Operation Desoto


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Operation Desoto originated from the joint Vietnamese-U.S. 1967 Combined Campaign Plan in which III MAF forces were to relieve ARVN units from outpost duty so that they could be employed more effectively elsewhere in the Revolutionary Development Program. The 4th Battalion, 4th Regiment, 2d ARVN Division, stationed in Duc Pho District, was one of the units selected to concentrate on the pacification program. In turn, General Stiles' Task Force X-Ray assigned one of its battalions to relieve the ARVN battalion. Lieutenant Colonel Raymond J. O'Leary's 3d Battalion, 7th Marines received this mission.
The relief operation termed Desoto began on 27 January. Marine helicopters lifted Company L and four 105mm howitzers and crews of Battery I, 11th Marines to Nui Dang to relieve the Vietnamese units there. The howitzers were to provide fire support for a battalion assault the next morning. At 0800 on the 28th, Company M, followed by the rest of the battalion, made a helicopter assault into landing zones just north of the Nui Dang position. The only op position was sniper fire, but intermittent firing continued throughout the day.
Shortly after the battalion's landing, Companies I and M moved out to secure the villages of Vinh Binh and Truong Sanh.   Sniper fire harried Company I during its advance to Vinh Binh, but by the end of the day the company had secured the village and established night positions east of it. Company M also encountered light harassing fire as it moved toward Truong Sanh, but it occupied the village without opposition. Villagers at Truong Sanh told the Marines that strong VC forces were east of the Song Quan (Quan River) in the hamlet of Tan Tu
To exploit this information, the battalion command group, Company M, and one platoon moved east of the stream south of the hamlet. As the lead elements began to move into Tan Tu they came under sniper fire, and when they tried to close with the snipers a strong VC bunker complex stopped their advance. The company called in artillery and air strikes against the positions. After the bombardment, the Marines attacked again, but stopped once more because of heavy fire from machine guns and automatic weapons to the north and northeast. The Marines directed more supporting arms fire against the Communist positions. Under its cover, Company M recovered its dead and wounded and, following orders from the battalion, withdrew across the stream and established company night positions.
Because of the sharp engagement east of the Song Quan, Lieutenant Colonel O'Leary decided to use both Companies I and M to assault the Tan Tu village complex on the 29th. During the night sup porting arms blanketed the village to prepare for the attack, and at first light both companies began moving toward the objective. As they forded the Song Quan, sniper fire broke out. The enemy snipers were unusually accurate; they wounded three men from Company I almost immediately. Both companies returned the enemy fire and pushed on into the village against little resistance.
By 1330, the Marines had secured Tan Tu and moved into the adjacent village of Sa Binh, still harassed by long-range sniper fire. Periodic bursts of heavy fire were the only sign of the enemy; the majority had withdrawn. The two companies searched the village and dug in for the night on a small knoll north of Sa Binh.
The next day, Company M again searched the two communities. One patrol found an enemy- land- mine foundry with 500 pounds of uncut metal, mine molds, and tools. After photographing the entire works for intelligence purposes, the Marines demolished the foundry.
Meanwhile, Company I had started to sweep southeast toward the village of Hai Mon. Since this area had sheltered enemy snipers on the 29th, the Marines first called in artillery and naval preparatory fires on suspected positions near the community. As the lead element advanced, they met heavy small arms fire from Hai Mon. The FAC assigned to Company I called in jets armed with napalm and 500-pound bombs, followed by attacks by two UH lEs which hit the area with rockets and machine gun fire. One UH-1E, badly damaged by ground fire, force-landed at the battalion CP.
One of the battalion's 106mm recoilless rifles revealed the degree of fortification of the village when one of its rounds hit one of the thatched huts and revealed an oval concrete bunker. A direct hit from another 106mm round penetrated the bunker.
Hai Mon proved to be more difficult by the minute. The defending enemy had fortified many rice paddy dikes to create positions providing a deadly cross-fire. By 1330, Company I had taken cover in deep rice paddies west of the village. As the after noon wore on, the situation became even worse. Enemy gunfire, including fire from heavy machine guns, raked the company from four sides. The company could not evacuate its casualties and ammunition ran low. At 1655, the battalion ordered Company I to break contact and withdraw to the west.
