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Operation Giant Slingshot: A History (Part 5)

Only a few days later another RivDiv was removed from the forces in GIANT SLINGSHOT. In preparation for turnover of two more PBR RivDivs to the Vietnamese in March, RivDiv 592 from Go Dau Ha was chopped to CTG 194.4. However, RivDiv 551 was assigned to continue the interdiction efforts in the Go Dau Ha operation area.

The tempo of enemy activity increased so rapidly in the Tuyen Nhon, Moc Hoa area between 13 and 15 December that plans were being made to shift additional assets to that area. Boats in WSGP and those transiting at night were taken under attack numerous times with B-40s, automatic weapons, and small arms fire. There was even one day-time enemy initiated firefight near Tuyen Nhon which had become uncommon, compared to activity of 6 months before. It was believed that the 58th NVA/VC Regiment staging in Cambodia was preparing to move south across the Vam Co Tay River to base camp 470.

On 20 December COMNAVFORV executed a contingency plan, which started a succession of events. The double shift on the left river consisted of the newly arrived 551 units moving from Go Dau Ha to Tuyen Nhon for patrol on Barrier Reef East. COMRIVDIV 152 also relocated units to stage out of Tuyen Nhon along with 551, under CTG 194.4. Moc Hoa was beefed up with 10 RAID 70 boats, to cover the river east of Moc Hoa while the PBR's concentrated on the narrower river to the west. For four consecutive nights, the ASPB's and PBR's, took fire from the enemy, which resulted in 6 RAC boats and 2 PBR's damaged and the loss of 4 lives. In order that the same VNN units didn't remain in Moc Hoa indefinitely, a two-week rotation between RAID 71 boats was scheduled.

After taking 551 out of Go Dau Ha, only 3 tango boats remained. This was not sufficient to provide adequate coverage of the river. RivDiv 594 in Ben Keo was split, with 4 boats filling the vacancy in Go Dau Ha leaving 4 to operate in Ben Keo and 2 down for maintenance. This concept would provide adequate assets, at least temporarily, since the enemy threat appeared to have shifted away from the area.

The final shift of assets saw Det 7 move from Tay Ninh to Ben Luc. The Det had been staging out of Moc Hoa during the hours of darkness and returning to Tay Ninh in the morning. The move to Ben Luc was to be only an intermediate stop, while the air facilities were being completed at Moc Hoa for Det 7's new home base.

Shortly after Christmas CTG 194.9 was taxed with a mission to determine the feasibility of transiting a series of canals leading west from Tan An and leading to Dong Tam. To accomplish this 2 PBRs were used to transit the canals, while the embarked hydrographic team took depth readings, width of channel, tides etc. As this is the first time units had transited this area the Seawolves reconned the area just prior to the boat's transit. They staged nearby so they were immediately available should an emergency arise. This operation, "Operation My Dien" was completely successful in all respects, which demonstrates the versatility of GIANT SLINGSHOT capabilities, even on short notice.

The holiday season was at hand, and truces were declared by both sides for 24 hours on Christmas and New Years days. This called for the combined forces not to make any aggressive actions, during the truce, but were free to react defensively to any interdiction attempts made by the enemy.

Vietnamization has been the name of the game in the past and continues to be an important goal. To date the efforts of GIANT SLINGSHOT had been a prime example throughout the delta. The Vietnamese were now able to repair nearly an entire PBR and RAC boat without U.S. help. They learned to over-haul engines and pumps, do fiberglass patchwork, repair electrical casualties, and repair their weapons. The electronics field lagged slightly behind the rest, but excellent and rapid progress continued to be made in the technical area.

In January, just like December and November, numerous VIPs visited Ben Luc and the other ATSUs in GSS. There had been a full cross-section of visitors, including DEPSECDEF, CNO, Admirals from various commands, U.S. Army and Air Force Generals, Astronauts, Senators, Congressmen and numerous others. Each is given a tour of the base at Ben Luc, including the maintenance shops, the river craft and the Vietnamese dependent housing area, following by a briefing by CTG 194.9 and his VN deputy, the Naval Intelligence Liaison Officer, the OINC of NSA Det Ben Luc and his VN counterpart. From here the visitor is flown to an ASTB to see at first hand the austere way of life and is briefed on the operation in the immediate area.

