After Action Report and lessons learned   Operation: Oahu HEADQUARTERS 1ST BATTALION (MECH) 5TH INFANTRY       APO San Francisco 96225 AVDCSBA-C        14 September 1966 SUBJECT: Combat After-Action Report (RCS:  MACV J3-32)   TO: Commanding Officer 1st Brigade 25th Infantry Division ATTN: AVDCFB-C APO U.S. Forces 96225   1. NAME OF OPERATION :  Operation OAHU. 2. DATE OF OPERATION :  140700AUG66 - 312337AUG66. 3.LOCATION : Truong Mit and vicinity (XT 4039), Xom Roc and vicinity (XT 3836), Go Dau Ha and vicinity (XT 3825), Tay Ninh and vicinity (XT 2050), vicinity XT 4243 and vicinity 5617, Tay Ninh and Hau Nghia Provinces, republic of Viet Nam. 4. CONTROL OR COMMAND HEADQUARTERS: 1st Battalion (Mechanized), 5th Infantry attached to the 1st Brigade, 25th Infantry Division. 5. REPORTING OFFICER: LTC Victor F. Diaz. 6. TASK ORGANIZATION: 1st Bn (Mech) (-), 5th Inf, LTC Victor F. Diaz, Commanding Scout Platoon, 1LT J. E. McQuinn Heavy Mortar Platoon, 1LT L. B. Wickman Company A, CPT J. B. Gerard, Commanding Company B, CPT R. G. Vanneman, Commanding Company C, CPT W. A. Blair, Commanding One Squad, Co A, 65th Engr Bn Nine RVN National Policemen. 7. SUPPORTING FORCES : Battery A, 7/11th Artillery: Attached. 8. INTELLIGENCE:  a. Intelligence Prior to Operation. The operational area was known to be VC dominated and the bulk of the indigenous personnel actively supported the VC. Numerous local guerrilla elements were known to operate throughout the general area and had on previous operations employed sniping and mining tactics against friendly elements. The B84 LF Company was reported vic XT 390340 during the later part of July and ARVN sources indicated a VC training school was located at Trang Dau (XT 310450). On 7 Aug 66 it was reported that the road from XT 320475 to XT 368427 was blocked by numerous roadblocks consisting of felled trees. SLAR activity during the period 2-10 Aug was insignificant. b. Enemy Situation During Operation. Initial contact was not made until the second day of the operation, 15 Aug, when Co B apprehended one VCS at XT 330425. The suspect was evacuated to the 1st Bde for interrogation. On the same day Co C conducted a reconnaissance in force and destroyed one 82mm mortar position at XT 329421. While in the area the company received a report that one VC platoon was located at XT 392301 and that ARVN troops had killed three VC but that the platoon was still in the vicinity. The area was checked but no VC were found. While in the vicinity XT 389302 one APC hit an anti-tank mine which rendered minor damage to the vehicle. On the same day the Scout Platoon had one APC hit an antitank mine at XT 371422. The mine was believed to be a 250 pound bomb dud that the VC had installed. The APC was damaged beyond repair. On 16 Aug Co B killed one VC (BC) and captured his Chicom carbine at XT 370378. On the same day five spider holes were destroyed at XT 360364. Also the same day Co C spotted several VC at XT 374345. The company killed one, wounded and captured another VC, one Chicom carbine, documents and small arms ammunition. The same day the Scout Platoon had one APC extensively damaged by an antitank mine at XT 358438. The area had been swept by a mine detector team beforehand which could not detect the mine because it was made of wood and was detonated by a bamboo strip lying in the path of the APC. In that same area the platoon found and destroyed three antitank mines. The first mine at XT 370424 utilized the same type bamboo strip triggering device, was homemade, in a pottery crock, and weighed from 8-12 pounds and used a CBU bomblet for a detonator. The second mine, similar to the first two, was destroyed in the same area; however, it had a normal pressure-type detonating device. One other anti-tank type mine was destroyed at XT 379414. This mine consisted of one 105mm round and one 2.75" rocket, both of which were rigged for detonation by a CBU bomblet. Two VCS were apprehended at XT 379414 and one other at XT 384410. On 17 Aug Co B captured one VCS near a house at XT 380445. Inside the house one Chicom carbine was found. On 19 Aug a roving patrol received sporadic small arms fire from approximately two VC at XT 353462. During the night of 19 Aug a patrol fired on four VC at XT 349423. The VC broke contact leaving behind a Mauser rifle, model 98. Throughout the day of 20 Aug sporadic small arms fire was received and four VCS were apprehended at XT 341458. On 21 Aug, found and destroyed at XT 436353 were one 155mm dud, five Chicom grenades and one 25 pound bomb rigged for command detonation. Ineffective small arms fire was received on 22 Aug from XT 595146. During the afternoon of 23 Aug rewards offers and Chieu Hoi leaflets were air dropped throughout the AO. On the night of 24 Aug a VC battalion was reported to be bivouacked at XT 423440. Heavy artillery fire was placed on the area which was checked on 25 Aug. Found were numerous fresh tracks, cut brush for camouflage and four bicycles, reinforced to carry heavy loads. In a through search of the area Co C captured one VC propaganda booklet; three VC uniforms, black; digging tools and hand drills. Destroyed in the same area were two bunkers and three houses, one of which contained 30 expended cal .30 shell casings and one 250 pound bomb. Five VCS were apprehended fleeing the area. On 26 Aug the battalion destroyed 27 55 gallon drums of CS gas vic XT 379472. The CS containers were later determined to be old US origin. Each drum was rigged with one fuze detonating device. One camouflaged house with 15 firing