Withdrawal and reconsolidation were not easy. Company M fought its way up to the eastern flank of Company I and replenished the latter's ammunition, then both companies tried to disengage under the cover of air strikes, artillery, and naval gunfire. By 2000, Company M had established a casualty collection point and both companies gathered their casualties there. The Marines could not complete the medical evacuation until 2200 because some casualties had been point men caught in the open by the initial enemy fire. Marines could recover these bodies only by crawling out under cover of darkness. By then, the battalion estimated that Hai Mon was 60 percent destroyed. Supporting arms amounting to 325 5-inch naval rockets, 125 5-inch shells, 590 105mm rounds, and 50 tons of aviation ordnance had smashed the enemy fortifications.
Lieutenant Colonel O'Leary, realizing the village was highly fortified, was not content with the damage to Hai Mon and ordered more shelling to neutralize the area. Again on the 31st, the battalion directed air, naval gunfire, and artillery at all known and suspected Communist positions in and around the village.
While supporting arms pounded Hai Mon, Company M resumed the deliberate search of the Tan Tu hamlets, as Company I swept the area west of Hai Mon. To the south, Company K, operating from Nui Dau, made several small contacts, but enemy activity was light. The heaviest action of the day occurred at 2200 when the battalion command post and logistic support area came under small arms and 60mm mortar fire. Shortly thereafter, 20 VC probed the perimeter. Company L and Headquarters and Service Company security troops stopped the attack in the outer wire of their defenses, killing two of the enemy. Marine losses were 14 wounded, eight of whom required evacuation. The battalion's 81mm mortars and supporting artillery fired on possible. escape routes to catch the withdrawing enemy, but a follow-up search of the area turned up only two Russian-made rifles, several grenades, and some satchel charges.
During early February, the battalion remained in the new TAOR and conducted repeated search and destroy operations. On 2 February, Lieutenant Colonel Edward J. Bronars relieved Lieutenant Colonel O'Leary as commanding officer of the battalion. The next day, 3 February, Companies L and M, 5th Marines, which joined the operation on 31 January, conducted a two-day sweep in the village complex southeast of Nui Dang. Although contact in the area was light, the Marines found the hamlets to be well fortified, and discovered more than 100 tons of rice which they bagged and turned over to ARVN authorities. After searching this community, the Marines again turned their attention to Hai Mon and Hill 26 east of it.
Aerial observation reports and Company I's bloody experience of the 30th indicated that most of the enemy fortifications in the village pointed west. Lieutenant Colonel Bronars decided to attack the position from the east by vertical envelopment, using Companies L and M. The morning of S February, artillery, naval gunfire, and air bombardment blanketed the objective area. The assault helicopters from Lieutenant Colonel Ural W. Shadrick's HMM-262 followed approach and retirement lanes which allowed the artillery at Nui Dang and the naval guns offshore to maintain suppressive fire throughout the landing.
Light machine gun fire and several rounds of 57mm recoilless rifle fire greeted the companies as they moved into the hamlets. They responded by calling in artillery and naval gunfire. At this time, Marines spotted a number of sampans carrying about 30 Viet Cong fleeing northward across the Song Tra Cau. Bronar's Company M sprayed the withdrawing force with small arms fire and fixed-wing aircraft made several strikes, destroying several of the sampans.
After seizing Hill 26 and Hai Mon, the Marines searched the area and uncovered a vast, intricate bunker and cave system. They promptly destroyed the bunkers, but the caves, particularly those on Hill 26, were so extensive that the battalion called in engineers to determine the amount of explosives needed to seal them. By the time the last cave on the hill had collapsed, the engineers had used 3,600 pounds of explosives. The well-prepared defensive positions and the skillfully laid fields of fire confirm ed that the Communists had expected an attack from the west; the assault from the east caught them by surprise. Possession of the village enabled the Marines to control the southern bank of the Song Tra Cau inlet.
Desoto continued during February, consisting of frequent platoon and company sweeps and extensive patrolling and ambushing throughout the area. The battalion's area of operations expanded with each passing day. The villages of Thuy Trieu, An Trung, Dong Quang, Vinh Lac, and Thanh Lam appeared on daily situation reports, but for the Marines on the ground each one was just another "ville" that had to be seized and cleared, a dirty and often painful task.  Attrition among company grade officers was quite high, and the high tempo of daily operations had a noticeable deleterious effect on the rifle companies.
