Coastal Raiders


Author: Trần Ðỗ Cẩm (
English translation: Donald C. Brewster, May 2000
Internet edition: Phạm Cường Lễ, May 2004

Classified Information Disclosed for the First Time
The Navy of the Republic of Vietnam Was Active in the Gulf of Tonkin
English translation by Donald C. Brewster, May, 2000
Internet edition by Phạm Cường Lễ, May 2004

Before learning more about the organization and activities of the Coastal Security Service, it will be necessary to clarify a few things in an effort to avoid any misunderstanding. This article is based in large part upon those things that I (the author) know and remember from the five continuous years during which I served as an Executive Officer and then a Commanding Officer of a PT Boat in the Sea Patrol Force of the RVN. I participated in more than one hundred missions of every type in the territorial waters of North Vietnam from 1965 to 1970. I learned of a number of major incidents which occurred around this period from the reports of others and gathered some information through recent interviews with those who took part in the missions.

Therefore, while every attempt is being made to be objective, time always affects memory to some degree so that errors are not always avoidable. However, it is hoped that well-informed sources, especially the original participants, would happily contribute their thoughts and fill in the blanks so that the veracity of the naval history of the Sea Patrol Force would be ensured. We also wish to clarify that our desire is to present the truth without censure or criticism of anyone, especially those Vietnamese and American srohtua whom we esteem and admire. They have worked hard to research and collect material on the subject of the Sea Patrol Force and Coastal Security Service of the RVN. To them we give our heartfelt thanks.

Trần Ðỗ Cẩm
Dedicated to the Comrades in Arms of the Coastal Security Service

The author reserves all publication rights.
Please contact Trần Ðỗ Cẩm at:


The war in Vietnam between the Nationalists and the Communists took different forms as both sides tried many different ways to gain an advantage and eliminate the enemy from the battlefield. The print media and numerous films have meticulously analyzed and clearly reiterated the famous clashes such as the Tết Offensive and the incursions into Laos as well as the battles at Quảng Trị, Kontum and An Lộc, etc., in which the combatants of both sides invariably totaled many army divisions. Of course, just below the surface of the conventional war which everyone knew all too well, there was a hidden aspect of which few were aware.CoastalRaiders-009

When we speak of what were known then as covert operations we must remember that even those who were engaged in them knew only their duties or the part they played. Beyond being aware of the designation, Special Forces, those who were not directly involved did not have a clear view of what was happening. In general, Special Forces included many of the various military services that made up the Armed Forces of the Republic of Vietnam (ARVN), which sometimes even included civilian personnel. Their duties included raids into enemy territory or behind enemy lines to gather intelligence and attack enemy targets. They also carried out many missions to detain individuals for questioning and engaged in psychological warfare operations among the enemy population.

Because these activities were very dangerous and carried out under cover of darkness, the great majority of the Special Forces rank and file were volunteers. We all have heard of the famous flying teams known to the Vietnamese as the Thunder Tigers (Lôi Hổ) or Black Dragons (Hắc Long) and Squadron 219 (Phi Ðoàn 219) of the Air Force. Equally well known are the Delta Force and Rangers, etc., who were part of the infantry. In regards to the Navy however, except for the SEALS, all other units remain shrouded in secrecy to this very day.

In every special operation conducted behind enemy lines, especially those that included cross-border missions into North Vietnam, Laos or Cambodia, the participants were usually divided into two groups: the operations team which was usually nicknamed “the team” (“toán”) had the duty of actually going ashore to carry out the mission they had been given and the support team, which had the responsibility for providing the transport that would drop off and retrieve the operations team as well as provide fire support when required.

Infantry teams did not have an inherent transport or fire support capability by either air or sea and therefore could only undertake duties that fell into the category of the former. By contrast, the Air Force, which did not have its own operations team, could only participate by providing transport and support. As for the Navy, it was unique in that it could undertake both special and support operations because in its makeup was an inherent capability to perform both tasks mentioned above.

