Mekong Delta provinces. No boats or watercraft
were assigned to NAVFORV with the primary purpose of obtaining
intelligence.
The task forces played a significant role
in the collection of intelligence. For example, in addition to
questioning and detaining Vietnamese nationals, TF 116 inserted
Provincial Reconnaissance Units and Navy SEAL (Sea, Air and Land)
teams on intelligence collection missions. In support of TF 115,
naval aircraft conducted patrols along the Vietnamese coasts.
The aircraft detected and photographed merchant shipping, observed
patterns of junk movement, and supported surface units during
possible submarine contacts. Relevant intelligence reports and
analysis went to various intelligence consumers. American and
Vietnamese naval intelligence personnel interrogated enemy prisoner
and deserters, exploited documents and materials and produced
intelligence.
James C. Graham, a CIA employee who served
on the Board of National Estimates, recalled, "I think that
there was an intelligence failure at Tet, but I think it was composed
of many elements... the anatomy of any intelligence failure is
always a very complicated thing." Numerous reasons account
for the intelligence failure that led to COMNAVFORV and his intelligence
organization being surprised by the Tet Offensive. The following
list is not exhaustive; it merely provides a basis for understanding
the failure. In some cases, there is strong evidence that a particular
factor contributed to the failure, in other cases the evidence
is less clear but highly suggestive nevertheless.
With a limited staff and a lengthy list of
collection requirements, NAVFORV intelligence personnel could
expend only a small portion of their efforts seeking evidence
of an unprecedented, coordinated, country-wide attack such as
the Tet Offensive. In addition, U.S. Navy operational forces generally
placed a low emphasis on intelligence collection, and it was only
in isolated cases that operational boat skippers were successfully
given intelligence briefs and then meaningfully debriefed after
an operation. TF 115 and TF 116 failed to collect data on ports,
boat identities, routes, cargoes and personnel. Analysis of such
information would have assisted the Vietnamese government to control
water traffic. Rather than utilizing their special warfare skills
for intelligence purposes, operating forces often misused the
SEALS as covert infantry units. Their abilities to conduct infiltration
and reconnaissance, as well as to run agent nets, were often ignored
in the rush to employ them in disrupting and destroying specific
enemy targets.
A major problem faced by NAVFORV intelligence
was the inability of Allied naval patrol forces to significantly
interdict enemy logistic activity along the rivers and coast of
the RVN, with the likely exception of large vessels approaching
from the open sea. As a result, TF 115, TF 116, and Vietnamese
Navy patrols did not obtain evidence of the coming Tet Offensive.
Communist forces, particularly those in the Mekong Delta, utilized
the waterways of the RVN to position personnel and supplies before
the offensive. Yet U.S. Navy coastal and river patrol forces intercepted
and captured virtually none of this water traffic during the several
months prior to Tet. Despite a significant increase in boat and
personnel detention in January 1968, NAVFORV captured a mere 22
weapons, 6.5 tons of rice and no ammunition.
The basic difficulty confronting allied naval
forces attempting to interdict the covert movement of enemy supplies
and forces on or across waterways was that patrol forces were
overstretched and sometimes poorly utilized. A study of the Mekong
Delta completed in the summer of 1967 tallied 732 miles of major
waterways, exclusive of the Rung Sat mangrove swamp. Approximately
90 PBRs were available to cover this area, of which a maximum
of 30 two-boat units were continuously on patrol. They could not
keep all likely areas of enemy activity under constant surveillance.
In practice, PBRs patrolled only those areas of VC activity identified
in regular intelligence reports. An important source of these
reports was aerial surveillance by NILOs who did not have operational
control of aircraft, since they were merely passengers on Army
and Air Force planes. Although NAVFORV had a requirement for daily
surveillance, aircraft were typically available only three days
per week and were not equipped for operations at night, the time
of most enemy activity.
A March 1967 study determined that PBR tactics
(assuming a 10-hour night) included four hours of drifting with
the engine shut down, two hours underway at less than 12 knots,
and 4 hours underway at over 12 knots. PBRs could detect sampans
at 500-1000 yards with radar and other equipment, but only at
100-500 yards without it. However, on a quiet night, one could
hear PBRs operating at high speed more than three miles away.