Snipers were a constant threat and the major source of Marine casualties. The Marines countered with scout-sniper teams positioned at carefully selected vantage points; however, the teams had difficulty in locating an enemy who fired from cleverly constructed spider traps
Throughout the month the battalion exploited reports of Viet Cong positions with artillery and naval gunfire and extensively used radar-controlled aerial bombing of suspected enemy concentrations. Surveillance reports indicated that the supporting arms attacks were very effective against the Communist sanctuaries.

Deckhouse/Desoto
While Lieutenant Colonel Bronars' battalion gradually expanded control of the Nui Dang-Nui Dau area, the Marines of Colonel Harry D. Wortman s SLF landed near Sa Huynh at the southern tip of the district. The SLF's amphibious operation area included the only area in I Corps where the Annamite Mountains extend to the coastline. It was a predominantly Communist-controlled area. The heavily forested hills concealed the supply routes leading to major enemy base areas further inland. A sheltered harbor and anchorage, and several landing beaches on the coast enhanced Sa Huynh's infiltration potential.
SLF Operation Deckhouse VI had several goals: to prevent free movement of Communist forces in the area; to conduct harbor, beach, and airfield surveys to locate a site from which to provide more economical logistic support for allied forces in southern Quang Ngai; and to provide security for the construction of a CIDG camp which would establish permanent government control in the region. Upon completion of these tasks, the SLF was to join with Bronar's battalion to continue search and destroy operations throughout the Duc Pho region.
The first phase of the operation began at 0800 16 February when the naval gunfire support ships, including the rocket ships USS Clarion River (LSMR 409) and USS White River (LSMR 536), began preparation fires. When the naval fires ended, two UH- lEs of VMO-2 directed air strikes on the primary and alternate landing zones: At 0855, the first wave of helicopters from Lieutenant Colonel Kenneth E. Huntington's HMM-363 lifted off the deck of the USS Iwo Jima (LPH-2) with Company A of Lieu tenant Colonel Jack Westerman's 1st Battalion, 4th Marines. The helicopters landed on high ground five miles inland. Two UH- lE gunships accompanying the flight suppressed a platoon-size ambush, killing 12 of an estimated 30-man VC force near the LZ.
On 20 February, operational control of the SLF passed to General Stiles' Task Force X-Ray. Lack of opposition around Sa Huynh allowed General Stiles to reorient the BLT's efforts. He ordered Westerman to begin deliberate search and destroy operations to the northeast, while elements involved in Operation Desoto moved into blocking positions south and west of Nui Dau. By the afternoon of the 25th, the BLT had passed through Lieutenant Colonel Bronars' battalion and moved into positions near Nui Dau, thus ending the first phase of Operation Deckhouse VI.
During their sweep north, Lieutenant Colonel Westerman's Marines found numerous bunkers, tunnels, caves, and supply caches; they demolish ed 167 fortifications, captured 20 tons of supplies, and destroyed 10 caves and 84 booby traps. In the process of defending these positions, the enemy force killed six Marines and wounded another 61. Most of the enemy casualties came from supporting arms fire called in by reconnaissance teams operating to the west; these fires killed 201 enemy soldiers.
The operation plan scheduled the second phase of Deckhouse VI to take place along the northern por
tion of the Desoto TAOR. Intelligence reports in dicated that the 38th VC Battalion was infiltrating into the Duc Pho area from the northwest. General Stiles arranged to exploit this information by an operation involving his Task Force X-Ray, the SLF, and 2d ARVN Division units in Quang Ngai Province.
One Marine and two ARVN battalions were to be helilifted into the area northwest of Duc Pho and sweep eastward. At the same time, other 2d ARVN Division units would screen the northern flank of the operational area while elements of the 3d Battalion, 7th Marines secured the southern flank from block ing positions within its TAOR. The plan ordered the SLF Marines to make an amphibious assault between the Mo Duc-Duc Pho district boundary and the Song Tra Cau, then sweep southwest to entrap any VC withdrawing from the other allied forces advancing eastward.
