OP Manhattan

Operation Manhattan (23 April - 7 June 1967) was a multi- brigade search and destroy operation conducted to destroy Viet cong forces in the Boi Loi-Ben Cui area. The secondary mission of the operation was to destroy Viet con facilities and fortifications in the Boi Loi Woods.

Intelligence reports indicated that the area of operation contained numerous important enemy base camps which were used for logistical and command purposes. There were indications that one complete Viet Cong battalion and part of another were operating in the area.

Operation Manhattan began on 23 April when the 4th Battalion, 23rd (Mech) Infantry moved to secure Landing Zones (LZ‘s) for the 4th Battalion, 9th Infantry and 2nd Battalion, 14th Infantry. After landing and securing the areas, the units began conductiong local search and destroy operations. That same day the 1st Battalion (Mech) 5th Infantry secured an LZ for the 1st Battalion, 27th Infantry while the 34th ARVN ranger Battalion established a blocking position along the Saigon River. The 3rd Brigade, 4th Infantry Division conducted search and destroy operations southeast of Dau Tieng.

The following day the1st Brigade conducted search and destroy operations in their sector. During the afternoon Company B, 2nd battalion, 14th Infantry received small arms and automatic weapons fire from an unknown number of Viet cong. The fire was returned with small arms, M-79 grenade launchers and artillery. The fierce firefight resulted in one Viet Cong killed, and no US casualties. Later in the evening Company B, 2nd Battalion 14th Infantry came under a mortar attack from an estimated enemy platoon. They countered with small arms, automatic weapons and artillery. The fight lasted about 10 minutes; and one US soldier was wounded. The American counterfire blasted the enemy positions, but Viet Cong losses could not be determined. Late that evening, an ambush patrol from Company A, 4th Battalion, 9th Infantry engaged an unknown number of guerillas. Ina short but heavy firefight, two Viet Cong were killed; there were no US casualties.

On the afternoon of 26 April, company B, 1st Battalion, (Mech) 5th Infantry engaged and killed a Viet Cong sniper who had had been harassing their position. Company C, 2nd Battalion, 27th Infantry conducted two air mobile assaults. Their first landing zone was "cold", but the second time they sat down they came under small arms fire from an unknown number of Viet

Cong. The Infantrymen returned the fire with small arms and automatic weapons killing two Viet cong. All during the day, US units encountered many booby traps and mines. Though they moved cautiously, one soldier was killed and 12 were wounded by the booby traps.

Between 27-30 April, all brigades continued to conduct search and destroy operations in their sectors. On 27 April, company A, 2nd battalion 14th Infantry discovered a largeife weapons cache containing 105 rifles and pistols, 12 machine guns and over 100,000 rounds of ammunition. This cache was located in a complex with many bunkers and tunnels which was believed to be a base camp and supply point for a Viet Cong unit that had been reported operating in that area.

On 28 April 1967, Company C, 2nd Battalion, 14th Infantry positions received small arms, automatic weapons and 82mm mortar fire from an unknown size Viet Cong force. Fire was returned with small arms, automatic weapons and artillery, resulting in one Viet cong being killed. A sweep of the area following the battle revealed a number of blood trails and bandages, indicating that there were additional enemy casualties. There were no casualties among US forces. Early the next morning Company B, 4th battalion, 23rd (Mech) was hit by a large Viet Cong force. The enemy employed small arms, mortars, and rifle grenades in their attack. The infantrymen returned the fire with small arms, automatic weapons, and artillery. As the battle continued, the guerillas fire on the unit with RPG-2 rocket launchers, but only one APC was hit. Close support air strikes were called in, after two hours of intense fighting, the Viet Cong broke contact and withdrew, taking their killed and wounded with them. One US soldier was killed and five were wounded. The only equipment damage was an APC, which was destroyed. Scattered enemy contact by 1st and 2nd Battalion, 27th Infantry and 2nd Battalion, 12th Infantry resulted in four Viet Cong killed and one Viet Cong captured during the period.