With the beginning of the new year came the commencement of a new operation called "Deep Channel II" the concept was to link the industrial Canal leading from Tuyen Nhon with the Kinh Gay Canal extending west from Tra Cu. It was determined that by the use of MK-8 explosive hose on the 28,000 feet required to connect these 2 canals would be most feasible method of completing the task. One estimate stated it would take 18 months and five million dollars to empty a government dredge to do the required work.

Consequently the operation was undertaken by UDT 12, 22 underwater demolition experts, who completed the job 40 days and $500,000 later. The canal after completion measured 25 feet wide and five feet deep with turnaround points for a PBR every 1000 meters. This canal in the rainy season would not only serve as another waterway on which to conduct interdiction patrols, but could serve as a shorter route for the Vietnamese to get his rice and other merchandise to market in Saigon, as the distance will be cut by 80% between Tuyen Nhon and Tra Cu.

A small ceremony was held at the demolition site for the blowing of the final charge linking the 2 canals. General Abrams, COMUSMACV, was on hand to detonate this historic charge.

On the night of 9 January an ever alert watch-stander on the Mobile base at Tan An sighted an object in the river adjacent to the base moving slowly upstream against the current. After immediately informing other base defense personnel, he threw a concussion grenade toward the object which triggered a secondary explosion producing a 40 foot water spout. Boats scrambled to search for possible additional mines or evidence of sapper activity, with negative results.

The enemy's next attempt by a sapper unit was unfortunately successful at Go Dau Ha. At 210130 January a mine detonated between the galley Ammi and T-36 moored outboard of it. As a result T-36 was sunk with the loss of 2 American lives and the damage to the Ammi required extensive repairs at the repair facility at Nha Be. CSB-3 was deployed from Ben Luc at 210200 en route to the scene to assist in salvage operations, which began at first light. Baby Giant (the combat salvage boat) was able to finally pump out enough water to raise and beach the sunken tango boat, after the Ammi had been removed.

Because of the large hole blown in the well deck it was decided not to attempt to salvage the entire boat, but rather cut off and save the flight deck and the stern section with the engines, along with the gun tubs and other salvageable material such as bar armor. A YLLC, large salvage craft, from Vung Tau assisted Baby Giant for the remainder of the heavy salvage operations.

This utilization of the CSB is just one of many examples of her usefulness on the Vam Co Tay and the Vam Co Dong Rivers. With her capabilities of lifting 18 tons of a max height of 18 feet, conducting welding and cutting operations, utilizing her diving equipment and qualified divers to perform minor underwater repair, and even act as a fire boat if the need arises, the salvage craft was continually rotated among the ATSB's to assist in projects providing added security to the bases or helping to make the base just a little more habitable.

Intelligence that had been gathered of late, indicated an increased tempo of enemy operations in the Angel's Wing area of Cambodia, adjacent to Go Dau Ha. To counter the threat, the split RivDiv, presently there, would not be sufficient, therefore the decision was made to send 10 PBRs of RPG 53 from Tan An to Go Dau Ha which would allow RivDiv 594 to operate at full strength in the Ben Keo area.

This move marks another of many firsts in GIANT SLINGSHOT. A Vietnamese officer was assigned as a Task Unit Commander with all the responsibility thereof, including the important job of base defense officer. As may be expected there was a few minor problems to be overcome during the initial days, but within a week the transition was completed and all operations were running very smoothly.


To wrap up 13 months statistically the operation could account for 1089 firefights, 13 mining incidents, 254 munitions caches captured totaling 140 tons, 2,055 enemy KIA, 230 enemy captured in action, and 158 U.S./GVN KIA.

So far, requirements for the boats to provide escorts for units transiting the rivers has not been mentioned. As the months passed and enemy activity along the rivers decreased, the number of units requiring escorts had been ever increasing. Typical examples of units requiring escorts were the Army tugs and barges transiting to Moc Hoa and Ben Keo from Saigon at 3 day intervals, the RMK moves from Vung Tau to locations in SLINGSHOT, and any other units that may be traveling on the rivers alone.

The Army recognized the success of the river convoys. It is a known fact that the convoy concept tends to pacify the area adjacent to the highway; the same results could be attained on the river. The results were very promising. Knowing that the convoys were being protected, slowly the river traffic began joining the convoy for mutual protection.

A second, and less obvious goal was realized in the ability to account for sampan traffic. Before if 10 sampans left Tra Cu heading north and only one reached Go Dau Ha, the disposition of the other nine was not known.

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