Riverine Operations
1966-1969
III Corps Operations and the Threat to Dong Tam
On 11 and 12 June 1967 the fully constituted Mobile Riverine Force made its first major move. Leaving Dong Tam, it sailed down the Mekong River and across a stretch of the South China Sea to a temporary anchorage at Vung Tau, and thence to an anchorage southeast of Saigon at Nha Be-a total distance of sixty miles. At Vung Tau it received additional Navy assault craft that had arrived from the United States. Since the assault support patrol boats that had been scheduled to join the force at this time were delayed, armored troop carriers continued to perform minesweeping and security operations until arrival of the assault support patrol boats in September and October. Upon reaching the Nha Be anchorage, the force returned to the Vietnamese Navy the borrowed craft it had used since February. With the new assault craft, the flotilla had 52 armored troop carriers, 10 monitors, 4 command boats, and 2 refuelers.
From the Nha Be anchorage operations were conducted from 13 through 17 June in the Rung Sat Special Zone as part of the U.S. 9th Division operation, GREAT BEND, which brought greater security to the Long Tau shipping channel. Although the force found a base camp believed to have been the recent site of the headquarters controlling Viet Cong actions in the Rung Sat Special Zone, no contact was established with the enemy.
On 18 June the Mobile Riverine Force moved eight miles to a mobile riverine base anchorage at the junction of the Soi Rap and Vain Co Rivers in preparation for operations in the Can Giuoc District of eastern Long An Province. One battery of supporting 155-mm. self-propelled artillery was moved by LCU to the west bank of the Soi Rap River adjacent to the mobile riverine base at the confluence of the Soi Rap and Vam Co Rivers. Ammunition supply for the battery was transported from Vung Tau by Army LCM-8's while the barge-mounted artillery continued to receive ammunition support from the LST supply ship in the base.
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Before entering Long An Province, the brigade commander briefed the battalion and company commanders on their new area of operations. The battalions of the 2d Brigade had fought in Dinh Tuong and northern Kien Hoa Provinces where trees lined the banks of most streams and major canals. Although the soldiers were familiar with moving in the rice paddies near Dong Tam, they had seldom encountered such wide expanses of open paddy as existed in eastern Long An Province. These open areas provided observation and fields of fire that dictated greater dispersion of men and greater reliance on the "scouts out" technique. A long proven infantry tactic in open terrain, scouts out provided for point and flank security men to move out on foot as much as 500 meters from the remainder of their squad to provide early warning.
In further preparation for entering eastern Long An
Province the brigade commander, S-2, and S-3 visited the 3d Brigade, 9th
Infantry Division, and the 2d Battalion, 3d Infantry, 199th Infantry Brigade
(Separate) . Both of these units had operated in Long An and furnished helpful
information. The group also visited the headquarters of the 46th Regiment, 25th
Division, Army of Vietnam, and the Can Giuoc District headquarters. Although
such visits risked exposing planned operations to compromise, the risk was
accepted in order to exploit local intelligence and take advantage of operating
in conjunction with other U.S. and Vietnamese units. For the Can Giuoc
activities, the Mobile Intelligence Civil Affairs Team set up operations with
the 2d Battalion, 46th Regiment, Army of Vietnam, and Can Giuoc District
headquarters on 19 June, the first day of Mobile Riverine Force operations in
Long An.
Can Giuoc District contained a good network of navigable waterways, permitting the assault craft to enter an area that intelligence reports indicated was used extensively by Viet Cong regional forces for rest and training. Civilian travel in the locality was chiefly by water, since most bridges and the one ferry were no longer serviceable. Previous military actions here had depended for movement on boats and aircraft. The U.S. 9th Infantry Division's 3d Brigade was disposed in Long An Province west of Can Giuoc District to lend security by its operations to Highway 4; however, Can Giuoc District was outside the brigade's routine area of operations.
The fact that the Mobile Riverine Force could move its afloat base permitted the establishment of a brigade base within three
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kilometers of a location that had been a remote Viet Cong base area enjoying considerable security. To attack this area, Colonel Fulton and Captain Wells had agreed to anchor the riverine ships as close as practicable to the area of operations. The time needed by assault craft to enter the area and the turnaround time of both helicopters and water craft conducting resupply and medical evacuation would thus be reduced. The base was moved into its anchorage on the evening before operations. The risk of disclosing the intended area of operations by this move was accepted because the
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force had not been in the area before and the Viet Cong were not thought to be familiar with the capabilities of the ships and assault craft. The brigade and flotilla commanders agreed that assault craft would go up only those streams wide enough to permit them to make 180-degree turns. Colonel Fulton and Captain Wells also agreed to use a portion of the assault craft as a blocking force once Army troops had landed. The boats were to enter the waterways as the tide was rising, permitting greater speed and a long period of high tide level immediately following entry.
The Mobile Riverine Force sent five companies of the two U.S. infantry battalions into the operations area by assault craft. (Map 6) The sixth company, Company C, 3d Battalion, 47th Infantry, moved by water to an air pickup zone to stand by as reserve. The troops entered the area and searched south, using assault craft to cross water barriers and to provide communications and fire support. The 2d Battalion, 46th Infantry, Army of Vietnam, moved during darkness and established a blocking position near the town of Ap Bac, oriented to the east.