type foxholes and two bunkers were destroyed in the same area. Co C destroyed one CBU bomblet at XT 371478 then received sporadic small arms fire from XT 374484. In Pursuit of the VC the company destroyed a house hidden in the woods at XT 375480. Inside were seven claymore weapons; 18 fragmentation hand grenades, three of which were booby trapped outside; one German voltmeter; one Czech potato masher type grenade; nine 45 volt batteries; four VC blasting caps; one claymore tripod; three fifty foot rolls of blasting wire and bicycle axles. The house appeared to be a munitions storage area or factory and several spider holes were destroyed around the area.   one VCS was apprehended at XT 359460 and evacuated to the 1st Bde. On 28 Aug one APC hit an antitank mine at XT 336397. The APC was extensively damaged and attested to the fact that very large antitank mines were employed throughout the AO on likely vehicular approaches. On 29 Aug Co C received one incoming RPG-2 round vic XT 355442. The company screened 150 male and 100 female VCS, of which 10 were found to be VCC and 92 were detained for further interrogation. On 30 Aug Co B received sporadic small arms fire from XT 396246. Co A destroyed one antitank mine and one hand grenade in a mound of dirt at XT 540179 on 31 Aug. Co C received small arms fire from XT 565176 and, while checking the area, destroyed four punji pits and apprehended one VCS. c. Terrain and Weather. (1) Climatic Conditions. Adverse weather conditions had minimal effect on the overall operation. Low ceilings on two occasions delayed the use of command and control helicopters during early morning hours. Isolated rain showers also hindered helicopter activity. As a result of  the rain, mechanized movement was often channalized in several areas. It was often necessary to bypass specific wet areas and to take special interest in selecting crossing sites for existing streams. Reconnaissance elements were extensively employed to select specific routes to objectives. (2) Relief and Vegetation. The area of operations had little relief and thus a poor drainage system. The water table is high and much of the area was saturated. The rubber plantation areas were relatively dry and free of dense undergrowth. The major streams in the AO may be crossed but only at a few points during the rainy season. Crossing sites utilized as follows: Tay Ninh - XT 358454, XT 344409, XT 360406. (3) Man-made Obstacles. No extensive fortifications, trenches, or tunnels were encountered in the area. However, all the roads within the operation area were heavily mined. Cultivated fields often restricted mechanized movements. 9. MISSION. 1st Bn (Mech) (-), 5th Inf conducts local search and destroy operations and reconnaissance in force in AO BOBCAT and performs security missions along Hwys 1 and 22, commencing 140700AUG66 as part of the 1st Bde, 25th Inf Div (Incl 1, Operation Overlay). 10.CONCEPT OF OPERATION: The battalion (-) would conduct the operation in five phases: PHASE 1: Battalion (-) moves from base camp (XT 6516) along Hwy 1, Hwy 22, to vic XT 316352, 140700AUG66. PHASE 2: Battalion (-) conducts S&D operations along Axis RED 140700AUG66 and effects link-up with Co B, 1/5th Mech, vic Obj ZULU (Incl 1). PHASE 3: Battalion (-) establishes a base vic XT 354430  and secures pick-up zone vic XT 3543 for helicopter extracation of 4/9th Inf. PHASE 4: Battalion conducts reconnaissance in force, S&D operations in AO BOBCAT (Incl 1). PHASE 5: Battalion returns to base camp on order. 11. EXECUTION: 14 August 1966 During the day the battalion conducted the first three phases of the operation (Incl 1) and prior to 1800 hours the battalion (-) established its base perimeter vic XT 353429. Six ambushes were established during darkness. No contact was made and all returned at first light. Company A : The company maintained a base vic Go Dau Ha (XT 387251). At 0715 hours the company attached one platoon to the 1/27th Inf. The company (-) escorted engineer convoys to and from Cu Chi and secured work parties along Hwy 22. Company B: The company was released from attachment to the 4/9th Inf at 0800 hours, established blocking position ZULU (XT 337437), then secured the 4/9th Inf pick-up zone vic XT 3543. Upon completion of the 4/9th Inf extracation at 1423 hours the company moved to the battalion base and prepared defensive positions. Company C: At 0700 hours the company departed the base camp and moved to conduct S&D operations along Axis RED. The company then linked up with Co B, 1/5th Mech vic Obj ZULU (XT 337437) and made a sweep through the proposed battalion base location. After completion of the sweep the company prepared its defensive positions. Scout Platoon: The platoon departed base camp at 0700 hours moving with the battalion(-) to vic Go Dau Ha, then escorted the battalion trains to the battalion base via Hwy 22 (bypass), which was accomplished by 1120 hours. The platoon then escorted the maintenance recovery team back to Go Dau Ha and returned to the battalion base.   15 August 1966 Throughout the day elements conducted reconnaissance to determine trafficability of stream crossing sites and provided security for artillery elements and engineer work parties (Incl 1). The battalion established five ambushes and two OP/LP's during darkness. No contact was made and all returned at first light. Company A: The company (-) continued its mission of securing the artillery base at Go Dau Ha and engineer work parties along Hwy 1 and Hwy 22. Company B: At 0830 hours the company departed the battalion