During the next five days, all units continued their combat sweeps, with the exception of 4th Battalion, 23rd Infantry who provided security for the engineer jungle clearing operation. On 1 May, Company A, 1st Battalion, 27th Infantry engaged an estimated Viet Cong platoon with small arms and automatic weapons. The short firefight resulted in two Viet Cong killed and no US casualties. The same day Company A, 2nd battalion, 14th Infantry discovered a huge cache containing 35 tons of rice. The rice was evacuated for distribution to Vietnamese refugees. Troops A and D, 3rd Squadron, 4th Cavalry were making sweeps back and forth across the southern edge of the area of operations to spot and engage any Viet Cong who might try to flee that way. They mad three contacts with the enemy during the first week of May, resulting in two Viet Cong killed and five Viet Cong captured. Throughout the Boi Loi Woods, and especially in the southern sector, a great many booby traps and mines were encountered, resulting in numerous US casualties.

During the period 6-10 May, all units continued search and destroy operations in their assigned sectors. The 2nd battalion, 27th Infantry conducted several combat assaults and the 1st battalion, 25th Infantry teamed up with the ARVN River Assault along the Saigon River.

Starting on 11 May 1967, the main focus of attention was directed at the 65th Engineer Battalion jungle clearing operation. Thirty "Rome Plows" hacked away at the dense undergrowth and tangle of trees in the very heart of the Boi Loi Woods. The emphasis of Operation Manhattan now shifted to providing local security for the engineers through local search and destroy missions and ambush patrols. In addition to the jungle clearing, the engineers also tackled the task of improving and upgrading the roads throughout the operational area. This project had a two fold purpose; one , it increased the mobility and cut the reaction time of the US forces, and two, it would be of long term benefit to the local Vietnamese, who use the roads to travel throughout the area, and for transporting their products to market.

Between 16 may and 6 June, 4th Battalion, 23rd Infantry elements continued to provide engineer security and conduct local search and destroy operations. On 22 May, the battalion began a five day operation in which they inserted and extracted Popular Forces Reconnaissance units, and in conjunction with them conducted combined search and destroy operations and night ambush patrols. On 28 May the 4th Battalion, 23rd Infantry relocated with the engineer elements to continue security for base camp, and at 2400 hours, Operation Manhattan was terminated.

During the 45 day operations, 36 medical civic action programs (MEDCAP’s) were conducted, treating a total of 5,433 patients. In addition, 20 short term, high-impact civic action projects were completed. Schools were repaired and refurbished; refugees were given clothing, cooking utensils, and food; Vietnamese Popular forces outposts were constructed; and large quantities of food-stuffs were distributed to Regional and Popular Forces families. At the request of ARVN authorities, 82 refugee families were relocated to Dau Tieng and furnished clothing, shelter, cooking and eating utensils, and commodity support. All civic action, even though initially undertaken to gain population acceptance of US presence, supported the Revolutionary Development Program. A total of 20 miles of road was upgraded by engineers, giving area residents full access to population centers and market outlets. Large areas of jungle were cleared providing local inhabitants with 4,200 acres of additional farm land.

There were 74 Viet cong killed, 19 captured, and three Hoi Chanhs rallied to the GVN; 201 small arms weapons, 18 machine guns, 42 rounds of artillery ammunitions, 671 mortar rounds, 293 mines, 901 grenades and booby traps, 400,543 rounds of small arms ammunition, 168 cluster bomb units, 3,200 blasting caps, 2,300 feet of detonating cord, 1,800 pounds of TNT, and 2,278 pounds of black powder were captured. In addition, US forces confiscated 34 sampans, 400 pounds of clothing, 443 pounds of medical supplies, 250 tons of rice, 5.5 tons of assorted food stuffs, 398 pounds of documents, 12,760 feet of communication wire, 30 pounds of punji stakes, 17 pounds of tools, one telephone, seven protective masks, two plows, 108 bicycles, one oxcart, six generators and six outboard motors. There were 461 huts, 1,594 yards of tunnels, 1,163 bunkers, 421 foxholes, 5,635 yards of fighting trench, seven base camps, one radio, one bicycle repair shop and two small hospitals destroyed.

Operation Manhattan inflicted severe logistical loses interview Cong/NVA forces in terms of food, supplies, ammunition, and weapons captured or destroyed. The large number of base camps, bunkers, and tunnels destroyed also constituted a major setback to enemy forces. The clearing of extensive areas of jungle denied the Viet Cong a safe haven, and seriously reduced the enemies’ capability to conduct offensive or harassing operations in and around the Boi Loi Woods sector.