At approximately 1000 Colonel Fulton was notified through the Mobile Intelligence Civil Affairs Team, located near Can Giuoc District headquarters, that the district chief had information of a Viet Cong battalion-size force due east of the blocking position of the 2d Battalion, 46th Infantry. The brigade commander issued a fragmentary order at 1010 informing the commanders of the 3d and 4th Battalions, 47th Infantry, and the U.S. adviser to the Vietnam Army battalion of the reported enemy strength and location. The order directed the two U.S. battalions to continue their maneuver south toward the newly designated objective-the reported location of the enemy battalion. Colonel Fulton also directed Colonel Tutwiler, commanding the 4th Battalion, 47th Infantry, to prepare to assume control of Company C, 3d Battalion, 47th Infantry, and to deploy the company by helicopter south of the reported enemy location.
Colonel Tutwiler moved Company C at 1105 by air south of the reported enemy location with the mission of moving northeast to reconnoiter the enemy position. He sent Company C of his battalion by assault craft south on the stream and landed the company at 1135 northeast of the reported enemy position.
By 1150 Company C of the 3d Battalion had swept the reported enemy location without finding the Viet Cong. Company C of the 4th Battalion was moving west from its landing area when it was fired upon from the north. At the same time Company A of the 4th
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Battalion, moving south but at a distance of some 800 meters north of Company C, 4th Battalion, encountered heavy automatic weapons and small arms fire from its front and right flank. The enemy position had turned out to be north of the reported location. Company A, lacking cover, suffered heavy casualties. The Viet Cong had occupied well-fortified firing positions in an L-shape along the north bank of the stream that separated Company A from both Company C of the 3d Battalion and Company C of the 4th Battalion, 47th Infantry.
Colonel Tutwiler shifted Company B of his battalion, which had been moving on the battalion right flank, into the area behind Company A to assist by fire and with medical evacuation. He held his Company C on the south side of the stream to maintain contact and maneuvered Company C, 3d Battalion, north across the stream. Once on the north bank, Company C, 3d Battalion, fought slowly to the east, with its right flank on the stream. Major H. Glenn Penny, executive officer and acting commander of the 3d Battalion, 47th Infantry, meanwhile moved his Companies A and B southeast to link up with Company C of the 3d Battalion on that company's north flank. At 1545 Major Penny resumed operational control of his Company C. Company B attacked east on line with Company C while Company A moved into a blocking position 600 meters north of the left flank of Company B. By 2000 darkness and enemy fire prompted a halt to maneuvers and placed Companies B and C, 3d Battalion, some 600 meters west of Company C of the 4th Battalion where the units remained throughout the night of 19-20 June.
In the movement of the two U.S. battalions toward the first reported enemy location, the naval assault craft were limited to movement on the stream paralleling the 4th Battalion's left flank. When Company C of the 4th Battalion was fired upon at 1150, the naval assault craft that had brought in the company provided fire support for it and, later, for Company C of the 3d Battalion as it crossed the stream west of the actual enemy positions.
Although the rifle companies and the naval assault craft quickly returned the enemy fire, artillery and helicopter gunship fire could not be immediately brought to bear because the heavy casualties initially suffered by Company A of the 4th Battalion prevented the company commander from determining the dispositions of his platoons. Artillery fire began at approximately 1200; it was delivered at the request of the forward observers and coordinated by both ground and airborne artillery observers. Support was provided
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during the daylight hours and well into the night by helicopter gunships, medical evacuation helicopters, and assault craft.
The movement of Companies A, 13, and C, 3d Battalion, 47th Infantry, required the entire afternoon, but not all companies were able to link up before dark. The 2d Battalion, 46th Vietnam Army Infantry, remained in its original position during the engagement because Colonel Fulton decided that maneuver of the battalion to the east would be complicated by the presence of U.S. companies between the Vietnam battalion and the enemy.
Viet Cong and U.S. troops exchanged fire throughout the daylight hours and into the night. U.S. troops found that the enemy's reinforced bunkers could be destroyed only by 90-mm. recoilless rifle fire and helicopter rockets and bombs; the 20-mm. and 80-mm. rounds fired by the assault craft penetrated a bunker only after multiple hits.
Casualties of Company C of the 3d Battalion were evacuated during the afternoon and evening of the battle by plastic assault boat and helicopter. Company C of the 4th Battalion was unable to use the assault craft for medical evacuation and relied on helicopters. Whether casualties were taken directly by helicopter from a ground pickup zone or from an armored troop carrier aid station after treatment, they were sent either to the barracks ship USS Colleton or to a field hospital.
During the afternoon and evening of 19 June most of the enemy losses came from U.S. supporting fire concentrated on a small area. A portion of the enemy battalion eluded the U.S. blocking positions during the night, probably by crossing the stream to the west of Company C, 4th Battalion, 47th Infantry, and then moving south. On 20 June the 4th Battalion, 47th Infantry, searched south to region contact with the enemy. Moving by helicopter and on foot the battalion found the enemy north of the Rach Gion Ong stream at Ap Nam and, aided by a company of the 2d Battalion, Goth Infantry, encircled and eliminated an enemy platoon. The company from the 2d Battalion, 60th Infantry, vas provided from the 3d Brigade by the Commanding General, 9th Infantry Division.