base to conduct a reconnaissance in force of Obj 21 (XT 336345),  Obj 13 (XT 326354), Obj 15 (XT 318357) and Obj 5 (XT 310380), respectively (Incl 1). One VCS was apprehended vic XT 330425 at 1000 hours. By 1615 hours the company returned to the battalion base without contact. Company C: Departing the battalion base at 0830 hours the company made a reconnaissance of Obj 6 (XT 362326), Obj 18 (XT 368317), Obj 26 (XT 380308), Obj 22 (XT 384357) and Obj 7 (XT 399365), respectively. At 0916 hours one mortar position was found and destroyed vic XT 329421. The position appeared to have been for an 82mm mortar. At 1240 hours a Special Forces Advisor in the area reported that a VC platoon was located vic XT 392301 earlier that morning and that ARVN troops had killed three VC but that the VC platoon was still in the vicinity. The company checked the area but no VC were found and no contact was made. One APC received minor damage from an antitank mine vic XT 389302 at 1316 hours. The vehicle was repaired in place. One VC suspect was apprehended at 1544 hours vic XT 395330. The company completed its search at 1600 hours and returned to the battalion base. Scout Platoon: The platoon departed the battalion base at 0830 hours to check the trafficability of stream crossing sites #2 (XT 358454), #3 (XT 402443) and  #4 (XT 338359). Site #2 was found to be trafficable and two other crossing sites were located vic XT 344409 and XT 360406. At 1150 hours one APC hit an anti-tank mine vic XT 371422. The vehicle was totally destroyed and five WIA's were sustained. 16 August 1966 Through the day elements conducted S&D operations and provided security for artillery elements and for engineer work parties at Go Dau Ha (Incl 2). The Bn established six ambushes and two OP/LP's  during darkness. No contact was made and all returned at first light.   Company A The company (-) continued its mission of providing security for artillery elements and engineer work parties at Go Dau Ha. Company B The company conducted S&D operations along the western portion of Axis GAS to Obj 24 (XT 355345) and Obj 1 (XT 353364) (Incl 2). At 1152 the company killed one VC (BC) and captured his Chicom carbine vic XT 370378. At 1336 hours five spider holes were found and destroyed vic XT 360364. The company completed its S&D operations at 1631 hours and returned to the battalion base. Company C: The company departed the battalion base at 0730 hours to conduct S&D operations to Obj 27 (XT 370345) (Incl 2). At 1241 hours an element found a cargo pack marked "2/22" and one pair of US boots vic XT 277383. Several VC were spotted vic XT 374345 and elements were maneuvered against them. At 1602 hours the company wounded and captured one VC and his Chicom carbine vic XT 374345. Another VC was wounded and captured in the same area at 1608 hours, but no weapon was found. At 1632 hours one of the VC died. The other VC, the Chicom carbine, some documents and small arms ammunition were evacuated to the 1st Bde. The company then returned to the battalion base. Scout Platoon: At 0745 hours the platoon departed the battalion base with all damaged vehicles for Go Dau Ha. While enroute, one of the platoon's APC's hit an antitank mine vic XT 358438 at 0805 hours. Three casualties were sustained, one of which died while awaiting evacuation. The remaining two WIA's were evacuated at 0845. The antitank mine, which was not detected  by the mine detector, was made of wood and detonated by a bamboo strip lying in the path of the APC.  Concussion from the exploding antitank mine detonated three claymore weapons and several CS grenades carried inside the vehicle,  which was extensively damaged. At 1045 hours a large antitank mine with a metal case and the same type bamboo strip triggering device was found and destroyed vic XT 370424. The homemade mine weighed 8 to 12 pounds, was in a pottery crock, and used a CBU bomblet for a detonator. At 1440 hours another antitank mine was found and destroyed in place at XT 372422. This mine, similar to the previous one found, weighed 8 to 12 pounds, was in a pottery crock and also used a CBU bomblet for a detonator. At 1450 hours a third homemade mine was found and destroyed in the area. This one,  like the previous two, was of pottery type but had a normal pressure-type detonating device. At 1725 hours the platoon found and destroyed another mine vic XT 379414. The mine consisted of a 105mm round and a 2.75" rocket, both of which were rigged for detonation by a CBU bomblet. At the same time two VCS were apprehended vic XT 379414 and turned over to GVN authorities vicinity Truong Mit. At 1830 hours another VCS was apprehended vic XT 384410 and evacuated to the 1st Bde S2.     17 August 1966 Throughout the day elements conducted road clearing operations from the battalion base to Go Dau ha, provided security for artillery elements and engineer work parties vicinity Go Dau ha, performed maintenance and conducted daylight patrols in the AO. Five ambushes and one OP/LP were established during darkness. No contact was made and all returned at first light. Company A: The company (-) remained in Go Dau Ha and continued its mission of providing security for artillery elements and engineer work parties. Company B: The company performed maintenance on vehicles, weapons and equipment prior to conducting a platoon size patrol from 1300 to 1800 hours. At 1530 hours the company's patrol captured one VCS near a house vic XT 380445 in which one Chicom carbine was found and returned to the company base at 1800 hours. Company C: Maintenance of weapons, vehicles and equipment was performed during the morning hours. At 1200 hours a platoon patrolled the AO, made no contact and returned to the company base at 1800 hours. Scout Platoon: The platoon continued its road clearing operation to Go Dau Ha and returned at 1345 hours without incident. 