On the morning of 26 February, Lieutenant Colonel Peter L. Hilgartner's 1st Battalion, 5th Marines and two ARVN battalions landed northwest of Duc Pho and began sweeping northeast. They en countered only long-range sniper fire, but discovered numerous caves and bunkers, all oriented toward the east.
With the insertion of three battalions in the western portion of the area of operation, General Stiles ordered the SLF withdrawn, and by 1825 that evening the BLT completed its withdrawal. Less than 15 hours after the last elements of the BLT left the beach near Nui Dau, the SLF made another amphibious assault, 10 kilometers further north in Duc Pho District.
Following preparation of the beach area and landing zones by naval gunfire and aircraft, the helicopter borne assault elements launched from the USS Iwo Jima at 0830 on 27 February. Two armed UH-lEs escorted the 12 UH-34s and two CH-46s carrying the first wave of Company A into LZ Bat, 1,500 meters from the beach.
As the troop-laden helicopters from HMM-363 made their approach into LZ Bat, enemy soldiers, located in and around the landing zone, opened up with a heavy volume of small arms fire. Marine helicopter crewmen immediately returned fire with their door-mounted machine guns; the UH- lEs closed in to provide suppressive fire with rockets and machine guns.
The first wave of Company A got into 12 Bat at the cost of battle damage to eight medium helicopters. All eight flew back to the Iwo Jima but three made forced landings onto the flight deck. Another three of the damaged aircraft also had to be grounded.
Company C landed by LVTs at 0837. With the beach area safe for helicopters, Company B and the remainder of Company A used the area as their 12. As soon as they reorganized, they moved toward 12 Bat and linked up with the isolated elements of Company A. Enemy sniper fire continued, wounding seven Marines by 1200.
12 Bat remained hazardous for aircraft all morning. At 1030, a UH-34 encountered heavy small arms fire while making an emergency medevac from the zone. Fortunately, it suffered no hits. Around noon, two other helicopters from HMM-363 were not so lucky. The squadron's after action report said:  At 1206H, two aircraft were launched for an emergency medevac from Landing Zone Bat. YZ-81 received five rounds upon approach and had to wave-off. His wingman, YZ-83, then proceeded into the zone, but also en countered heavy fire on approach and, after taking three rounds, waved off. One of the rounds lodged in the co pilot's right thigh causing moderate injury. Shrapnel from the same round hit the co-pilot's left foot and the pilot's chin, causing minor injuries. Both aircraft returned to the USS Iwo Jima with battle damage.
The rest of the BLT continued to land and by mid day the command group was controlling the operation from ashore and the two artillery batteries were set up, ready to support the battalion. Company D landed by helicopter at 1430 and the battalion began to sweep to the southwest.
The SLF remained in almost constant contact with fleeing groups of VC for two days after the landing, but by the afternoon of 1 March the contact diminished. The morning of 3 March the operation terminated. Phase II of Operation Deckhouse VI cost the enemy 76 dead; but they killed a Marine and wounded 50 others.
For Hilgartner's 1st Battalion, 5th Marines, operating inland with the ARVN battalions, the en tire operation had been frustrating. Although the Marines found and destroyed numerous fortifications, they had very little enemy contact. The following excerpt from a report of 2 March typifies the battalion's encounter with the enemy during the period 26 February-3 March:  Company D while sweeping through a hamlet observed 3 VC carrying packs. One VC was dressed in black, one in white, and one in green trousers. The VC spotted the Marines and began to run in a westerly direction. Company D fired 10 rounds of small arms fire and physically pursued the VC. VC wearing green trousers was captured. The VC carried a well-stocked first-aid kit. Marines continued to pursue and captured the VC wearing white trousers. This VC was carrying a pack with assorted clothing. Marines continued to pursue third VC with negative results.

When Deckhouse VI ended on 3 March, the 1st Battalion, 5th Marines, had accounted for 17 Communists killed and 11 captured. The 1st Battalion suffered two killed and 12 wounded.
Both the 1st Battalion, 4th Marines and the 1st Battalion, 5th Marines departed the Duc Pho area after Deckhouse VI. The 1st Battalion, 4th Marines reverted to SLF control while the 1st Battalion, 5th Marines returned to Chu Lai. With the departure of these units, responsibility for the Duc Pho TAOR again rested with the 3d Battalion, 7th Marines.