Following the battles of 19-20 ,June, the Mobile Riverine Force remained in the Can Giuoc area, capitalizing on the knowledge obtained of the area and attacking small elements of the Viet Cong 5th Nlia Be Battalion and local guerrillas with whom battle had been joined on 19 June. On 23 ,June Company A, 4th Battalion, 47th Infantry, which had taken heavy losses, was moved by air to Dong Tam to begin a two-week period of refitting and retraining. Operations were conducted in the Rung Sat Special Zone, the Can
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Duoc District of Long An Province, and Go Cong Province of IV Corps. Companies on independent missions entered the smaller waterways by ATC at night to establish widely dispersed ambushes. Infantry platoons set up ambushes ashore in co-ordination with ATC's and monitors to interdict land and water routes. Cooperating with the 199th Infantry Brigade (Separate) and the 2d
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and 3d Battalions of the 46th Vietnam Anny Infantry Regiment, the force ranged in widely dispersed formations to find the enemy. An assault helicopter company provided by II Field Force was used extensively to trove troops when the riverine assault craft were limited by the lack of navigable streams or by their relatively slow movement.
On 4 July the Mobile Riverine Force again co-operated with Vietnamese forces to attack an enemy base area in Go Cong Province. The base, reportedly used for training recruits for the Viet Cong My Tho Province units, lay in an area nearly surrounded by waterways. (Map 7) The scheme of maneuver for the operation required a Popular Forces provisional battalion of Go Cong Province to move overland daring darkness to block the land escape route that the Viet Cong might use-if attacked-on tile southwest boundary of the reported base area. To assist the Popular Forces battalion in blocking on the west, helicopter gunships watched over an area into which ground troops were not allowed to move. The Mobile Riverine Force deployed into the area and moved into positions along the stream nearly encircling the enemy base area.
Entering the Vam Co River before daylight, five companies under the command of two battalion headquarters moved off the Vam Co and into the streams that formed a three-quarter circle around the enemy base. Once the companies had landed, the ATC's, augmented by all other assault craft available, moved to stations to prevent enemy movement across the small streams. An assault helicopter company stood ready at first light to move one infantry company as a reserve to brigade control. This company was set down before daylight by ATC's at a pickup zone adjacent to the barge-mounted artillery fire support base.
Early on 4 July troops were landed without encountering the enemy. By 1800 the sweeping operation had produced only three minor skirmishes; three of the enemy were killed, ninety-one detained, and two weapons were captured. There had been no U.S. or Popular Forces casualties. The U.S. battalions established dispersed ambush sites and shortly after dark began to encounter small groups of Viet Cong in a number of places. These encounters continued sporadically throughout the early evening; several of the enemy were killed and more were detained.
On 5 July, discovering cleverly disguised bunkers and so-called spider holes in which the enemy had escaped detection the previous day, U.S. troops made a more methodical search of the area.
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On the same day the Viet Cong who had been detained were sent to a combined interrogation center established by the Mobile Intelligence Civil Affairs Team and Vietnamese provincial officials at the province capital. Later, the interrogation reports provided information that the enemy elements encountered had been a platoon-size cadre and a newly recruited Viet Cong company. The cadre was reportedly equipped only with small arms, and the company had few weapons. The search for the Viet Cong continued through 5 July and ambushes were again established during the night.
The Go Cong operation ended on 6 July without casualties to U.S. or Popular Forces troops. Throughout the operation, the assault craft guarded the waterways, stopping over seven hundred native watercraft and screening the people, some of whom were held for further interrogation. On 4 July the reserve company had been inserted by the assault helicopter company into the area near. the COBRA zone. This company, operating under control of its parent battalion, had subsequently searched and maintained patrols and ambushes in the area. The impact of the operation on the enemy was not fully known until several days later when the interrogation center had completed its work and a Popular Forces company had re-entered the area to check information provided by the prisoners. Enemy losses included sixty-six killed, sixty-two prisoners of war, and five weapons. Under the Vietnamese government program of granting amnesty to Viet Cong who returned to the government, seven returnees, or Hoi Chanhs, were received.
The operation emphasized the importance of using a combination of land, air, and water transportation to take advantage of terrain, and the necessity for close co-operation with South Vietnamese officials and intelligence units. The combined transportation means enabled the Mobile Riverine Force to gain control over an area quickly. By seizing sampans along the waterways the Mobile Riverine Force prevented the enemy from using them to escape.
During this operation the Army initiated air resupply directly from the support LST. Previously supplies were moved from the LST by boat to a landing zone ashore, whence they were carried by helicopter to the field, an operation that required four separate transfers and considerable time. With the new method, loads were broken to unit size on the LST, each helicopter was loaded directly from the LST deck, and the material was delivered to the troop landing zone. To resupply two battalions using 10 UH-ID's (one assault helicopter company) required one hour and ten minutes.
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This time was bettered as the crew teamwork and the landing cycle on the LST's were smoothed out.
During the period of the Go Cong operation, another innovation was fielded by the Mobile Riverine Force that significantly increased flexibility. The first of several armored troop carriers was modified by adding a helicopter landing pad sixteen feet square over the troop compartment. An H-23 successfully operated from the new pad on 4 July and a LIH-ID on 5 July.