18 August 1966 Throughout the day Co's B and C conducted search and destroy operations in the AO. The Scout Platoon was the battalion reaction force and Co A(-) continued its mission of providing security for artillery elements and engineer work parties at Go Dau Ha (Incl 3). During darkness five ambushes, one OP/LP and one ground surveillance (radar) OP were established. No contact was made and all returned at first light. Company B At 0730 hours the company departed the battalion base to conduct S&D operations in Obj 11 (Incl 3) and by 1152 hours the search was completed. The company then searched an area approximately 1000 meters southwest of area 11 (vic XT 335360) for signs of recent enemy activity. This search was completed at 1420 hours with negative findings and the company returned to the battalion base, closing at 1830 hours. Company C: The company departed the battalion base at 0730 hours and conducted S&D operations in Obj 17 (Incl 3).  The search was completed at 1415 hours with negative findings and the company returned to the battalion base, closing at 1505 hours. 19 August 1966 Throughout the day Co A (-) provided security for artillery elements and engineer work parties. The battalion (-) performed maintenance and conducted daylight patrols in the AO. The Scout Platoon remained in the battalion base as the battalion reaction force. The battalion established four ambushes, two listening posts and one ground surveillance (radar) OP during darkness. No contact was made and all returned at first light. Company B: Maintenance of weapons, vehicles and equipment was conducted during the morning hours prior to the conduct of a platoon size daylight patrol in the AO from 1300 to 1800 hours. Finding nothing significant and making no enemy contact the platoon returned to the battalion base, closing at 1800 hours. Company C: During the morning hours the company conducted maintenance of weapons, vehicles and equipment. From 1140 to 1800 hours a platoon size "roving" patrol was dispatched within a 2000 meter radius of the battalion base. At 1500 hours the patrol received small arms fire from an estimated two VC form vic XT 353462. The platoon maneuvered against the fire but all attempts to establish contact were unsuccessful. At 1800 hours the platoon returned to the battalion base camp. Scout Platoon: During the night of 19 Aug 66 the platoon established one ambush vic XT 349423. While enroute to its position, they sighted four VC whom they fired upon. Before continuing to their ambush location they checked the area and found one Mauser, model 98. 20 August 1966 Throughout the day Co A (-) provided security for artillery elements and engineer work parties vic Go Dau Ha. The battalion (-) performed maintenance prior to conducting search and destroy operations in the AO in conjunction with RF and PF forces from 1130 to 1800 hours (Incl 4). During darkness five ambushes, two LP's and one ground surveillance (radar) OP were established. None made contact and all returned prior to 1000 hours. Company B: During the morning hours the company conducted maintenance. At 1100 hours one platoon replaced the Co A platoon attached to the 1/27th Inf. At 1130 hours the company commenced S&D operations in conjunction with RF and PF forces along the southeastern portion of the AO (Incl 4). At 1429 hours an element of the company found three bicycles and the corpse of a female, killed by a gunshot wound in the head, vic XT 370430. The woman was later identified as a  resident of Truong Mit and her body was moved to that village. At 1800 hours the company returned to the battalion base. Company C: One LP established during darkness made contact with two VC at 0120 hours vic XT 360426. The VC were fired upon with small arms and an M79; the VC returned six or seven rounds of small arms fire, then broke contact, fleeing to the north. During the morning hours the company conducted maintenance prior to conducting S&D operations and occupying position X-RAY (Incl 4). At 1130 hours the company fired on six VC running to their front vic XT 370437. The VC dispersed and the company was unable to regain contact. While in the area, the company found a wounded Vietnamese who claimed to be an ARVN soldier captured by the VC. He was given medical attention and evacuated to Tay Ninh. An element received small arms fire at 1258 hours from vic XT 408432. Mortar and small arms fires were returned but results could not be determined. At 1147 hours a sick civilian was found vic XT 409437. He received medical treatment and was also evacuated to Tay Ninh. One WIA, suffering from a leg wound, was sustained as an apparent result of a ricochet. The casualty was treated and remained with the company. At 1715 hours the company closed into the battalion base. Scout Platoon: The platoon conducted maintenance during the morning hours prior to assisting in the afternoon's S&D operations by occupying blocking position ZULU (Incl 4). The operation commenced at 1200 hours and ceased at 1715 hours with the platoon closing into the battalion base with four VC suspects who were apprehended at the blocking position. 