The special operations that were carried out by the various teams such as the Thunder Tigers, Black Dragons, Squadron 219 and the Delta Force took place within the territory of the RVN, Laos or Cambodia while the later incursions into North Vietnam were undertaken almost exclusively by the existing units of the RVN Navy. The operational elements of the Navy were the SEALS and a transportation/support unit which was known as the Sea Patrol Force.

In an operational sense Sea Patrol Force was considered a unique unit of the Special Forces that could undertake special missions inside North Vietnam. Those missions included shelling targets on shore, capturing and detaining fishermen to develop intelligence and distributing pamphlets, etc., all without the assistance of any other force. Both the SEALS and the Sea Patrol Force operated under the authority of the Coastal Security Service.

In that the Coastal Security Service was always an integral part of the Special Forces, we should scrutinize its personnel and organization so that the task of understanding this service will become clearer and easier.


Right after the Geneva Peace Agreement that divided Vietnam into North and South was signed in 1954, Mr. Allen Dulles, Director of the Central Intelligence Agency (CIA), assigned Air Force Colonel Edward Lansdale to South Vietnam to assist Premier Ngô Ðình Diệm in consolidating his position in the South and organizing paramilitary units that had been left in place in North Vietnam before the Communists came to power. Colonel Lansdale assumed the post of Deputy Director of the Office of Special Operations that was directed at that time by Brigadier General Graves Erskine. His mandate was to take charge of secret counterinsurgency operations in Vietnam as he had done for Philippine President Magasasay who was successful in exterminating the rebel forces of the Huk Communists during the 1950’s. Colonel Lansdale’s organization in Vietnam was called the Saigon Military Mission (Phái Bộ Quân Sự Saigon) and it included Infantry Major Lucien Conein, a professional spy who would play a very important role in the political upheavals that characterized the First Republic in South Vietnam (Ðệ Nhất Cộng Hòa).

Just before the North was handed over to the Communists many Vietnamese civilians were recruited by Colonel Lansdale. Most of them came from the Vietnamese ethnic minority known as the Nùng and some were native to Móng Cái, which is situated near Hải Phòng. Others came from areas near the Chinese-Vietnam border, however, they were all sent to Saipan for training in the basics of counterinsurgency.

By the time Vietnam had been officially divided in two, the Nùng had been well trained and assigned to small teams. Subsequently, the warships of the U.S. Seventh Fleet put troops ashore near the areas that the Nùng recruits called home and ordered them to infiltrate and remain inactive in place until they received further orders. Weapons, radios and gold were prepositioned in secret locations to be retrieved when needed. One of the undercover spies at this time was a man named Phạm Xuân Ẩn but Colonel Lansdale was not aware that he was an agent of the Vietnamese Communists who had infiltrated our organization.

After the situation in South Vietnam had become relatively stable, President Ngô Ðình Diệm organized a special intelligence unit to operate exclusively under his control at the Palace. It was directed by Dr. Trần Kim Tuyến, a native of Huế in Central Vietnam. One of the units under the authority of Dr. Tuyến that included guerrilla activity was the Liaison Office (Sở Liên Lạc) which was run by Colonel Lê Quang Tung and his Deputy, Colonel Trần Khắc Kinh. Captain Lê Quang Triệu, the younger brother of Colonel Lê Quang Tung, was responsible for recruitment at the Liaison Office and was also the Company Commander for the intra-service company known informally as the Palace Guard (Ðại Ðội Liên Binh Phòng Vệ Phủ Tổng Thống). In addition, Presidential Adviser Ngô Ðình Cẩn also had his own intelligence organizations in Central Vietnam.

The Liaison Office was divided into three parts known as the Northern Operations Service (Sở Bắc), the Southern Operations Service (Sở Nam) and the First Observation Group (Liên Ðội Quan Sát).