On 15 July Captain Wells requested that the Commander,
Naval Forces, Vietnam, obtain twelve Vietnamese national policemen of the river
police branch for assignment to Task Force 117. The experience of searching over
seven hundred native boats during the Go Cong operation highlighted the need for
more men to screen waterway traffic. Although no Vietnamese river policemen were
subsequently assigned, the force lead the co-operation of tile river police on
most operations.
On 21 July 1967 the Mobile Riverine Force concluded a two-day operation employing two U.S. infantry battalions in the southern part of Can Giuoc District. During the preceding thirty days, the force had conducted three operations in Can Giuoc District, killing 316 Viet Con, taking 15 prisoners, capturing 68 weapons, and detaining 337 people. This fourth operation was part of a program to strike at different sections of Can Giuoc until the whole district had been fully covered. Reports that company size groups of Viet Cong were in the area had been received by the combined intelligence center, the 46th Vietnam Army Regiment, and Can Giuoc District headquarters at Can Giuoc.
At 0545 on 20 July the 3d Battalion, 47th Infantry, and the 4th Battalion, 47th Infantry, boarded ATC's that joined in column with the heavy-gunned monitors and steamed west from the Mobile Riverine Base along the Vam Co River. From the fire support patrol base adjacent to the mobile riverine base the artillery supported the operation with two barge-mounted batteries of 105-mm. howitzers and one land-based battery of 155-mm. self-propelled howitzers from the 2d Battalion, 35th Artillery. At dawn Company C of the 4th Battalion, 47th Infantry, landed at the fire base as an airmobile or waterborne reserve force. Three ATC's stood by as water transport until a company of LTH-ID helicopters arrived to support the operation and to provide transportation of the reserves to any part of the battle area. When the convoy left the base
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ARMORED TROOP CARRIER WITH HELIPAD
it had a unique combat element. Both reconnaissance platoons of the two battalions had been designated Team Recon and were under the control of the 4th Battalion.
At 0700 the ATC's landed along a four-kilometer stretch of the east bank of the Song Rach Cat River, and 800 troops moved ashore under the watchful support of the monitors. The 3d Battalion, 47th Infantry, landed on the north beaches; the 4th Battalion on the south beaches, with Team Recon going in on the right flank. The landing was unopposed and all units quickly secured initial objectives beyond the beach, moving steadily to the east.
The operational area was bounded by the Song Rach Cat on the south and west and by the Song Nha Be on the east. On the north, a company of the 3d Battalion guided its left flank along Highway 229 running generally west to east. From the Song Rach Cat units moved slowly across the rice paddies, picking up all male Vietnamese, who were then evacuated and checked for identification at the combined intelligence center at Can Giuoc.
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Overhead the brigade and battalion commanders directed movement from Helicopters. Artillery observers and Air Force forward air controllers surveyed the battlefield, waiting to bring in supporting fire. By 1000 the companies had moved east approximately 2,000 meters without meeting the enemy while the Navy support craft moved up close behind them on the narrow streams with guns ready. At 1030, Company A in the center of the 3d Battalion formation reported fire from well-fortified bunkers. It was reported that 10 to 15 Viet Con- were sighted, but later a prisoner gave the number as 50 to 60. A point scout from Company A, operating well forward, was the only friendly combatant killed by enemy fire in the operation. As troops maneuvered to bring small arms fire upon the enemy, close supporting fire by 105-mm. and 155-mm. artillery was adjusted forward of the advance. Shortly after 1100 the first air strike began to lay 750 pound bombs and napalm on the Viet Cong bunkers. Of the five strikes called in on the target, three were directed while the artillery continued to attack.
Units began moving rapidly to block enemy escape routes. Companies B and C of the 3d Battalion to the north and south of the enemy deployed on a line facing the enemy. Company 13, 4th Battalion, 47th Infantry, maneuvered northeast across the rice paddy to block to the east. Company A of the 4th Battalion moved to join the block of the 3d Battalion's Company C on the south.
During the whole maneuver, the Navy ATC's and monitors were used to help find the enemy. Moving forward, the assault craft took up positions alongside the ground troops to add their fires to the battle and assist the infantry to cross the Rach Ong Hieu, a small stream. When Company A, 4th Battalion, 47th Infantry, arrived from the south at the Rach Ong Hieu the Navy ATC's provided lift across the stream, accomplishing in minutes what might have taken hours, and furnishing fire support as needed. By 1300 all blocks were in position with the exception of Company C of the 4th Battalion. At 1415 this unit was lifted by helicopters from the artillery fire support patrol base near the Mobile Riverine Base and landed to complete the block on the east next to Company B of the 4th Battalion. The encirclement of the Viet Cong was complete by 1515.
This encirclement was accomplished with a smoothly operating team of infantry, artillery, Navy and Air Force components. The tricky tides were known, and the boat commanders knew when and how far up a stream they could go to provide support. The infantry commanders maneuvered their troops across the rice pad-
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dies carefully, alert for booby traps and ambushes. Just in advance of lead elements, artillery delivered white phosphorus rounds which exploded 200 feet above the ground. Constantly re-adjusted, this marking fire insured that rapid and accurate artillery fire could be placed on the ground in front of the U.S. troops when they were engaged with the enemy. The Navy moved up close to the infantry positions to add the fire of the monitor's 40-mm. guns and 81-mm. mortars to reduce Viet Cong bunkers and machine gun emplacements. The Air Force and the artillery worked in close coordination, simultaneously laying on air strikes and artillery fire, while the Navy monitors maintained direct fire. When the helicopter company arrived in the battle area with Company C, 4th Battalion, 47th Infantry, it was able to land in a zone already secured by a U.S. ground unit, thus speeding the encirclement.
