Operation Giant Slingshot: A History (Part 6)
In February (1970) it was determined that the Navy operated LCM-8s
from Ben Luc could transit the rivers unescorted when traveling in pairs. Escorts had been
necessary until that time to provide navigational aid and fire support. Since LCM boat
captains were now thoroughly familiar with the territory and the boats fully capable of
protecting themselves. The decision was made to utilize the boats available for duties
other than escorting LCM-8s.
The last week of January and the first part of February saw extra precautions being taken
with the coming of Tet. Tet marks the beginning of the lunar new year and means a new
lease on life, time to have fun, buy new clothes, and exchange gifts.
The effect of Slingshot was that since Tet and the two days following are National
holidays, all of the VNN boat crews had at least one day off to visit their families. All
the Vietnamese civilian workers on the bases were gone for the 3-day period, which
included hootchmaids and galley personnel. Special watchbills were implemented during this
period. There were no unauthorized absentees during the holidays.
During the 24-hour allied truce on 5-6 February there were no enemy cease fire violations.
However, following the allied truce -and still during the 96 hour VC/NVA declared truce -
the base at Tra Cu was mortared, resulting in 1 U.S. KIA and 12 U.S. /VN WIA. Seawolves,
Blackponies, and artillery strikes in the area silenced any further activity.
12 February marked the end of another era. The YR-9 was pulled from her slip at Ben Luc
departing for Nha Be, after serving nearly 10 months as the NOC for CTG 194.9, serving as
a repair facility and work shop and providing berthing for approximately 35 men.
Only three weeks after T-36 had been mined in Go Dau Ha, there was another incident. This
time, at 130220 February, the VC sappers destroyed the Go Dau Ha bridge. As witnessed by a
sentry at the ATSB, one of the bridge supports raised up slightly before toppling south
into the river taking approximately one-half of the roadway with it. The only resultant
damage to the ATSB was minor damage to the stern of a PBR as a falling piece of material
struck the boat.
The Army engineers were on the scene immediately to assess the damage and begin making
plans for rebuilding of the bridge, hopefully to be completed within about two months.
Moving further south to the Tra Cu area, operations began on the night of 15 February in
the Kinh Gay Canal, with PBRs from RPG 53 setting WBGP in the eastern section. At that
time units could transit the entire length of the canal only during high tide and on step
due to the reduced water level of the canal. Turnaround points had been dug every 1000
meters or so, but had started to fill in with silt. UDT 11 was designated to clean out
these turnaround points in April and May while the water level was still low.
The Navy's area of responsibility in GIANT SLINGSHOT is not the only area being turned
over to the Vietnamese; the U.S. Army is gradually redeploying as the ARVN units are
becoming capable of accepting additional areas of responsibility. This was the case in
lower Long An Province when 6th/31st Battalion moved out of Can Giouc to the Ben Luc area.
Mediation with Cambodia in mid-February led to the return of the remains of the personnel
killed in a helo crash in April 1969 inside the Cambodian Border. Arrangements were made
by CDR Sigmond to receive the remains at the intersection of highway 1 at the Cambodia
Border, 10 km west of Go Dau Ha at 201300 February 1970. The entire evolution, which
included close coordination with the U.S. Army, RF/PF, and Cambodians ran without
Engagements with the enemy during the month of February were down considerably from
December and January, which can be attributed to the termination of the winter offensive
that was strong in the previous two months, but was subsiding in February.
The beginning of March saw the Naval Research Development Unit, Vietnam, (NRDU-V)
conducting tests on several new projects in the Ben Luc, Tra Cu, and Tuyen Nhon areas.
Testing in this environment provides results with more realistic data than can be obtained
in the laboratory. Included in these experiments was the squeeze bore machine gun which
squeezed .50cal ammunition to .30 cal size as it left the barrel. The new ammo being
tested consisted of 5 projectiles stacked on top of each other and when fired would emerge
as 5 separate projectiles. This idea was ideal as the range, compared to the .50 cal, was
greatly reduced and the area of coverage was increased 5-fold.
Another project was the Duval Detector-designed to detect false bottoms on sampans, in
which illegal merchandise could be transported.
Third was the contraband detector - a concept of employing a special radar to detect metal
objects - contraband-being transported in waterborne craft. All of these projects proved
worthwhile, but each, after it's test in the field, required some modifications.
The policy of requiring escorts while transiting the Vam Co Dong and Vam Co Tay was again
modified in April. Craft that did not carry their own armament would require an escort. A
new concept that of the "transit coordinator" or river pilot was adopted. A boat
having it's own guns would pick up a pilot at the USS Sphinx and travel to its destination
- the pilot's job being to help with the navigation and coordinate with the NOC in case of
This concept eliminated a great a great number of boats from daytime use and enabled
additional boats to be utilized at night to set WBGP as part of the effective interdiction
Another step in the Vietnamization of Operation GIANT SLINGSHOT took place when 15 U.S.