Northern Operations Service. This service was also called Office 45 (Phòng 45) under the command of Infantry Captain Ngô Thế Linh. Although called the Northern Operations Service, this group also undertook covert operations in Laos and Cambodia. Generally speaking the Northern Operations Service shouldered the responsibility for guerrilla activities that took place outside the territory of the RVN.

Southern Operations Service. The southern service was also known as Office 55 (Phòng 55) and was under the command of Infantry Captain Trần Văn Minh. It was responsible for guerilla operations within the territory of the RVN.

The First Observation Group. In addition to the Southern and Northern Operations Service, the Liaison Office also had a special structure of which only a few people were aware. It was called the First Observation Group and was established in 1956 with the assistance of the U.S. Pentagon and the CIA.

Outwardly, the group was only a regular outfit with a number of administrative personnel but in reality all of its activities were under the disposition of the Liaison Office. The Personnel of this group received special training to infiltrate and lay low in the South in the event the RVN fell into Communist hands after the general elections that were called for in the Geneva Accords. These operational teams of the group remained in place until 1958 and even though the elections were canceled, the teams still buried weapons and explosives as well as radios and gold, etc., in preparation for underground operations when and if they became necessary.


In 1958 when the situation in the South had become relatively stable, President Ngô Ðình Diệm officially requested that the U.S. provide assistance in carrying out guerrilla operations in North Vietnam. Therefore, when Mr. William Colby of the CIA was assigned to Saigon on January 1, 1959 to make whatever arrangements were required, the coordination of guerrilla activities between the U.S. and the RVN officially started. In general, operations to infiltrate North Vietnam were carried out by air and by sea.

1. Infiltration by Air

As for the use of air, in the beginning the CIA hired a number of pilots from the China Air Lines Company in Taipei in order to train Vietnamese pilots. Later, the Transport Squadron of the RVN Air Force led by Lieutenant Colonel Nguyễn Cao Kỳ, undertook flights that dropped special force paratroopers in the North.CoastalRaiders-010

The first flight occurred on May27, 1961 when Lieutenant Colonel Nguyễn Cao Kỳ himself flew as the lead pilot in a C-47 aircraft. Four members of the team known as Caster were dropped into a mountainous jungle area of Sơn La, a province not too far from the Chinese border. They were all Nùng ethnic minorities who had originated in Sơn La and were now serving with the 22nd Infantry Division, a unit that consisted mostly of ethnic minorities from the North who had come South. The Caster team was led by Hà Văn Chấp and had been placed under the authority of the Topography Exploitation Service of Office 45 (Sở Khai Thác Ðịa Hình thuộc Phòng 45) also known as the Northern Operations Service. After completing the mission the aircraft piloted by Lieutenant Colonel Kỳ returned safely through the airspace over Laos.

2. Infiltration by Sea

The infiltration of North Vietnam by sea began very early, only a few years after the country was divided in two. Various incursions began in1956 when the Liaison Office needed a number of wooden junks in order to step up the placement of personnel and resupply by sea those teams that were already in place in North Vietnam.

In the beginning there were only six civilians, all of whom were natives of Quảng Bình Province and had earlier evacuated to the South. They were recruited in the city of Nha Trang to enter the new ocean going force that had just been established. This early operation into the territorial waters of North Vietnam consisted of a number of short incursions, each of which lasted for only a few days and was accomplished in small junks that looked like all the other fishing junks in the area and thus easily used them as cover. Later as the need for operations increased more personnel were recruited and a number of larger junks were outfitted to accomplish the task at hand. The force that included all of these civilian personnel was a part of the Northern Operations Service which remained under the command of Infantry Captain Ngo Thế Linh. Captain Ngô Thế Linh was known affectionately to all of us as “Mr. Bình” and was generally viewed by all those who came after as the founding father of the Coastal Security Service and the Sea Patrol Force of the RVN.