Action continued during the afternoon of 20 July, with units tightening their ring on the enemy as helicopters shuttled back and forth bringing a resupply of munitions and food. Seventeen Viet Cong dead had been accounted for by nightfall of the 20th. The pressure of artillery and small arms fire was maintained. The infantry positioned 90-mm. recoilless rifles and began to punch holes in the enemy bunkers. With darkness the Viet Cong fire became sporadic. U.S. troops maintained vigilance over the area during the night, using artillery illumination and allowing the Viet Cong no rest.
On 21 July a methodical sweep of the battle area revealed fifteen enemy bodies, one pistol, and seven rifles. More than eighteen bunkers had been reduced to rubble. Ten prisoners of war were taken, one of whom stated that on meeting U.S. troops the Viet Cong company had split into small groups and attempted to get out.
On 22 July the first helicopter barge was delivered to the Mobile Riverine Base. It was prepared for movement with the 3d Battalion, 34th Artillery, to the brigade forward command post at the barge-mounted artillery fire support base on 24 July.
On 24 July, in co-operation with the 3d Battalion, Vietnam Marine Corps, the 3d Battalion, 46th Vietnam Infantry Regiment, and GAME WARDEN patrol boats, the Mobile Riverine Force began operating in the northern part of Can Giuoc District in an effort to reduce the enemy threat to the district capital. (Map 8) At 0320 elements of the 3d Battalion, 34th Artillery, left the Mobile Riverine Base and went into position to support the operation at Fire Support Base TANGO. Elements of the 34 Battalion, 46th Vietnam
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Infantry, moved from their cantonment area at Can Giuoc directly east across the Song Rach Cat to land unopposed. They moved northeast through selected control points to the Rach Dua River without meeting the enemy.
The 2d Brigade troops approached the area from the south, moving up the waterways in ATC's protected by monitors. The 3d Battalion, 47th Infantry, reinforced by the reconnaissance platoon of the 4th Battalion, 47th Infantry, went ashore on the
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north bank of the Rach Vang River, moved north, and secured its first objectives without opposition. The 4th Battalion remained afloat near the mouth of the Rach Vang as the brigade reserve. Company C of the 4th Battalion was landed at Fire Support Base X-RAY, from which it would later be deployed as needed by helicopter. The waterborne units of the 3d Battalion patrolled the waters of the Kinh Lo, Rach Giong, Rach Ba Dang, and Rach Vang to detect the enemy. The 2d Battalion, 3d Infantry, 199th Infantry Brigade, also participated in the operation, landing two companies by air south of the Dong Dien stream. The Vietnamese Marine battalion was next to enter the operation, having been lifted by ATC's from loading points at Nha Be to beaches along the north bank of a stream called Muong Lon. The landings were unopposed, and all units quickly secured their initial objectives.
At 0915 one company of the 4th Battalion, 47th Infantry, was inserted by ATC's at a beach on the east bank of the Rach Ba Dang and at 1110, the battalion's remaining two companies were brought into the operation, one landing by helicopter and the other by assault craft west of the Rach Ba Dang. A few bunkers and booby traps were found and destroyed. Team Recon discovered freshly broken ground guarded by booby traps; further search disclosed an arms cache containing two 57-mm. recoilless rifles, one 75-mm. recoilless rifle, and one 81-mm. mortar with bipod. Other elements of the 3d Battalion, 47th Infantry, also discovered arms. The caches contained a total of sixteen individual and four crew-served weapons.
Throughout the day of 24 July no enemy was sighted. On the morning of 25 July the Vietnam Marine Corps battalion and the 3d Battalion, 47th Infantry, cleared the remainder of the assigned areas of operation. The marines consolidated in place along the banks of Muong Lon facing north, while the 4th Battalion, 47th Infantry, was taken aboard ATC's from beaches on the south bank of the Rach Dua and Rach Giong Rivers to begin movement south. In the northern operational area the 2d Battalion, 3d Infantry, had moved to the east, while the Vietnam marines held their position. The 3d Battalion, 46th Vietnam Infantry, had swung about to search again to the southwest, arriving at the original beaches about 1540. By 1715 all units were on their way to their home stations by water or air.
A Hoi Chanh who had rallied to the republic during the operation said that his unit had been directed to hide its weapons and equipment, break up into small groups, and temporarily cease operations in the Can Giuoc area. He said that his unit had oper-
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ated in Can Giuoc and Can Duoc Districts of Long An Province prior to battles with tire Mobile Riverine Force.
At the end of Operation CORONADO I on 25 July tire Mobile
Riverine Force, operating in eastern Long An Province, the Rung Sat Special
Zone, and Go tong Province, had killed 478 of the enemy since 17 .rune. The
force had been operating- in areas seldom frequented by tire South Vietnam Army
and other U.S. units.