RAC boats of RivDiv 151 departed the AO on their way to Barrier Reef operations, in
exchange for 15 boats of River Interdiction Division (RID) 40. The shift took place on 4
March, and shortly after their arrival, RID 40 was turned over to the Vietnamese during a
small turn over ceremony at Ben Luc. The home of the newly formed VN division was to be at
Go Dau Ha, replacing RPG 53.
Due to the increased operations of the RF/PF troops in the Moc Hoa AO, the river area
available for the boat operations was greatly reduced during the early part of March. With
this in mind it was determined that the PBR division assigned to Moc Hoa was adequate to
patrol the AO. Consequently RAID 70 units were redeployed to Tan An. The enemy threat had
also subsided, as the enemy had reportedly shifted its position towards the west in
Only a week after shifting the RAID, a shift of RivDiv's saw RivDiv 571 replacing 511 in
Moc Hoa, in preparation for 511 turning over to the Vietnamese at the end of March. The
shift of both RivDiv's was completed on 19 March.
At 182345 March the first of 4 mining incidents to occur in 2 weeks took place in Go Dau
Ha. An Alpha boat HQ5144 was in WBGP when a mine exploded which resulted in the sinking of
the boat. Fortunately the only resultant casualty was a broken leg. Salvage operations
were commenced immediately, but due to the boat's weight of 90 tons, work was delayed
until a second salvage craft arrived on scene to assist. The craft was eventually raised,
holes patched and then towed to Dong Tam for repairs.
The second incident occurred at Ben Keo on March 20th at 0120 when an alert watch spotted
a swimmer near the base. GQ was set, grenades were thrown in the water and boats took the
area under fire. The results were 2 VC sappers KIA and one mine retrieved which was
approximately 40 pounds of explosive. A great deal of credit was given to the guard who
spotted the swimmer.
Third was the successful sapper mining incident of two Army LCM's, this time at Tuyen
Nhon, a base that had not been attacked in many months. Intelligence during this period
stated a high point in enemy activity would commence at 0200 on 1 April. It was 0220 when
the mining incident occurred - however enemy activity was not confined to that location.
The cities of Moc Hoa, Go Dau Ha, Tra Cu base, and an area north of Ben Keo all received
incoming rounds within one hour of 0200.
The two Army LCM's at Tuyen Nhon were loaded with ammunition, which fortunately did not
detonate. No one on board was injured. Salvage operations commenced the same day. Both
craft were raised and patched and towed to Saigon for repairs within one week.
The 4th mining incident - and second at Tuyen Nhon in three days - took place 10 km west
of the ATSB, when an alert crew member of a VNN RAC boat spotted a mine attached by a line
to his boat. The crew immediately cut the line, towed the mine cautiously across the river
and secured it until the explosive ordinance disposal (EOD) team arrived on the scene to
dispose of the charge. This, like a previous mine, weighed approximately 30-40 pounds.
While discussing mining incidents, the Go Dau Ha bridge, which was mined on 13 February,
still had not shown signs of new construction, which was originally scheduled to be
completed in 90 days. The Army did, however complete a one lane pontoon bridge across the
river just north of the ATSB at Go Dau Ha, on which their many truck convoys could pass.
Unfortunately the Navy, and other afloat assets, could no longer transit the river freely,
having to wait for the bridge to be opened - a function that was controlled by the ARVN's.
Several conferences were held to coordinate the opening of the bridge. The results were
that it would be open for 1-2 hours per day, and in case of emergency.
Following the mining incidents during the first days in April, which seemed to mark the
highpoint of a relatively short offensive campaign by the Viet Cong/North Vietnamese Army,
the next three weeks saw very little activity throughout the GIANT SLINGSHOT area other
than the minor incidents, in which units in waterborne guardpost spotted movement of
lights on the beach and took them under fire. This was normal procedure since their
observations were curfew violations.
In preparations for the forthcoming turnover of the operation to the Vietnamese Navy on 5
May, it was decided to establish Vietnamese Task Unit Commanders at as many of the ASTB's
as possible. With the arrival of ten PBR's of RPG 54 at Tan An, on 15 April 1970, the ten
existing RPG 53 units shifted to Ben Keo, establishing another Vietnamese Task Unit
Commander. This brought the total number of bases under Vietnamese Task Unit Commanders to
four - Ben Keo, Go Dau Ha, Ben Luc and Tan An.