While support and liaison missions by sea continued, it was not until February, 1961 that the secret service of Dr. Trần Kim Tuyến, with the help of the American CIA, actually put two spies ashore in Quảng Yên. Both of these individuals, one who hailed from the RVN and the other, a northerner named Phạm Chuyên, landed safely. Phạm Chuyên had been a mid-level Communist cadre who rallied to the RVN through its Returnee Program by coming south across the 17th Parallel in 1959. His alias was Ares and proof later surfaced indicating that he was a double agent.

3. Nautilus Fishing Junks

Following the placement ashore of the two agents mentioned above, the junks used in the infiltration of the territorial waters of North Vietnam were given the nickname of Nautilus after the name of Captain Nemo’s mysterious submarine found in Jules Verne’s science fiction classic, 20,000 Leagues Under the Sea. The missions were also known as Nautilus and during this period infiltration of North Vietnam by sea proceeded relatively easily.

Up until this time the Nautilus operations were all conducted by the CIA. The Nautilus crews were civilians that had been recruited by the CIA but there were also a number of RVN Navy frogmen that had received special training to carry out sapper attacks using explosives. Most of these frogmen were in a team of 18 sailors that had received special training in Taiwan in August, 1960.


In the beginning a number of Nautilus missions to infiltrate by sea produced good results because the enemy had not yet been able to mount a defense or otherwise react to them. But as time went on, the missions were less effective because the enemy increased his shore patrol forces and many of the missions by junk were disclosed in advance by improved enemy intelligence.

The use of junks had only one advantage and that was that they could hide among the local fishing vessels. However, as intelligence was developed by the enemy from the crews of the fishing junks whom we had detained, it appeared that the enemy knew very well the routes that were used for infiltration and it became difficult to avoid contact during the missions. Moreover, the Nautilus junks all had very slow speeds and weak firepower that kept them from protecting themselves when discovered and pursued.

For these reasons, Admiral Harry G. Felt, U.S. Commander in Chief, Pacific, decided that the secret organizations of the CIA did not have sufficient capability to complete their infiltration missions. He proposed that assets of the U.S. Navy be used and suggested replacing the Nautilus junks with U.S. submarines.CoastalRaiders-003

To find a solution to this problem Defense Secretary Robert McNamara convened a meeting in or around July, 1962 that included the Defense Department, Department of State and the CIA. Everyone in attendance agreed to transfer responsibility for the commando attacks on North Vietnam from the CIA to the Department of Defense. The transfer itself was dubbed Operation Switchback and was to be completed within one year. In December, 1962, the National Security Council Special Working Group agreed with Admiral Felt’s earlier recommendation to use PT Boats and frogmen to carry out the infiltration missions into North Vietnam. Of course at that time neither the vessels nor the personnel had yet arrived on site.

Operation Switchback formally began on January 1, 1963. From then on, the Military Assistance Command, Vietnam (MACV) assumed the responsibility for operations along the border that were being directed at that time by CIA Officer Gilbert Layton. Layton remained as Colonel George Morton’s deputy when he replaced Layton and set up Team C of the Special Forces with its headquarters in the city of Nha Trang. As for the activities in North Vietnam, even though they were under the authority of MACV, CIA Officer W. T. Cheney remained in charge. By April, 1963, a Special Forces Training Center had been set up in Long Thành to train the teams that would be dropped in North Vietnam. Meanwhile, the CIA made preparations to turn over the infiltration missions into North Vietnam to the military authorities.


In May, 1963, the U.S. Joint Chiefs of Staff ordered Admiral Harry G. Felt to prepare a plan to support the RVN’s effort to carry out special operations in North Vietnam. In June, 1963, Admiral Felt and the Joint Chiefs outlined a preliminary operational plan, the strategy of which was to use hit and run attacks against the North Vietnamese in order to compel them to reduce their military efforts against the RVN. According to this plan, ARVN would provide the personnel and the U.S. would supply the transportation and training. The plan was known as OPLAN 34-63 and was accepted by the Joint Chiefs of Staff on August 14th with the request that a few small details be changed. Adjustments were made to the plan and it was approved once again on September 9, 1963.