The Mobile Riverine Force ended operations in the Long An area because of reliable intelligence indicating art enemy buildup west of My Tho in Dinh Tuong Province. The force received word on 25 July that the Mobile Riverine Base would move on 27 July from the confluence of tire Soi Rap and Vain Co Rivers to the vicinity of Dong Tarn. During the afternoon of 25 July ground forces were picked up by tire assault craft and returned to the Mobile Riverine Base. At 0200 on 27 July riverine assault craft began leaving the base for minesweeping arid patrol stations along tile route to Dong Tam. At 0550 the last ship of tire force was proceeding south on the Scri Rah River. Because of the slow speed of the towed APL moving against tire tide the journey took eleven and a half hours. This (lid not, however, delay the commencement of the operation in Dinh Tuong Province on 28 July. In just over forty-eight hours the Mobile Riverine Force was able to relocate a base supporting 3,900 men over a distance of sixty miles and to shift its area of operations a total of eighty-five miles to the area west of Dong Tam.
The Mobile Riverine Force was about to join tire largest force with which it would co-operate in a single operation in its Vietnam experience. Intelligence indicated that a Viet Cong force of several battalions threatened My Tho and Dong Tam; the plan was to attack simultaneously three of tire four Viet Cong base areas in Dinh Tuong Province from which an attack by the enemy might be staged. (Map 9)
On 27 July the 7th Army of Vietnam Division initiated operations designed to search for tire Viet Cong from east to west, north of Highway 4. The search would cover the territory around tire Ap Bac Viet Cong base arid end in the eastern portion of enemy base area 470. On 28 July the Mobile Riverine Force would move into the Cain Son base area; on 29 July one or more battalions of tire Vietnam Marine Corps would move into tire Ban Long base area. The U.S. 9th Division was to place the 5th Battalion, 60th
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Infantry (Mechanized) , under the operational control of the 2d Brigade for the Cam Son operation, and was to hold the 3d Battalion, 39th Infantry, on call at that battalion's Long An base camp. The 1st Brigade, U.S. 25th Division, was to arrive at Dong Tam on 28 July for commitment under the operational control of the 9th U.S. Division. The 7th Army of Vietnam Division was given the 44th Ranger Battalion by the commander of IV Corps for insertion by helicopter into the northwestern portion of Cam Son on 28 July. The U.S. Navy Task Force 116 (GAME WARDEN) was to patrol the My Tho River from My Tho to Sa Dec with thirty river patrol boats. To facilitate command and control, the U.S. 9th Division moved a forward command post to Dong Tam for the operation.
The Mobile Riverine Force operation in Cam Son began during the night of 28 July with the movement of the 5th Battalion, 60th Infantry (Mechanized), from its Long An base camp along Highway 4 to the town of Cai Lay. A battalion command post was established there as the maneuver companies continued south into the Cam Son area. As the mechanized battalion moved into the area of operations from the northeast, the 3d and 4th Battalions of the 47th Infantry moved by assault craft into the waterways in the southern portion of Cam Son.
Troop D, 3d Squadron, 5th Cavalry, minus the aerial rifle platoon, was operating with the Mobile Riverine Force for the first time. The troop had a reconnaissance mission covering the eastern Cam Son and western Ban Long areas on the brigade's flank. One rifle company of the 3d Battalion, 60th Infantry, was on call to the 2d Brigade for airmobile employment from Dong Tam.
Two assault helicopter companies were available to the 2d Brigade from II Field Force. At 0800 on 28 July they conducted feint landings at two landing zones just north of known enemy fortifications in northern Cam Son for the purpose of delaying enemy movement north until both the 5th Battalion, 60th Infantry, and the 44th Ranger Battalion could move into blocking positions near the feint landing zones.
On 28 July troops of the 7th Army of Vietnam Division north of Highway 4 received a little enemy fire and the Mobile Riverine Force encountered a few snipers in Cam Son. Troop D detected a squad of the enemy in the Ban Long area and killed five men with gunship fire.
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Throughout the late morning on 29 July both the 3d and 4th Battalions, 47th Infantry, discovered widely dispersed small enemy groups. From their movements it was deduced that these groups were trying to fall back to the north into a fortified area. As the 3d Battalion moved companies into this area from the north and south on the east bank of the Rach Ba Rai, the enemy resisted. Between the hours of 1700 and 1900, Company C of the 3d Battalion pressed north; small enemy groups moving northeast delayed the company's advance. Sometime during these two hours an ATC was hit by B-40 rockets and 57-mm. recoilless rifle fire; twenty-five men--Army and Navy-were wounded by fragments. The 5th Battalion, 60th Infantry, fired upon individuals and small groups of the enemy during the late afternoon and evening. None of the Mobile Riverine Force units were able to fix the enemy position and by 1930 contact with the enemy was lost. Most of the Viet Cong dead were found when the infantry moved into areas which had been attacked by artillery and helicopter gunships.