Desoto Continued
Operation Desoto continued through the months of March and April. The 3d Battalion conducted daily company- and platoon-size search and destroy operations while maintaining and improving the Nui Dang base camp and LSA area and positions on Nui Dau. Throughout this period, brushes with local VC were frequent. Constant pressure by the Marines forced the VC to give up attempts to defend the hamlets and resort to delaying actions, harassment, and only an occasional attack.
The most damaging enemy action during the period took place early in the morning of 24 March when an enemy force hit the battalion base camp and logistic support area with 250 mortar and recoilless rifle rounds. The first rounds landed in the CP/LSA part of the camp. Battery I began counter- battery fire before its gun positions came under fire. The VC quickly responded and fired 70 rounds into the artillery revetments, scoring direct hits on two of the Marine guns, killing three Marines and wounding 14 others. The artillerymen fired more than 100 rounds, silencing the enemy weapons. The effects of the Communist attack remained visible long after the action stopped. The enemy fire had hit the tactical fuel dispensing system and dumps in the LSA; 70,000 gallons of fuel burned far into the night.
The same day, Company K conducted a search and destroy operation northwest of Nui Dau, accompanied by the village chief and National Police representatives. Company G, 7th Marines, which had joined the operation on 23 March, assumed blocking positions outside the village while a plane flew over the village, broadcasting advice to the villagers to remain in their homes.  As the Marines of Company K began moving into the hamlets, they saw several VC slipping into the waters of the Dam Lam Binh and into sampans moored nearby. The Marines captured these, and found 13 more hiding in a bunker. The pilots of UH-1E helicopters supporting the operation saw more Communists camouflaged with moss in shallow swamp water. The gunships made several strafing runs to force the VC toward shore. After each pass, some of the enemy waded to shore to be captured by Company K. The aviators flushed 3 VC from the swamp in this manner and killed another 23. The number of prisoners reached 49 during the operation.
By 31 March, the battalion had swept approximately 75 percent of the assigned area of responsibility. Reconnaissance teams operating in the hills to the west and aerial observers continued to report moving enemy, which supporting arms took under fire with good results. Targets outside the TAOR, acquired through intelligence sources, suffered attacks by Marine radar-controlled air strikes and USAF B-52s. The steady pressure exerted by the Marine infantrymen in the rice paddies and hamlets began to pay dividends. The harassed local Communist forces reverted to guerrilla tactics as evidenced by an in crease in their use of mines and booby traps.
The most costly mining incident during this period occurred at dusk on 5 April. As full darkness approached, Captain Robert B. Wilson began to move his Company G, 7th Marines into a night defensive position on a small hill southeast of Nui Dang. Someone in a security element tripped an antipersonnel mine devised from a 105mm round. The explosion wounded two Marines, one of whom re quired immediate evacuation. Unfortunately, the medevac helicopter, which had been in the area all day, had departed for Ky Ha. Instead, the pilot of a UH- lE gun ship volunteered to make the evacuation.
Captain Wilson suspected there might be additional mines hidden in the chest-high elephant grass on the hill. He advised the UH- lE pilot by radio to hover, rather than land, when picking up the casualty. The pilot hovered just above the ground and several infantrymen loaded the wounded Marine on board. As the loading occurred, a second, larger explosion disintegrated the UH- lE, causing numerous additional casualties. Other nearby Marines rushed to the scene to provide assistance only to be caught by a third explosion as large as the second.
Darkness made it difficult for Captain Wilson to get an accurate casualty count; the reported figure was 10 dead and 13 wounded. (Not until a week later did Marines recover the body of an 11th victim, a crew member of the UH-1E. The crewman's body, still strapped in its seat, lay more than 200 meters from the site of the explosion.
Company G searched the area around the three craters and found two wires leading from the hill to a cane field 500 meters away; the VC had command detonated the last two mines. Analysis of the craters from the last two explosions revealed they had been made by bombs of 250 pounds or larger.