21 August 1966 Throughout the day the battalion (-) performed maintenance, conducted a switch of Co B and Co A and cleared routes from XT 361435 southeast to Truong Mit, Bao Don to XT 452289 and southwest to Go Dau Ha. Three ambushes and two LP's were established during darkness. None made contact and all returned at first light. Company A: During the morning hours the company continued its mission of providing security for artillery elements at Go Dau Ha. During the afternoon hours the company was relieved by Co B. Upon the assumption of its mission by Co B, Co A departed Go Dau Ha and moved to the battalion base. Company B: At 0700 hours the company dispatched one platoon to clear routes from XT 361345 southeast to Truong Mit, Bao Don to XT 452289 and southwest to Go Dau Ha. At 1310 hours the remainder of the company departed the area. Found and destroyed at 1355 hours vic XT 436353 were one 155m dud, five Chicom grenades and a 25 pound bomb rigged for command detonation. The company then established its base vic Go Dau Ha. Company C: Throughout the day the company remained vicinity the battalion base and performed maintenance. Scout Platoon: The Scout Platoon, with the Security Platoon attached, established outposts along the route cleared by Co B and secured the road. At 1700 hours the platoon returned to the battalion base. 22 August 1966 Throughout the day elements provided secuity for convoys between Cu Chi and Tay Ninh. The battalion established five ambushes during darkness. None made contact and all returned at first light. Company A: The company departed the battalion base at 0630 hours with the mission of securing the road from the SP (Cu Chi) to check point #4 (Go Dau Ha), inclusive, NLT 0900 hours. At 0840 hours several ineffective small arms rounds were received from vic XT 595146. The element continued movement and were in position at 0850 hours. The company remained in position until all convoys had cleared the area, then returned to the battalion base. Company B: The company performed its mission of securing artillery elements at Go Dau Ha. At 0700 hours elements were dispatched to secure check point #5 (XT 386252), inclusive. The areas were secured and all convoys were moved as scheduled. After all convoys had cleared, the elements returned to the company base. Company C: At 0742 hours the company departed the battalion base with the mission of securing the road from check point #7 to the RP (Tay Ninh) NLT 1000 hours. All elements were in position and remained until 1700 hours, then departed for the battalion base. Scout Platoon: The platoon escorted the convoys from Cu Chi to Tay Ninh, commencing at 0930 hours. At 1105 hours one vehicle turned over vic XT 386254; no damage was done to the vehicle and no casualties were sustained. Two more vehicles had accidents at 1217 hours vic XT 347336. The vehicles were slightly damaged and two minor casualties were sustained. The vehicles were towed to Tay Ninh and the casualties were treated and returned to duty. The platoon then returned the empty vehicles to Go Dau Ha and then returned to the battalion base. 23 August 1966  Co A, Co C and the Scout Platoon remained in the battalion base and performed maintenance. The battalion established two ambushes and five OP/LP's during darkness. None made contact and all returned at first light. Company B: The company (-) continued to provide security for artillery elements at Go Dau Ha and dispatched one element to Tay Ninh at 0725 hours which escorted an artillery convoy to Cu Chi. The escort closed into Cu Chi at 1315 hours without incident. The elements then departed Cu Chi at 1500 hours and returned to the company base at Go Dau Ha. Psy Ops: During the evening hours the Bn S2 air-dropped weapons rewards leaflets and Chieu Hoi leaflets in the following areas: XT 405440, XT 375475, Truong Mit (XT 3940), XT 3635, XT 3434, XT 325345 and XT 310354. 24 August 1966 During the day Co A was attached to the 3/4 Cav to provide security for convoys along the highway from Cu Chi to Tay Ninh. Co B continued its mission of securing artillery elements at Go Dau Ha. Co C and the battalion (-) remained in the battalion base and conducted maintenance of vehicles and equipment. Three ambushes and five listening posts were established during darkness. None made contact and all returned at first light. 25 August 1966 Co A remained in the battalion base and conducted maintenance. The company had a  "be prepared" mission as a reaction force for Co C's operation. Co B(-) continued its mission of securing artillery elements at Go Dau ha. At 0700 hours the company attached one platoon to the 1/27th Inf at Trang Bang. Two ambushes were established during darkness. Neither made contact and both returned at first light. Company C: the company, with the Scout Platoon attached, departed the battalion base at 0655 hours enroute to make a reconnaissance in force vic Obj 1 (XT 417436), Obj 2 (XT 422444), Obj 3 (XT 427453) and Obj 4 (XT 415451). Found on a trail vic XT 420440 was a sign which read: "DANGER -- NO THOROUGHFARE---NO CIVILIANS BEYOND THIS POINT," written in Vietnamese. The company also checked the area vic XT 423440 where H&I fires were placed on a reported VC battalion on 242130AUG66. Found in the area were several fresh tracks, cut brush for camouflage and four bicycles which were reinforced to carry heavy loads. The bicycles were destroyed. At 0945 hours a house with a bunker was found vic XT 423440. Inside the bunker were one VC propaganda booklet; three VC uniforms, black, cut like khakis; digging tools and enough food for ten to twelve people. At 0955 hours the Scout Platoon apprehended two VCS who were fleeing the area on bicycles vic XT 423441. At 1000 hours the company found a house built on stilts over a stream vic XT 422439 with a large washing area around it and scrub brushes on the ground. The house could hold approximately 40 people. In a further search, hand drills, tools and digging equipment were found. Three VCS were apprehended in the same area at 1005 hours. The elements destroyed a house vic XT 426448 which contained 30 rounds cal .30 ammunition (expended). While in the area, the company destroyed three houses, one bunker and one 250 pound bomb vic XT 423450. 