Operation Coronado XI

Operation Coronado XI was the eleventh of the Operation Coronado series of riverine military operations conducted by the Mobile Riverine Force of the United States and elements of the Army of the Republic of Vietnam, designed to shut down Vietcong strongholds in the Mekong Delta. It ran from 12 February to 3 March 1968. The aim was to conduct riverine, air, and ground search operations in Cai Rang and Phung Hiep Districts of Phong Dinh Province, and to locate and destroy the communists' Military Region III headquarters, and to conduct waterborne cordon and infantry search operations on the island of Cu Lao May in the Bassac River.

Planning
The objective, as developed by the Mobile Riverine Force in co-ordination with the senior US adviser for the IV Corps Tactical Zone, was to conduct riverine, air, and ground search operations in Cai Rang and Phung Hiep Districts of Phong Dinh Province, to locate and destroy Military Region III headquarters, and to conduct waterborne cordon and infantry search operations on the island of Cu Lao May in the Bassac River.

Start
Operation Coronado XI commenced on 12 February 1968, with the movement of the Mobile Riverine Force from Dong Tam to an anchorage in the vicinity of Can Tho. The force proceeded up the Mekong River through the waterway that connects the My Tho and Bassac Rivers, and down the Bassac to Can Tho. The force arrived shortly after 1300 on 13 February, having completed a journey of 176 km from Dong Tam.

On 14 February the two infantry battalions landed from boats and conducted sweeps north along the canals immediately south of Can Tho. Parts of the Army of the Republic of Vietnam 9th and 21st Divisions operated north of the city, sweeping to the southwest. Company A, 3d Battalion, 47th US Infantry Regiment, found a communist cache which contained 460 B-40 rounds, 90 kg explosives, 89 120-mm. mortar rounds, and 225 kg of medical supplies.

During 15–19 February, the Mobile Riverine Force conducted river and air operations west of Can Tho without encountering significant Vietcong forces. When the Can Tho airfield suffered a heavy communist rocket and mortar attack on 16 February, the main task of the Mobile Riverine Force was to sweep the area around the airfield.

On 19 February, at the request of the senior adviser of the IV Corps Tactical Zone, General Eckhardt, Task Force 117 units initiated joint waterborne patrols with units of the Republic of Vietnam Navy River Assault Group along a 21 km stretch of the Can Tho River to halt all sampan traffic. At 2217 an American monitor was struck by B-40 rocket rounds that penetrated the 40-mm. turret. Although seven people, including a RVN interpreter, were wounded, the monitor was able to suppress the communist automatic weapons and small arms fire. The patrols continued throughout the night in an effort to prevent the escape of Vietcong units.

On 22 February the Mobile Riverine Force and RVN armed forces initiated a riverine and air operation in Phung Hiep District to locate the communists' Military Region III headquarters. The 3d Battalion, 50th Infantry, and the 3d Battalion, 47th Infantry, moved into position by the Saintenoy Canal. Fire support was provided by Battery C, 2d Battalion, 35th Artillery, and 3d Battalion, 35th Artillery.

For the boats to pass the low Phung Hiep Bridge, the ARVN engineers raised the center span of the bridge with jacks. As the assault boats proceeded west from Phung Hiep, sporadic communist sniper fire from the north bank of the canal wounded four US Navy personnel. The riverine movement beyond the bridge apparently caught the Vietcong off-guard. When Companies B and C, 3d Battalion, 47th Infantry, beached along the Lai Hieu Canal, just northeast of Hiep Hung, the communists were in bunkers facing the opposite direction towards the rice paddies in anticipation of airmobile attacks. The Viet Cong ran into the open fields away from the canal where they suffered heavy casualties at the hands of artillery and gunships. No US casualties occurred during this action.

On 23 February, the Mobile Riverine Force stopped their attempt to locate Military Region III headquarters and withdrew from the area. Throughout the day there was no sight of the communists or their infrastructure, as the Americans penetrated the deepest into the Mekong Delta they had been.