While all the enemy's harassing actions were not as successful as the one on 5 April, Marine casualties were high. Lieutenant Commander Robert M. O'Brien's Company B, 1st Medical Battalion, operating with the Marines at Duc Pho, treated an average of 12 casualties and performed two major surgical operations a day. On one day alone, they handled 49 wounded. One of these casualties, a young Marine who was seriously wounded and under the influence of sedation, asked O'Brien if he would live. A few minutes later the chaplain arrived and, as he approached, heard the wounded man say "Chaplain, I don't need you. The doctor says I'm going to live.
The return of local Viet Cong units to guerrilla tactics was not the only indication of the Marines' growing influence in the region. District officials reported that the populace, enjoying more security, became increasingly pro-Government. Indicative of growing anti-Viet Cong feeling among the people was the fact that they often volunteered information pinpointing VC locations.
Unfortunately, military success outpaced civic action progress, particularly in the resolution of the refugee problem. About 11,000 Vietnamese became refugees from the heavy combat in the Duc Pho area. Of these, local government officials considered about 7,500 as "permanent" refugees who were to be resettled on an island 10 miles off the coast. However, since there were few vessels available to move such numbers, food and housing became critical in the Desoto area of operations.
Local factors complicated the 3d Battalion, 7th Marines' civic action problems. The area was the home of the vice premier of North Vietnam, a fact in which many local Vietnamese took great pride. In addition, intelligence sources gave indications the province chief was a Viet Cong sympathizer, as were many of the refugees. Despite positive efforts by the commander of the Marine battalion, including obtaining new leadership for the attached Army civil affairs platoon, the civic action aspects of Operation Desoto remained unsolved long after the operation ended.
By 7 April, when Operation Desoto ended, the Marines had expanded positive military control over 43 square kilometers of the Duc Pho District and had ensured relatively safe movement in another 50 square kilometers. Revolutionary Development teams were able to work effectively, a virtual impossibility three months earlier. Desoto was a land mark in that it was an initial step toward restoration of Government control in southernmost I Corps.
Logistically, Operation Desoto had been unique. The terrain and tactical situation required that all logistical support be provided by helicopter. At the beginning of the operation, the Marines established a logistical support area at the Quang Ngai airfield, and for the first six days flew all supplies from there directly to units in the field. Thereafter, six CH-46 helicopters arrived daily' from Chu Lai, to supply an LSA at Duc Pho. On 8 February, to preserve the wing's helicopters and conserve critical flight time,
III MAF obtained a Navy logistical support ship which established a forward supply point providing all operational support. The ship, an LST, loaded at Chu Lai with all classes of supply and then stationed itself off the coast, only five miles from the Duc Pho LSA. Helicopters, hovering over the ship, picked up supplies as external lifts and moved them to the LSA. This technique reduced the daily helicopter requirement from six to four. The Navy further improved the system later in February by providing a helicopter refueling capability by mooring an LCU (landing craft, utility) alongside, loaded with two 10,000-gallon reinforced rubber tanks full of aviation gas. Helicopters landing on the cargo deck of the LST could have their fuel tanks filled from the alongside LCU at the same time they reloaded for another mission to Duc Pho. A forward supply point at Quang Ngai backed up the logistic support ship. Bulk items, fuel, and ammunition arrived there by trucks from Chu Lai. A detachment of the Marines' new heavy-lift helicopters, Sikorsky CH-53D Sea Stallions from HMM-265, commanded by Lieu tenant Colonel William R. Beeler, lifted the bulk items to the operational area when required. The new helicopters made possible air transportation of heavy equipment such as Ontos, 15 5mm howitzers, and D-4 Caterpillar tractors for which there had been no previous means of aerial delivery.
Logistical problems during the operation almost equaled the operational difficulties of eliminating the Communists from the area. From 27 January when Desoto began, until 7 April when it ended and control of the area passed to elements of the U.S. Army's 1st Cavalry Division (Airmobile), the Marines killed a reported 383 enemy soldiers. But in terms of American casualties the cost was high 76 Marines died and another 573 received wounds.
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PAUL MARQUIS
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SOURCE CITATION:
THE ABOVE OPERATIONS ARE CREDITED
TO 1/3 COMBAT HISTORY FILE AND THE BOOK, "SEMPER FI VIETNAM"