26 August 1966 Throughout the day the battalion (-) conducted S&D operations and provided security for artillery elements at Go Dau Ha. Three ambushes and four OP/LP's were established during darkness. None made contact and all returned at first light. Company A: The company departed the battalion base at 0732 to conduct S&D operations in Obj STAR (XT 379478). While enroute, the company found two 55 gallon drums of CS gas vic XT 375475 and at 1015 hours two more 55 gallon drums of CS gas were also found. While searching vic XT 379482, the company destroyed one camouflaged house, 15 firing type foxholes and two bunkers. The company then destroyed all containers of CS gas and returned to the battalion base, (Incl 5). Company B: The company (-) remained at Go Dau ha providing secuity for artillery elements and engineer work parties. During the afternoon hours one platoon escorted an engineer convoy to Cu Chi. One platoon remained attached to the 1/27th Inf at Trang Bang. Company C: The company departed the battalion base at 0735 hours and moved to Obj STRIPE (XT 373480). At 0910 hours one CBU bomb was destroyed vic XT 371478. Several rounds of SA fire were received from XT 374484 and fire was returned. Found and destroyed in a house hidden in the woods vic XT 375480 were seven claymore weapons, 18 fragmentation hand grenades,  three of which were boobytrapped outside, one German voltmeter, one Czech potato masher type grenade, nine 45 volt batteries, four VC blasting caps, one claymore tripod, three fifty foot rolls of blasting wire and three bicycle axles. At 1130 hours two 55 gal drums of  CS gas were found vic XT 373481. The company completed its search and destroyed the CS gas and all enemy munitions then returned to the battalion base. Scout Platoon: The platoon departed at 0630 hours enroute to establish a blocking  position vic XT 365484; however, the platoon was diverted enroute and screened the east flank of the objective area. At 0855 hours one VC suspect was apprehended vic XT 359460. The platoon found and destroyed 21 55 gallon drums of CS gas vic XT 379472, then returned to the battalion base. 27 August 1966 Throughout the day Co's A and C and the Scout Platoon remained in the battalion base to perform maintenance. From 1200 to 1800 hours Co C dispatched a reinforced rifle squad to conduct a reconnaissance of the area vic XT 367427 and XT 369430. The recon was made but nothing was found. The element then returned to the battalion base. Co B (-)  remained at Go Dau Ha providing security for artillery elements. The company attached two platoons to the 1/27th Inf and one platoon provided security for Engr elements between Cu Chi and Go Dau Ha. During darkness three ambushes and six OP/LP's were established. None made contact and all returned by first light. 28 August 1966 Throughout the day elements conducted S&D operations and provided security for artillery elements at Go Dau Ha. Two ambushes and five OP/LP's were established during darkness. No contact was made and all returned at first light. Company A: The company conducted S&D operations vic XT 3935, XT 3936 and XT 3937. Arriving on the objective at 0900 hours, the company made a thorough search and, finding nothing by 1315 hours, the company made a return sweep through the objective and then returned to the battalion base. Company B continued its mission of securing the artillery element at Go Dau Ha. Company C: The company conducted S&D operations  vic XT 3935, XT 3936 and XT 3937. The operation was completed at 1315 hours and, finding nothing, the company returned to battalion base. While enroute, one APC hit an antitank mine at 1510 hours vic XT 336397. Two minor WIA were sustained and the vehicle, damaged extensively, was towed to battalion base. Scout Platoon: The platoon performed a reconnaissance vic XT 347447. Nothing was found and the platoon returned to the battalion base. 29 August 1966 Throughout the day the battalion (-) conducted S&D operations and Co B (-) provided secuity for artillery elements at Go Dau Ha. Co A was attached to the 2/14th Inf at 1200 hours. Six OP/LP's were established during darkness. No contact was made and all returned at first light. Company C: The company, with the Scout Platoon attached, conducted S&D operations vic XT 355442. At 1143 hours six WIA were sustained from an incoming RPG-2 round. One was treated and returned to duty and five were evacuated. While in the area, the elements screened 150 males and 100 females, of which six confessed to being VC and 96 were detained as suspects. The company sustained another WIA when a VC suspect tried to escape a block and was fired on. The round accidentally hit a US soldier in the back vic XT 343454. At 1605 hours all VC and VCS were evacuated to Tay Ninh and the units returned to the battalion base. 30 August 1966 Co A remained attached to the 2/14th Inf vic Tay Ninh. Company B (-) remained at Go Dau Ha securing artillery elements. At 0105 hours one casualty was sustained when a bunker fell in, breaking his leg and injuring his head and one hand. During the day one platoon escorted convoys between Cu Chi and Go Dau Ha. Co C attached one platoon to Co B effective 300900AUG66. The battalion (-) then displaced and returned to base camp. While enroute, the elements received approximately 11 rounds of small arms fire from XT 396246. The fire was ineffective and was not returned due to civilians in the area. The battalion (-) closed into base camp at 1600 hours. At the same time this headquarters received the report that of the VC and VCS turned in on 29 Aug 66  10 were confirmed VC and 92 were being held for further questioning. 