Second phase
On 24 February the Mobile Riverine Force conducted a waterborne cordon and search operation on the island of Cu Lao May during which both infantry battalions conducted medical and dental civil action programs at enclosures where Vietnamese were detained for questioning in an attempt to win over the population. There was no military contact with the communists in this one-day operation. Northwest of Can Tho on 26 February, the Mobile Riverine Force met a large Vietcong force. Company B, 3d Battalion, 60th Infantry, landed under fire, suffering many wounded men and 12 damaged helicopters. Other elements of the Mobile Riverine Force moved to support Company B; Company E was airlifted at 1130 and landed approximately 800 m east of Company B and Company A followed at 1405. At 1545, more than five hours after the initial skirmish, Companies B and E were still heavily engaged and did not link up until 1705, and because of the number of casualties sustained by Company B, it was placed under the control of Company E. Companies A, B, and E established a night defensive position and were resupplied by 2200. The 3d Battalion, 47th Infantry, to the northwest encountered little fire throughout the day, and its scheme of maneuver was modified to allow it to provide additional support to the 3d Battalion, 60th Infantry.

Task Force 117 meanwhile had established patrols on the Can Tho River along the southern boundary of the operations area to prevent the communists from escaping. About 2030 an armored troop carrier (ATC) was hit in the port bow causing an explosion. An assault support patrol boat went to the aid of the ATC and hit by communist automatic weapons fire. They returned fire was shut down the communists. Ten minutes later a second ATC was fired upon and missed by a recoilless rifle. The ATC immediately returned and suppressed the fire. There were no American casualties in either attack. The American units continued their patrols without incident until 0215 when a major action occurred as a large communist force attempted to escape. An assault support patrol boat came under heavy fire from both banks and sustained several 13–40 rocket hits, causing heavy flooding and wounding two crewmen. Other river assault craft moved into the area and suppressed the communist fire, but one assault support patrol boat sank as it was being towed by a monitor. All crew members were rescued, but the monitor received several hits while moving to assist the disabled assault support patrol boat. During the same period, another assault support patrol boat, operating four kilometers east of the first attack, was hit by heavy communist rocket and automatic weapons fire. The boat captain and radio men were killed and the three other crewmen were wounded but were able to beach the boat. The communist attack lasted 90 minutes, with four US assault craft involved in the battle. A light helicopter fire team was called in to help to cut down the enemy fire.

The Vietcong were unable to escape south across the Can Tho River and continued to suffer casualties as the American blockade was maintained successfully throughout the battle. During the night the Vietcong continued harassing the Mobile Riverine Force battalions with probing attacks and sniper fire. On 27 February the area was swept again, confirming additional enemy losses and discovering caches, including 5 crew-served weapons, 16 small arms, and assorted ammunition.

On 1 March, also, other elements of the Mobile Riverine Force and three Vietnamese Ranger battalions operated around 5 km southwest of Can Tho. Heavy fighting developed in the afternoon and continued into the night. The communists slipped away before dawn and only scattered groups were found by the Americans the next day. During the operation, the South Vietnamese IV Corps provided for evacuation of dead and wounded and responded to all logistics needs of the Americans.

Within the Can Tho area, most movements by water were accomplished without significant opposition because the communists had not prepared fighting positions near the canals. However, had taken thorough defensive measures against airmobile operations conducted near open rice paddies. Bunkers were well constructed, with good overhead protection against artillery and air strikes.

The Vietcong characteristically used an initial heavy volume of automatic weapons fire, followed by sporadic sniper fire. Sniper fire was directed especially at unit leaders and radio operators. The Vietcong continued to fight until the late hours of the night, from 2200 to 2400. They then withdrew but continued to harass American positions with mortar and rocket fire. All American operations conducted in the Can Tho area used maximum naval and air assets.

Coronado XI ended on 3 March when the Mobile Riverine Force left the Can Tho area for Dong Tam. From 4 to 6 March the force assumed the division reserve role while the 3d Battalion, 47th Infantry was replaced by the 4th Battalion, 47th Infantry in the rotation of battalions.