By the night of 29 July, the fact that the 7th Vietnam Army Division north of Highway 4 had found few Viet Cong and that the Viet Cong in central Cam Son had evaded major battle prompted General O'Connor, 9th Division; and Colonel Lan, commanding the Vietnam marines, to consider the probability that the enemy was in the Ban Long area. Although what the Mobile Riverine Force had learned about the enemy in central Cam Son was far from conclusive, the highly evasive tactics of the enemy encountered by the force was considered an indication that the Viet Cong units that the force had met might be protecting the movement of larger units into the Ban Long area. This was in keeping with the pattern of movement in southern Dinh Tuong Province, and while no enemy was detected in Ban Long by D Troop on 29 July, an enemy squad had been attacked there by gunships on 28 July.
At approximately 2000 on 29 July Colonel Lan selected a landing zone for his 3d Battalion of Vietnam marines to begin landing by helicopter in Ban Long on 30 July. The area selected by Colonel Lan as a likely enemy position was near the place where D Troop had discovered the enemy on 28 July.
When it landed on 30 July the 3d Vietnam Marine Corps Battalion met heavy resistance. The troops immediately attacked the enemy, who were in a wooded area north of the landing zone. More marines were airlifted into the landing zone, still under enemy fire. For five hours the marines attacked prepared Viet Cong de-
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fensive positions. The enemy armament consisted of light and heavy machine guns and mortars. The marines relied on helicopter gunships and artillery. The 3d Marine Battalion fought the enemy throughout the afternoon, taking a few casualties and reporting more and more of the enemy killed and more equipment captured.
General O'Connor, noting the long east-west belt of trees that I could provide concealment for the enemy, employed the 1st Brigade, 25th U.S. Division, east of the marines location to block movement of the enemy to the east. In mid-afternoon General O'Connor directed Colonel Fulton, commanding officer of the 2d Brigade, to assist the 3d Marine Battalion in evacuating casualties and in preparing for an attack against the Viet Cong. Colonel Fulton directed Lieutenant Colonel Bruce E. Wallace, commander of the 3d Battalion, 47th Infantry, to establish a blocking position west of the battle area, facing east, a maneuver accomplished by 2000. The 4th Battalion, 47th Infantry, in the field for three days, was returned to the Mobile Riverine Base with instructions to be prepared to deploy early on 31 July. The 5th Battalion, 60th Infantry, was detached to 9th Division at 1230.
During the action on 29 July several assault boats were hit with small arms, rocket, and recoilless rifle fire. The monitor most seriously hit suffered no major structural damage. Hits and minor damage were received by five other craft, but the boats were able to absorb punishment and remain in operation.
At approximately 2030 on 30 July, Colonel Lan requested illumination for a night attack against the enemy positions. The subsequent attack by the 3d Vietnam Marine Corps Battalion silenced several 12.7-mm. machine guns and inflicted losses on the enemy. The attack was stopped by the 3d Marine Battalion commander because his own losses here heavy. Illumination was maintained during the night; at approximately 0430, 31 July, the enemy counterattacked to the east, with heavy losses to both sides.
Later in the morning of 31 July, the 5th Battalion, 60th Infantry, was again placed under the operational control of Colonel Fulton. At 0835, the battalion went to the assistance of the 1st Squadron, Pith Vietnamese Army Cavalry, and the 44th Ranger Battalion, which had met the enemy while moving to assist the 3d Marine Battalion. By 0825 the 5th Battalion, 60th Infantry, occupied a blocking position northeast of the 3d Battalion, 47th Infantry, where it remained during the day. During the morning of 31 July, the 3d Battalion, 39th Infantry, also was placed under the operational control of Colonel Fulton, bringing the Mobile Riv-
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erine Force to four battalions and Troop D, 3d Squadron, 5th Cavalry. The 3d Battalion, 39th Infantry, landed south of Vinh Kim and searched west.
Reports from the 44th Ranger Battalion and 3d Marine Battalion indicated that the Viet Con, tentatively identified as the 263d Main Force Battalion, had dispersed during the predawn counterattack and were making their way south. Airborne reconnaissance by the 3d Battalion, 39th Infantry, revealed movement south in the direction of the village of Ap Binh Thoi.
Colonel Fulton directed the 3d Battalion, 39th Infantry, to conduct reconnaissance using helicopters southeast of the battle area and working west to Ap Binh Thoi. He directed Colonel Wallace to move his battalion southeast and to search the area as he closed on Ap Binh Thoi. This movement was initiated in midmorning and by 1700 both battalions were on the outskirts of Ap Binh Thoi. During that time Viet Cong were observed moving into Ap Binh Thoi in groups of twenty-five to thirty.
The 4th Battalion, 47th Infantry, augmented by elements of a Vietnamese field police force company, landed by ATC and entered Ap Binh Thoi. One company moved out to search northwest of the town while the rest of the battalion assisted the Vietnamese police in rounding up and interrogating people suspected of being Viet Cong. Several of the prisoners reported that the Viet Cong units encountered by the Vietnamese marines were the 263d Main Force Battalion and elements of the 514th Local Force Battalion. The prisoners were classified as Viet Cong when they confessed to having hidden their arms as they left the battle area during the early morning darkness. Company C, 4th Battalion, 47th Infantry, captured four men northwest of Ap Binh Thoi, all of them members of the 263d Main Force Battalion and one of them the battalion deputy commander. Of the more than 400 suspects detained by the National Police, 83 were from the 263d Main Force Battalion. The cordon around Ap Binh Thoi was completed by dark on 31 July, and no more of the Viet Cong were sighted.