SEAL teams conducting ambushes along rivers frequently reported
hearing and seeing enemy signals, presumably warning of approaching
PBRs, as much as 30 minutes before their arrival.
COMNAVFORV knew that communist forces used
the waterways in the Third Riverine Area (the south and southwestern
portions of III Corps), including the Nha Be/Saigon, Dong Nai,
Vam Co Tai and Vam Co Dong rivers, for transportation and supply.
Allied security in this area, including the control of river crossing
points, varied enormously. In some places, it was virtually non-existent.
For example, the Bo Bo Canal in Long An Province was particularly
well situated for the transport of supplies from communist base
areas in Cambodia. An intelligence advisor remarked that unless
allied forces gained control of these waterways, "they will
continue to be used at will by the VC/NVA...they will remain basic
routes for infiltration, supply and crossing points for the VC/NVA."
The Senior Intelligence Advisor in the Third Riverine Area during
Tet claimed that Vietnamese naval forces were too slow and that,
"The VC use our rivers at will. To effectively stop them
the Third Riverine needs [US Navy] PBRs, SEALS, and Seawolves
[helicopters]. Without the above the VC will continue to run supplies,
and troops whenever they desire."
The Fourth Coastal Zone, located along the
Cambodian border in the far west of the Mekong Delta, was an area
through which significant amounts of enemy supplies moved from
Cambodia into the RVN. Working together, the NILO at Ha Tien,
American advisors, and the Vietnamese Sub-Sector Chief had developed
an agent network capable of providing early warning of large scale
overland movement of supplies, but they could not obtain rapid
aerial photographic reconnaissance to confirm reports of infiltration.
Moreover, communication with the outside remained uncertain due
to an inadequately performing generator. The nearest aircraft
were located along the coast at Rach Gia, about 50 miles from
the border and even farther from the RVN island of Phu Quoc, located
half-way between mainland RVN and the Cambodian port of Sihanoukville,
through which a great deal of communist supplies were arriving.
Aircraft were only available in the vicinity of Phu Quoc when
not needed on the mainland, and ready reaction to surveillance
needs was considered marginal.
Coastal surveillance resulted in relatively
few interceptions of enemy personnel and material. Although this
was ascribed at the time to the effectiveness of patrols which
discouraged the enemy, it was more likely due to patrolling inefficiencies.
Vietnamese Navy assets similarly were subject to poor utilization,
often being used for base defense rather than aggressive patrolling.
Referring to Coastal Group 12, a Vietnamese Navy unit in I Corps
with responsibility for patrolling lagoons, an American advisor
remarked, "Unfortunately, they perform routine patrols unsatisfactorily
in that the junks are prone to anchor and the crew go to sleep,
day or night." A fellow advisor commented "The attitude
[of] `let the Americans do it' prevailed." In all fairness,
some units conducted creditable patrols, but others were judged
barely satisfactory and some were considered totally unacceptable.
The quality of Vietnamese naval units often
fluctuated over time, due in large measure to the attitude of
their commanding officers. One advisor remarked that emphasis
on numbers of boardings, inspections and detected contacts reduced
the effectiveness of patrols. For example, one naval unit spent
several hours almost daily inspecting a fishing fleet located
3-4 miles off the coast, in the same place on a regular basis.
Enemy units presumably noticed the pattern and slipped along the
coast while the patrol unit was otherwise occupied. American crews
were also affected by pressure to produce results. An advisor
who served in the Mekong Delta observed, "I mean [American
PBR crews will] stop anybody and take in 50 people and call them
suspects if they feel that the pressure is on them to come up
with some suspects."
Another factor was the lack of Vietnamese
language capability among NAVFORV intelligence personnel. Few
Americans managed to master the Vietnamese language before Tet.