31 August 1966 During the day elements of the Bn cleared and secured the road for convoys moving from Tay Ninh to Cu Chi and made a sweep through XT 565176 for a reported two VC companies. Company A: The company was released from attachment to the 2/14th Inf  at Tay Ninh at 0630 hours, then moved to clear and secure the road from Tay Ninh to XT 316356. By 0830 hours the route was cleared and secured and when all convoys had cleared the company returned to base camp, closing at 1310 hours. Company B: The company remained at Go Dau Ha and dispatched elements to secure the road from Go Dau Ha to XT 316356. The mission was accomplished and when all convoys had cleared the company returned to base camp, closing at 1337 hours. Company C: The company departed the base camp at 0700 hours to clear and secure the road from Cu Chi to Go Dau Ha. The company remained in position until all convoys had cleared, then made a sweep through XT 565176 in search of a reported two VC companies. During its sweep, the company received five ineffective small arms rounds at 1330 hours. A thorough search revealed no VC units but four punji pits were destroyed at XT 564184 and one VCS was apprehended at XT 565176. The company closed into base camp at 2337  ending Operation OAHU. 12. RESULTS. a. Friendly Losses: Incl 6, Casualty List. b Enemy Losses: (1) Killed 2 VC (BC). (2) Captured: 10 VC; 108 VCS; 3 Chicom carbines; 1 Mauser, model 98; 1 pair US GI boots;  3 VC uniforms; 1 VC propaganda booklet; Miscellaneous small arms ammo; Miscellaneous documents; Miscellaneous tools; Several hand drills. (3) Destroyed: 5 antitank mines; 1 155mm dud; 1 25 lb bomb (rigged for command detonation); 5 Chicom grenades; 1 250 lb bomb; 7 claymores; 4 punji pits; 19 hand grenades, fragmentation; 1 CBU bomb; 30 cal .30 expended cartridges; 4 houses; 3 bunkers; 15 foxholes; 1 Czech potato masher grenade; 4 bicycles; 3 bicycle axles; 9 45 volt batteries; 4 VC blasting caps; 3 rolls of blasting wire, 50 feet each; 3 claymore tripods; 27 55 gallon drums of CS gas; 1 cargo pack marked "2/22". 13. ADMINISTRATIVE MATTERS. a. The bulk of the resupply was accomplished by  CH-47 helicopters flying from base camp to the forward CP area and by convoy to Go Dau Ha resupplying a company there, supplemented by small tonnages carried on C&C ships. b. Major difficulties were experienced with air resupply operations in that the aircraft continuously reported late. Furthermore, the CH-47 helicopter, while being suitable for transporting bulk items, could not provide the resupply flexibility so vital to a mechanized battalion's combat operations. Airlift sorties were assigned strigently and were on a rigid schedule favoring the supporting aviation element instead of the supported unit. There were several instances in which a helicopter was diverted to another unit temporarily and on one day several sorties were canceled, thereby creating a supply deficiency. There were several helicopter breakdowns, necessitating immediate repair or replacement of the aircraft. The time required for their subsequent replacement delayed resupply efforts considerably. Another problem encountered concerned the inconsistency of loading plans. Each helicopter crew had its own rigid on-loading and off-loading procedure which they would not deviate from, thereby causing a delay in resupply activities due to the necessity of adjusting daily to a new system. The failure of a steel net and a sling harness during flight caused the droppage of 165 gallons of Pol on 19 Aug and various supplies, including a .50 cal weapon, ammunition and an M113 power plant on 20 Aug 66. The advantages of the Chinook aircraft in an operation such as this which is characterized by a static forward resupply area cannot be overlooked, particularly if the above listed deficiencies are corrected. However, the utilization of two UH1D helicopters in lieu of the Chinook would be a better formula for accomplishing the unit mission in that it would provide the essential resupply efficiency and flexibility vital to the nature of this battalion's operations. (1) During the operation, 88 sorties delivered the following supplies: (a) Class I: 48,480 lbs. (b) Class II: 13,135 lbs. (c) Class III: 52,320 lbs. (d) Class IV: None. (e) Class V: 71,605 lbs. (f) Personnel: 41,490 lbs. (g) Miscellaneous: 1. Water: 272,200 lbs. 2. Ice: 35,900 lbs. 3. Parts: 16,460 lbs. (2) The battalion expended the following ammunition and demolitions during the operation: (a) Ctg, 5.56mm, ball  3600 rounds (b) Ctg, 5.56mm, tracer 60 rounds (c) Ctg, 7.62mm, ball  1260 rounds (d) Ctg, 7.62mm, tracer 6400 rounds (e) Ctg, .45 cal, ball  300 rounds (f) Ctg, .50 cal, ball/tracer 4400 rounds (g) Ctg, 40mm, grenade, HE 432 rounds (h) Ctg, 81mm, HE  1184 rounds (i) Ctg, 4.2", HE  88 rounds (j) Ctg, 4.2", illumination 4 rounds (k) Ctg, 4.2", smoke, WP 