In the Conference on Vietnam that was held in Honolulu on October 20th, William Colby, who had been reassigned from his post in Vietnam to CIA Headquarters in Washington, D.C. to serve as CIA Director for all of the Far East, indicated to the Secretary of Defense that based on the experience of the CIA, dropping small teams into North Vietnam would be unsuccessful. However, high placed U.S. officials disagreed arguing that the CIA had failed because it lacked the means and the capability. Therefore, the CIA was ordered to turn over the plan to infiltrate North Vietnam to the Army.

While preparation for the plan was proceeding nicely, an unexpected development occurred that had major consequences for the project. That was the Coup d’etat against President Ngô Ðình Diệm that took place on November 3, 1963. It caused considerable confusion for the Government of Vietnam and affected the implementation of its operational plans. The two people who led President Diem’s secret service, Dr. Trần Kim Tuyến and Colonel Lê Quang Tung no longer existed. Brigadier General Lê Van Nghiêm was assigned to the post of Special Forces Commander and was replaced only a few months later by Colonel Pham Ðình Thứ. However, Office 45 or the Northern Operations Service and Office 55 or the Southern Operations Service still remained under the direction of Ngô Thế Linh and Trần Văn Minh.

Even though there were obstacles the guerilla attacks by sea continued. Within the parameters of OPLAN 34-63 and during November, 1963, a number of frogmen who made up the operational teams left Ðà Nẵng for training at the Cửa Việt Naval Base where they would prepare for a sapper mission to destroy ships in the harbors of North Vietnam just north of the 17th Parallel. One mission which was planned for December, 1963, was aimed at North Vietnamese patrol craft at the Quảng Khê Naval Base which was situated at the mouth of the Giang River in Quảng B7nh Province and was also the location of the Southern Sector Headquarters of North Vietnam’s Navy. Before the mission began the American advisers provided aerial reconnaissance photos of the base at Quảng Khê. While underway the mission was scrubbed due in part to inclement weather. One of the frogmen who participated in the raid was Vũ Văn Gương.

While progress was achieved in training, guerrilla operations did not produce the desired results by the end of 1963. The reason was that the organization lacked structure and most of the civilian personnel did not have the technical training or the discipline of the military. Therefore, the direct participation of ARVN was needed.

Both the CIA and MACV ordered adjustments to OPLAN 34-63 and after a time a new plan known as OPLAN 34 A became the centerpiece for infiltrating North Vietnam by sea. The new plan, dubbed Operation Tiger by the CIA was presented to the U.S. Joint Chiefs of Staff on December 15, 1963.CoastalRaiders-004

A few days before on December 12th, Defense Secretary McNamara advised Ambassador Henry Cabot Lodge that President Johnson wanted to emphasize the special operations aimed at North Vietnam and also wanted ARVN with U.S. support, to assume responsibility for them. These operations were designed to subtly inform North Vietnam that the U.S. would not accept the Communist invasion of the RVN and if North Vietnam stubbornly persisted in the use of force, it would be defeated.

To summarize, the principal objective of OPLAN 34A was to combine the attacks against North Vietnam with military and diplomatic pressure to serve as a warning to North Vietnam to not increase its activities in Laos and in the RVN. Thus, from a plan that was implemented by the CIA with the objective of gathering intelligence and wreaking havoc on the North, OPLAN 34A had now become an operation that was heavily weighted on the political aspects of the confrontation.

Also on December 15, 1963, in response to high level directives, the U.S. Navy set up a Mobile Support Team (Toán Yểm Trợ Lưu Ðộng) in Ðà Nẵng. This team consisted of a number of U.S. Navy frogmen known as SEALS, U.S. Marine Intelligence Officers and many American specialists experienced in guerrilla operations. Additionally, two PT Boat crews had recently arrived in Ðà Nẵng. The purpose of the Mobile Support Teams was to train Vietnamese crews in how to operate the PT Boats and use them in commando raids by sea. The U.S. would provide maintenance and support services.