In fact, language training for Navy intelligence personnel remained
inadequate until 1970, when the Navy finally devoted greater resources
to the problem. A lack of fluency in Vietnamese meant that Naval
Intelligence personnel were at the mercy of sometimes insincere
or even traitorous Vietnamese personnel. The Intelligence Advisor
to the Vietnamese Navy summed up the need for Vietnamese language
training:
"In my opinion it is not sufficient to rely upon the fact that many Vietnamese officers speak English. Not only are other nationals quite pleased and flattered to find Americans who speak their language, there are important operational requirements as well...it would prevent to a greater extent conversations by Vietnamese "around" the advisor. It is important for Intelligence oriented officers to be fully aware of what is going on around them and to be able to read newspapers and other printed material to be fully effective. The lack of these capabilities detracts from the advisory and intelligence effort."
One Coastal Surveillance Zone advisor remarked
"I don't know if language training would have been of help,
however it might have given me some insight into those I was to
advise."
The failure of Navy personnel to understand
the Vietnamese language was a component of the systemic problem
of the American effort in Indochina, and one linked to the one-year
tour of duty. In the field, less than six CIA officers at a time
together with a small number of military advisors and intelligence
personnel assigned to American units were proficient in the Vietnamese
language.
Poor communication skills and short tours
of duty combined with unfortunate results. One advisor to the
Vietnamese Fleet Patrol felt unable to impress upon his Vietnamese
counterpart the potential that his ship had for collecting intelligence.
Although American liaison personnel could only gather a small
percentage of available information, he considered the Vietnamese
Navy's ability to "read the people" a potentially prime
source of intelligence. He noted that the Vietnamese Navy could
become "more of an intelligence collection agency and less
of an intelligence collation agency if it could only tap the potential
intelligence available through personal contact with millions
of people annually."
Prior to Tet, allied intelligence failed to
recognize changing enemy strategy. Analysts believed the communists
would be foolish to attack urban areas where they would be exposed
to superior allied firepower. The communists would thereby give
up their perceived control over their casualty rate while waiting
for the United States support the Republic of Vietnam to weaken.
Other issues commonly associated with the
Tet intelligence debacle such as enemy deception, enemy indecision,
false alerts, analysts' fear of crying wolf, poor information
sharing, and information processing difficulties also contributed
to the failure to provide warning of the upcoming offensive.
Of particular importance to the issue of whether
the Navy had sufficient warning of Tet was all- source intelligence
available to Admiral Veth and his intelligence organization on
27 January. This information painted a dramatic picture of enemy
activity and indicated that a major enemy offensive was imminent.
It should have produced a maximum state of American vigilance
as Tet approached. Widespread communist attacks in the northern
portion of the Republic of Vietnam during the night of 29/30 January
could have provided 24 hours warning, yet NAVFORV was still unprepared.
COMNAVFORV and his intelligence organization
were surprised by the intensity, coordination and timing of the
Tet Offensive, as evidenced by Admiral Veth's presence at his
residence during the first wave of attacks on Saigon. Of the many
factors that led to the intelligence community's surprise at the
offensive, the misguided belief that enemy forces would not run
the risk of attacking the cities and towns of the RVN is paramount.
The belief that an attack during the most important Vietnamese
holiday was an almost unthinkable enemy option was similarly misguided.
Had the allied intelligence community placed greater emphasis
on intelligence collection, and acted properly on the intelligence
that they did receive, the Tet Offensive may never have found
its way into the history books as one of the greatest intelligence
lapses in the post-World War II era.
For further reading on intelligence and the Tet Offensive:
Ford, Ronnie E. Tet 1968: Understanding the Surprise. London:
Frank Cass, 1995.
Helm, Glenn E. The Tet 1968 Offensive: A Failure of Allied
Intelligence. MA thesis. Tempe AZ: Arizona State University,
1989.
Hoang Ngoc Lung. The General Offensives of 1968-69. Washington:
US Army Center of Military History, 1976.
Oberdorfer, Don. Tet. Garden City NY: Doubleday, 1971.
Wirtz, James J. The Tet Offensive: Intelligence Failure in
War. Ithaca NY: Cornell University Press, 1991.
3 August 1998