After arriving at Ben Keo, RPB 53 relieved River Division 594 who in turn proceeded to
Tuyen Nhon to relieve River Assault Division 153. After this turnover, the Alpha boats of
RAD 153 were underway for Tra Cu to take over from River Division 552, which was scheduled
to depart GIANT SLINGSHOT to chop to CTG 194.4 at the USS Benewah (APB-35) in preparation
for turnover. The shifting of assets , with the exception of River Division 552, was
completed on the 25th of April.
To summarize, GIANT SLINGSHOT units are located as follow:
|Area Of Operation
||South of Tan An
|River Patrol Group 54 (10 PBRs)
||North of Tan An
|River Division 594
|River Division 571
||South of Ben Luc
|River Patrol Group 53 (10 PBRs)
||North of Ben Luc
||Go Dau Ha
|River Patrol Group 53 (10 PBRs)
|River Division 552
||Remains at Tra Cu
During mid April another project was conducted in CTG 194.9's area of operation. This
project utilized several highly trained dogs for base waterfront protection. They were
capable of detecting any swimmers who might attempt to approach the base, and once
detected would pursue them in the water. The dogs were initially located at Go Dau Ha and
later moved to Ben Keo. During their three week testing period there were no swimmer
By the 25th of April plans were being developed at a higher level for a complete new
operation that was about to unfold. On the 26th plans were being made by CTG 194.9
concerning employment of boats on the Vam Co Tay River in support of ground advance in to
the Crow's Nest area of Cambodia by ARVN soldiers, who were planning to sweep east in the
Parrot's Beak. As stated in President Nixon's speech on Thursday, 30 April 1970, the
purpose of ground operations was to sweep through the border region inside Cambodia which
the Viet Cong/ North Vietnamese Army had been using as a planning / staging area for
frequent attacks into South Vietnam and then as a sanctuary into which they could retreat,
with no fear of being pursued.
Many assets were to be employed initially as a blocking force along the 40 kilometer
stretch of the Vam Co Tay from Long Khat, northwest of Moc Hoa at ET 920072, to XS 070660,
about 9 kilometers Southwest of Moc Hoa. In order to provide sufficient boats to cover the
area effectively, a double shift of assets was initiated involving River Division 571,
located at Moc Hoa, river division 594 from Tuyen Nhon, River Division 552 from Tra Cu,
RPG 53 from Ben Luc, RPG 54 from Tan An and RPG 56 chopped from CTG 194.9, who reported to
the task unit commander, LT PAUL DONALDSON, Commander River Division 571 at Moc Hoa. River
Division 551 was chopped from CTG 194.4 to assume responsibility of the Tuyen Nhon area of
operations on the Vam Co Tay, making a total of eighty boats assigned for the operation.
LT R..J. CARLSON Commander River Division 552, was assigned as liaison officer between the
ARVN's and the Navy at Moc Hoa.
The initial blocking force reported on station at 291300H April, after being delayed
several hours by the newly constructed pontoon bridge across the river just south of Moc
Hoa. The drive through Cambodia proceeded according to schedule with no major
difficulties, until they were finally providing a blocking force in the Tuyen Nhon area of
operation, at which time the Task Unit Commander was shifted to LT T.W. FRENZINGER at
After all objectives had been met in Parrot's Beak, the operation was terminated at 061600
May. Results were as follows:
a. Friendly casualties 67 killed in action and 332 wounded in action.
b. Enemy casualties were 1202 killed in action, 233 prisoners of war,
1146 individual weapons captured and 3 vehicles captured.
As this operation was being conducted, final preparations for the change of command
ceremony on 5 May, in which Operation GIANT SLINGSHOT would be turned over to the
Vietnamese Navy, were being made at Ben Luc.
At 051000H May the ceremony commence, with Vice Admiral ZUMWALT and Commodore CHON, plus
numerous other distinguished guests in attendance. Following the inspection of the colors
and the invocation, Commander SIGMOND and his relief, Lieutenant Commander TIEU made their
remarks. The GIANT SLINGSHOT Flag was then passed from the United States Navy to the
Vietnamese Navy marking the turnover. ADMIRAL ZUMWALT and Commodore CHON, the Vietnamese
Chief of Operations, each made remarks.
The turnover of operational control of Operation GIANT SLINGSHOT to the Vietnamese marks
another giant step in the turnover program. The accomplishments and the successes are a
tribute to those who have served so well during the past 18 months.
Along with the turnover came a new name for the operation "Tran Hung Dao II".
Designated TG 214.1, under the command of Commodore Phong, CTF 214, with Lieutenant
Commander TIEU designated as the on-scene commander.
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