The four-day operation, primarily because of the outstanding performance of the 3d Vietnam Marine Battalion, caused severe losses to the Viet Cong 263d Main Force Battalion, destroyed major fortifications in the Cam Son base area, probably thwarted planned enemy operations against Dong Tam, and eased the pressure on Highway 4. It also demonstrated the ability of U.S. and Vietnamese forces to work together. After the operation intelligence sources reported that the enemy had attempted to organize boats for a crossing of the My Tho River into Kien Hoa Province but were
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stopped by the cordon at Ap Binh Thoi and the river patrols. During the five-day operation on the My Tho River more than fifty patrol craft were employed; 283 Vietnamese watercraft were stopped and searched by naval craft from GAME WARDEN and the Mobile Riverine Force in the most ambitious attempt to control river traffic during the force's operations in 1967.
During operations from 28 July to 1 August, a large number
of soldiers in the 3d Battalion, 47th Infantry, developed foot trouble as a
result of spending five successive days on flooded land. The 4th Battalion,
which had had one night of rest aboard ships of the Mobile Riverine Base,
experienced a similar but lower rate of fungus infection and immersion foot.
The
Mobile Riverine Force Returns to III Corps
CORONADO III was conducted in the Rung Sat Special Zone from 5 through 17 August after the Mobile Riverine Base had moved from Dong Tam to an anchorage at the junction of the Soi Rap and Vam Co Rivers, The purpose of the operation was to disrupt possible Viet Cong attacks on shipping in the Long Tau channel. Although no attacks were made on shipping during the operation, the Mobile Riverine Force fought sporadically with the Viet Cong and captured some munitions.
The Commander of Naval Forces, Vietnam, provided the following evaluation of the Mobile Riverine Force through CORONADO III:
Perhaps the best evaluation of MRF achievements can be
attained by examining the results of frequent riverine operations in Can Giouc
District of eastern Long An Province. In its first operation in this area on 19
and 20 June, the MRF became engaged in the toughest fight it has experienced to
date. Over 250 of the enemy were killed at a cost of 46 US KIA and 140 wounded.
As the MRF returned to Can Giouc for further operations in late June, during
July and again in late August, it never failed to make contact with the enemy.
The size of the enemy units encountered has grown smaller and the percentage of
prisoners taken versus enemy killed has risen steadily. Increasingly large
caches of weapons have been uncovered. River Assault craft now move freely
through areas where two months ago ambush with RPG-2's or recoilless rifles
could be anticipated at any moment. In summary, it appears that a VC haven and
stronghold, rarely ventured into by ARVN or FWMAF in the past, has been reduced
to an area containing only scattered and poorly organized VC Guerillas.
CORONADO IV was conducted from 19 August through 9 September, with operations in Long An, Co Cong, and Kien Hoa
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Provinces. On 20 August the assault craft left the Soi Rap and Vam Co River anchorage of the Mobile Riverine Base just after midnight and landed troops at 0904 in the target area north of Ben Luc on the Vam Co Dong River, a distance of over fifty kilometers. (Map 10) Because waterways off the Vam Co Dona in the target area were not navigable, the two infantry battalions were
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landed to move west and search the area on foot. Company C of the 3d Battalion, 47th Infantry, remained at a pickup zone near the fire support base at Ben Luc as an airmobile reserve. To intercept enemy forces, the 334th Aviation Company's supporting gunships maintained surveillance of the areas forward of the infantry battalions.
At 1400 the movement of the 3d Battalion, 47th Infantry, forced an enemy platoon from a lightly fortified area. The gunships were placed under control of the battalion commander, and were directed against the enemy, who was attempting to evade contact with the ground troops. The gunships sighted the enemy troops and took them under fire, after which the reconnaissance platoon of the 3d Battalion, 47th Infantry, was brought in by helicopter to mop up. The platoon encountered some fire from snipers and co-ordinated fire of the supporting gunships on the enemy. A search of the area revealed that thirty-four of the enemy had been killed. From documents found in the area the enemy was identified as an element of the 506th Local Force Battalion.
The success of this operation was attributed to the surprise achieved by the ground troops landing from the river; the Viet Cong were forced into the open where gunships could take them under fire. During the operation, which ended on 22 August, the Mobile Riverine Force suffered six wounded and the enemy lost fifty-nine killed.
For the remainder of August and the first week of September, the Mobile Riverine Force operated in Can Giuoc District, encountering minor enemy resistance. On 7 and 8 September the force operated in conjunction with the 1st Brigade, 9th Division, in the southeastern part of Nhon Trach District of Bien Hoa Province and the northeastern part of the Rung Sat Special Zone. Few Viet Cong were encountered but a cache containing medical supplies, eight crew-served weapons, and ninety-seven small arms was discovered. This operation was one of the first in which Colonel Bert A. David commanded the 2d Brigade. Colonel David assumed command as Colonel Fulton, promoted to brigadier general, became assistant division commander of the 9th Infantry Division. General Fulton was responsible to General O'Connor, now commander of the 9th Division, for operations in the Mekong Delta. At this point in early September the Mobile Riverine Force had operated extensively in the III Corps provinces north of the Mekong River. As the second week of September began, the force prepared to return to Dinh Tuong, an area of great interest to the senior adviser of the IV Corps Tactical Zone.
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