On December 19th, the U.S. Army Command in the Pacific asked the Joint Chiefs of Staff for permission to implement OPLAN 34A on an experimental basis for a period of 12 months.


It is worth noting that OPLAN 34A called for the participation of ARVN but since the RVN was not involved in planning for the project, it was not able to make timely preparations. It was on January 21, 1964 that the U.S. Joint Chiefs of Staff agreed to implement the first phase of OPLAN 34A. It was not until that time that Ambassador Henry Cabot Lodge advised the RVN Chief of State Dương Văn Minh about the plan and requested that the RVN cooperate by supplying ARVN manpower.

On January 24th, the Special Operations Group was formed with Colonel Clyde Russell as its commander and since it operated under the authority of MACV, this special group became known as MACVSOG or MACSOG. Later in 1964 the Special Operations Group was renamed the Studies and Observation Group (Toán Nghiên Cứu và Quan Sát) to give it a more civilian sounding title but it was still called by the acronym MACSOG.

Speaking generally, OPLAN 34A had four main responsibilities: to insert teams by airdrop, provide logistic support by air, conduct operations on the sea routes and engage in psychological warfare. Of all these projects, the “air team” had the most personnel as the CIA left behind 169 Vietnamese who were still in training at Long Thành, the majority of them civilians.

On January 28, 1964, General Nguyễn Khánh’s takeover of the GVN, or as he called it “reform,” slowed down the progress of MACSOG as the U.S. needed the acceptance and cooperation of the new government. General Khánh was a proponent of striking against the North so the Strategic Technical Service (Sỡ Kỹ Thuật) was set up on February 12th under the direction of Colonel Trần Văn Hổ at the RVN Ministry of Defense. Its mandate was to work along with MACSOG. This service was actually the reincarnation of the Topographic Exploitation Service (Sở Khai Thác Ðịa Hình) which had formerly been directed by Colonel Lê Quang Tung during the time of the First Republic. Its name was later changed to the Strategic Technical Directorate (STD, or Nha Kỹ Thuật).


As for the command function, Washington maintained total control and was responsible for all operational planning. MACSOG and the Technical Service in Vietnam shouldered the responsibility for carrying out the operations. MACSOG and the Technical Service had almost no voice or any influence when it came to proposing, approving or arranging the schedule for the operations.

As for organization, the American side maintained a group under MACSOG which was known variously as the Naval Advisory Detachment (NAD) or the Maritime Operation Group (MAROPS) that specialized in running the coastal commando operations that had the responsibility for putting guerrillas ashore and carrying out sapper attacks against enemy vessels. In addition to these military operations they also implemented exploratory/survey operations along the coast of North Vietnam.

On the Vietnamese side, the Technical Service and the Coastal Security Service both worked right alongside the Naval Advisory Detachment. These two organizations were often called NAD/Coastal Security Service and they were headquartered together to facilitate coordination at a place in Ðà Nẵng known as the White Elephant. Those in command at Coastal Security Service coordinated closely with the Naval Advisory Detachment concerning the disposition of personnel and the briefings and after action reports for each mission, etc. Coastal Security Service also worked very closely with the Mobile Support Teams.

When the coastal infiltration teams operated under the direct authority of the CIA in the past there were a number of RVN Navy frogmen involved but the majority of Nautilus personnel were civilians. But, when Operation Switchback turned the command and control of the special operations from the CIA to the U.S. military, the Nautilus junks were slowly replaced by more modern PT Boats. The Sea Patrol Force was also established to include officers and crew members from the RVN Navy who were especially chosen for this duty. The Sea Patrol Force was placed under the operational authority of the Coastal Security Service which was under the jurisdiction of the Technical Service.

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