5RAR Association Website
operations conducted 1966-67


australian infantryman's combat badge

6 October - 10 October 1966

By Captain Robert J O'Neill MID

While we had been busy clearing Phuoc Tuy of Viet Cong forces, American planning for the co-ordinated clearance of the entire Third Corps area had progressed to the stage at which a major influx of troops was due to arrive. These men comprised the Third Brigade of the Fourth Infantry Division and they were to land at Vung Tau in the first days of October 1966. Their initial task was to secure the northern sector of Route 15 which lay in Bien Hoa Province. They were to operate from a base fifteen miles to the south-east of Bien Hoa city, Bear Cat. This effort aimed at making Route 15 a 'green' route, one over which allied traffic could move at will without heavy armed escort. Once this had been achieved it would be possible to use the developing harbour facilities of Vung Tau to a much greater extent. Large numbers of men and huge amounts of additional material were scheduled to come into the country during the following few months and these would have congested the port of Saigon unduly. Moreover, the Americans were increasing the size of their installations at Bien Hoa and at Long Binh nearby and both of these places were served by the direct connection of Route 15 to Vung Tau.

However, to make these plans possible the hold of the Viet Cong over Route 15 had to be broken. Taxation activities had been very lucrative because of all the wealthy Saigon businessmen who drove down Route 15 to spend weekends and holidays at Vung Tau. Viet Cong attacks on the scattered Government posts along the road had increased during 1966 and it was apparent that the Viet Cong were making a major effort to continue to extend the interdiction of the road. A special point of interest was the village of Phu My, which just lay to the south of Phuoc Tuy-Bien Hoa boundary. This village was close to the centre of the Viet Cong controlled sector and was an obvious point for the Viet Cong to concentrate against. Phu My had been occupied by the Japanese during World War 11, and they had built an airstrip at the rear of the battalion-sized fort on the northern edge of the settlement. The airstrip had fallen into disuse, but the fort had been well maintained as a matter of necessity. The Viet Cong were able to move forces against the Phu My garrison from either side of the road. On the south-western side lay the Rung Sat with its countless creeks, footpaths and hiding places amongst the mangroves. On the north-eastern side was a thick jungle which covered a network of tracks leading down to Phu My from the Hat Dich base area.

During August 1966, 274 Regiment had made attacks on Phu My, harassing the post with mortar fire and ambushing reinforcement and supply convoys on their way to the fort. We knew that the commander of the 274 Regiment intended to wipe out the Government force at Phu My as soon as he could and so there was some urgency in dealing with the Viet Cong along Route 15. The Americans had stationed a brigade of the First Division at Bear Cat to began domination of the northern sector and to pave the way for the Third Brigade of the Fourth Division.

The safe passage of this brigade from Vung Tau to Bear Cat required the establishment of temporary control over the entire length of the road for several days. The convoys were a tempting target to the Viet Cong, so the force protecting the road had to be strong enough to counter a Viet Cong attack of battalion strength at any point and also had to be capable of rapid deployment to meet a regimental attack. Of course the Viet Cong did not have to elect to take massive action, for they could have cut the road and done considerable damage by the use of mines and booby traps, perhaps covered by a few snipers hidden in the jungle nearby.

Four battalions were provided to secure the road - three from the 173rd Airborne brigade and one from the Australian Task Force. Because the Sixth battalion had just completed an arduous sweep through the Dinh hills, The Fifth Battalion was assigned the task and Colonel Warr was warned for the operation in early October. The battalion was to be responsible for the southern sector from Ba Ria to Phu My while the 173rd Airborne Brigade took the sector to the north of Phu My.

The southern sector was threatened from two areas in differing ways. Bordering the road on both sides were strips of coastal plain from one to several miles wide, linking the mangroves of the Rung Sat on the south-west with the hills on the north-east. These flat areas were covered mostly with a low scrub which gave protection to any ambushing party. The scrub terminated to within a hundred yards of the road for much of its length, and was sufficiently thick to give cover from air observation so that withdrawal routes for the ambush party would be difficult to locate. Hence it was important that these areas were regularly patrolled to a distance of several hundred yards back from the road.