194 rounds (l) Grenade, hand, fragmentation  91 each (m) Rocket, M66, heat (LAW)  30 each (n) Mine, AP, M18  48 each (o) Signal, illumination, ground, green   36 each (p) Signal, illumination, white cluster     36 each (q) Flare, surface, trip, M49 192 each (r) Charge, demo, block, comp C 144 pounds (s) Caps, blasting, non-electrical 20 each (t) Charge, demo, shaped, 15 lbs 9 each (u) Firing device, demo 200 each (v) Fuze, blasting, time 100 each (w) Ignitor, blasting, fuze 150 each (x) Grenade, hand, smoke, green 48 each (y) Grenade, hand, smoke, yellow 16 each (z) Grenade, hand, smoke, red 32 each (aa) Grenade, hand, smoke, violet 160 each (bb) Grenade, hand, smoke, HC 64 each (cc) Ctg, 105mm, HE/WP 2200 rounds c. Maintenance: The battalion initiated the operation short one (1) M106 from the Mortar Platoon and one (1) M113 APC from Co A. (In addition, the battalion was short one (1) M578 VTR which had never been issued.) During the operation, four (4) M113 APC's were damaged by antitank mines. Of these, one (1) was so severely damaged that it was destroyed in place. The remaining two (2) were towed back to base camp where they were declared uneconomically repairable. The locations of the mines were as follows: XT371422, XT 360434, XT 335397 and XT 372424. There were fifty-five (55) tracks that were rendered inoperable due to mechanical failure. Of these, thirty-four (34) were repaired in the field and continued the operation while the remaining twenty-one (21) were evacuated to base camp for repairs. Eleven (11) of these vehicles were repaired and returned to the battalion before the termination of the operation. Of the remaining ten (10) M113's that were not returned to field operations, four (4) were declared uneconomically repairable, three (3) have been turned into Support Maintenance to determine whether they are economically repairable and the remaining three (3) are in the process of being repaired by this unit. The major mechanical failure experienced was the separation of the spindle and its inserts from the hull of the carrier. There were twelve (12) of these failures and all twelve had to be evacuated. To date, two (2) of these vehicles have been repaired. The majority of the mechanical failures, however, had to do with the power plant and were repaired by this unit without major difficulty. d. Treatment of Casualties, Evacuation and Hospitalization:  A total of 167 patients were seen in the battalion forward aid station during the operation. Of these 167 patients, 141 had disease, 8 were injured as a result of hostile action and 18 received non-battle injuries. Ten of the diseased and two of the injured patients were evacuated. Most of the serious casualties bypassed the forward aid station and were evacuated directly to areas providing definitive care. e. Communications. (1) During Operation OAHU, 140700AUG66 thru 312337AUG66, this unit employed FM radio, AM radio, VHF radio and tactical wire. The primary means of communications with subordinate units (during the daylight hours) was FM radio. Wire communications were used in the CP complex and when the companies were in defensive postures at night. During this time, FM radio nets reverted to listening silence. The battalion maintained FM, VHF and RATT communications with brigade headquarters. Wire communications were not maintained with brigade due to the distance involved. Air messengers were used daily when aircraft were available. (2) VHF communications enabled this unit to maintain voice contact with both brigade and division headquarters. The attachment of an AN/MRC 34.5 to the mechanized battalion enables the unit to process voice traffic expeditiously and should be attached during extended operations when tactically feasible. 14.SPECIAL EQUIPMENT AND TECHNIQUES:  None. 15. COMMANDER'S ANALYSIS. a. Fragmentating a mechanized battalion reduces its firepower and shock action and seriously hampers its flexibility. b. Employing a mechanized unit in a static security role, ie., securing an artillery battery, protecting engineer work crews, ect., fails to make use of the mobility and shock action which characterize mechanized infantry. c. The CH-47 helicopter is an excellent resupply vehicle where tonnages are to be moved at a fairly predictable rate. It is only marginally satisfactory for resupply of a mechanized infantry battalion on operations. When so employed it must be supplemented by a number of sorties of a lighter ship which permits greater flexibility in making up to the minute adjustments in the composition of the loads. FOR THE COMMANDER:   6 Incl       JAMES G. ANDRESS   as       CPT,                     INF Adjutant DISTRIBUTION:  Special   CASUALTIES SUSTAINED -- OPERATION OAHU NAME  RANK UNIT DISPOSITION HARRIS, Steve PFC E-3 HHC DOW RAMOS-DELIZ, Luis  SP5 E-5 HHC WIA MCDOUGLE, Terry PFC E-3 HHC WIA CHANDLER, Roger  SP4 E-4  HHC  WIA GROOMS, Hughson PFC E-3 HHC WIA WOODS, Richard SGT E-5 HHC WIA SCHMID, Robert  SP4  E-4 HHC KIA PRETTYMAN, Kenneth SP4  E-4 HHC WIA DEVEREAUX, Patrick SP4  E-4 Co C WIA JEDLOWSKI, Steven  SP4  E-4 Co C WIA CURLEY, Patrick SP4  E-4 Co C  WIA DOUGLAS, Roland  2LT Co C WIA STARNES, Milburn  SGT E-5  Co C WIA PHILLIPS, David SP4  E-4 Co C WIA HAUN, Henry  SGT E-5 Co C WIA NORRIS, Kibby PFC E-3 Co C  WIA JONES, Van PFC E-3  Co C WIA DALE, David  SP4 E-4 Co C WIA NUTT, Andrew PFC E-3 Co C  WIA NELSON, Errol  PVT E-1 Co C  WIA Inclosure 6 (Casualty List) to Ltr, HQ, 1st Bn (Mech) 5th Inf, subj Combat Operations After-Action Report (RCS:  MACV J3-32), dtd 14 Sep 66. BACK