The second area from which the road was threatened was the long spine of the hills on the north-eastern side. These consisted of the Dinh hills which ran for six miles along the road, and       Nui Thi Vai and Nui Toc Tien. This latter pair were joined by a pass which climbed to five hundred feet above the plain which lay close to sea level. The Dinh hills had just been cleared by the Sixth battalion and close surveillance had been kept over the access routes which lead into them from the Viet Cong base areas.  Hence we could be fairly certain that danger would not come from the Dinh hills, Nui Thi Vai on the north-west and Nui Toc Tien on the south-east, presented a more difficult problem because neither had been cleared before.

Nui Thi Vai rose to over fifteen hundred feet and commanded a particularly long section of Route 15 because the road swung around the base of Nui Thi Vai to change its direction from north-west to north as one proceeded towards Phu My. Nui Toc Tien was fourteen hundred feet high, but its position to the east of Nui Thi Vai robbed it of much of the view over the road. Nui Thi Vai was a rectangular mountain with straight, deep faces to the north, east and west and a long ridge running out in a series of lesser peaks to the south. Because of this rectangular configuration, the easiest lines of ascent lay up the spurs on the north-west, the north-east, the south-west and the ridge from the south. Therefore this points were likely places for finding any Viet Cong who happened to be on the mountain. The southern ridge included two peaks of five hundred feet, separated by low saddles. The more southerly of the two was crowned by twin peaks separated by three hundred yards and a drop of sixty feet in between. From here,  the ridge ran down steeply to sea level at the foot of another hill, Nui Ong Trinh, 750 feet high. Nui Ong Trinh approached to within a mile of the road while most of Nui Thi Vai was within 81mm. mortar range of the road. Mortaring was the chief method of attack which the Viet Cong could use with regular impunity against the road. from positions up on Nui Thi Vai they could direct their fire by direct observation of the bomb bursts. They could then retreat from our counter bombardment in an instant into caves or tunnels and be ready to emerge again when the next likely target appeared on the road. Not only could a Viet Cong force with mortars on Nui Thi Vai have damaged road traffic but they could have seriously threatened any troops down on the plain who were patrolling near the road.

Nui Toc Tien did not present such danger because it did not command very much of the road. Not only was it masked by Nui Thi Vai, but its configuration, a long ridge with five main peaks, ran parallel to the road and none of the high ground was sufficiently close to the road to be within mortar range. Of course it was possible for the Viet Cong to set up mortars on the flat country along the road, but it would have been much more difficult for them to have achieved accurate fire than on the hills and their positions would have been less secure than in the rocky caves which the hills offered.

Several Viet Cong track systems ran through the area, and these were important because of the possibility of finding some base camps which formed part of their supply channel between the rung Sat and the Hat Dich area. A broad track, the size of a two lane highway ran through the main pass, between the Dinh hills and Nui Toc Tien. Another track, although for foot use only, ran up over the pass between Nui Toc Tien and Nui Thi Vai, and then for several miles through the jungle to intercept the main track which ran between the Hat Dich area and the Dinh hills to Ba Ria. Several tracks ran around the western side of Nui Thi Vai from different points on Route 15 between Phu My to the north-west and the village of Ong Trinh to the south-west.

The jungle clad slopes of Nui Thi Vai rose steeply from the plain with an average gradient of one in three. From the relatively bare summit one could see individual vehicles moving along Route 15 for ten miles. from this vantage point the Viet Cong could learn the composition of military and civilian traffic using the road, taxation points could be controlled and, in the particular cases of bridges and culverts which had been mined by the Viet Cong, the right instant for detonation could be seen. Increasing allied pressure on the Viet Cong in September had prevented them from making extensive use of the hills during the weeks before our operation, and we did not expect more than a company of Viet Cong on Nui Thi Vai, although it was always possible that the security of the American intentions to send a brigade along Route 15 had not been perfect and that a main force regiment would be tempted to strike at such a prize.