Hack’s Hardcore Hints #11: Mobile Riverine Force

mpaign Series Vietnam | Hack's Hardcore Hints

In Hack's Hardcore Hints series, David Galster shares some of his scenario design toolkits for Campaign Series: Vietnam, a work-in-progress tactical platoon-scale wargame.

It’s a pleasure, Campaign Series Wargamers,

If you thought the Marine Corps participated with the Navy in the Mobile Riverine Force, you will be surprised to find that it was the 2nd Brigade, 9th Infantry Division instead. They formed part of the Joint Task Force 117, named the "Mobile Riverine Force." Why not the Marines? It is because in 1966, the Marine Corps was already heavily committed  in CTZ I (Quang Tri Province,) as Marine Amphibious Force III. This article provides background information on the Mobile Riverine Force that operated in the Mekong Delta.

Origin of Task Force 117

Viet Cong infiltration of the Mekong delta was a severe problem. The US Navy had two other programs, "Operation Game Warden," and "Operation Market Time," to patrol the Mekong delta waterways to intercept supplies intended for the Viet Cong.

A need for "strike" capability to find and eliminate Viet Cong led to a joint Army/Navy committee to develop operational plans.  The first administrative unit for a "Mekong Delta Mobile Afloat Force," (MDMAF) was commissioned at Coronado, California in September 1966. Not long after, TF-117 was designated with the new title, "Mobile Riverine Force." (MRF)

The MRF would provide "naval" support for infantry brigade plus artillery battalion using the "Brown-Water" Navy's modified landing craft, support ships, and specially designed assault boats. The strike unit would be a self-contained amphibious assault force, with all support elements except aircraft. (To be added later.)

USA Unit Bades

Organization

The 2nd Brigade was commanded by Colonel William B. Fulton, and consisted of the 3rd and 4th battalions, 47th Infantry; the 3rd Battalion, 60th Infantry; and the 3rd Battalion, 39th Artillery. (Towed 105mm howitzers.) 9th Infantry Division was activated for Vietnam duty at Fort Riley, Kansas, in February 1966.

The Navy’s component of TF-117 was a wide variety of ships and boats. The first unit, River Assault Flotilla One (RivFlotONE) was composed of River Assault Squadron 9 (RAS 9) and RAS 11. Each of RAS was sub-divided into two River Assault Divisions: Divisions 91 and 92; Divisions 111 and 112.

RivFlotONE also had a group of support ships including two self-propelled barracks ships, (APB,) a non-self propelled barracks ship, (APL,) two fleet tugs, (YTB,) a landing craft repairship, (ARL,) and a tank landing ship. (LST)

Each RAS had a total of 26 armored troop carriers, (ATC,) five Monitors, two command and control boats, (CCB,) one Refueler ATC, 16 assault support patrol boats, (ASPB,) an artillery barge, and an explosive ordnance detachment. (EOD)

In 1967, Task Group 117.3 was composed of USS BENEWAH (APB-35), USS COLLETON (APB-36), APL-26 with USS KALISPELL (YTB-784) and USS WINNEMUCCA (YTB-785) attached, USS ASKARI (ARL-30), and a supporting LST, plus other support and salvage craft. The MRF base was at Dong Tam on the My Tho River  branch of the Mekong River Delta.

Map of the Mekong River Delta in South Vietnam

Details of Ships and Boats

Armored troop carriers, ATC were the main craft of the RAS. They were modified LCM-6 landing crafts, and were 15 m long and 4.6 m wide. Two diesel engines powered twin propellers.

An ATC could carry a full infantry platoon. Armed with three 20mm cannon or Mk 19 automatic grenade launcher and two 20mm cannon, up to two .50 caliber machine guns and four 7.62mm machine guns, two Mark 18 40mm grenade launchers, plus various small arms, the ATCs not only landed troops, but also re-supplied them and provided fire support during operations.

Armored Troop Carrier (ATC)

The refueling ATC boat was similar, except the well deck space for troops carried pumps and rubber fuel bladders instead. Either diesel fuel for boats or JP-4 for helicopters could be carried.

The "Monitor" provided fire support. These had the same superstructure as the ATC but forward, they had an open well deck, with a Mk 2 Mod 0 Navy 81 mm mortar and two 7.62mm machine guns. A rounded bow replaced the door and ramp. The redesigned bow mounted a 40mm cannon (with a co-axial 50 caliber machine gun) enclosed in a turret. The 40mm was the main gun. In addition, at least two Mark 18 grenade launchers were carried along. Later, Program 5 Monitors replaced the 40mm turret with the 105mm turret of the Marine Corps LVT(H)-6 amphibious tractor (Amtrac).

One modification was called the “Zippo” boat. Instead of the mortar, there were two M10-8 flamethrower turrets, and associated fuel and compressed air equipment. The flamethrowers would burn away the dense foliage along the riverbanks to reveal enemy bunkers. The Zippo was hated and feared by the VC.

The command and control boats, CCB were similar to the monitors, except that the mortar pit was replaced with a radio shack.

In case you are worried, the Campaign Series Vietnam game includes the ATC, Program 4 Monitor, Program 5 Monitor (Howitzer,) Program 5 Flamethrower (Zippo,) and the CCB.

A scenario series called "A week in … The Mekong Delta – May 1967" is planned for Campaign Series Vietnam. It will feature lengthy scenarios dealing with My Tho, Ap Bac 2 Battle, and  operations in the Cam Son Base Area.

An ATC unit for CS Vietnam

Campaign Series Graphic of an ATC

Monitor M-92-1

Monitor M-92-1

The Assault Support Patrol Boat, ASPB was similar in size to the ATC but with a more streamlined hull. The two 12V71 diesel engines drove twin propellers. The superstructure utilized spaced armor and bar armor was fitted later. Crew was 5 men. Early boats had a Navy 81mm mortar or two 7.62mm Mk 21 machine guns or .50 machine guns. The turrets were designed for 20mm guns, .50 machine guns, 7.62mm machine guns, and a 40mm automatic grenade launcher. The ASPB underwent several improvements in armor and armament during the years 1967 to 1971.

The ASPB was employed for ambushes, patrols, special operations, reconnaissance, and escort missions. It was also designed to serve as a minesweeper, and was fitted with a mine countermeasure chain drag. Lighter and faster than the Monitor, the ASPB was not as heavily armed or armored.

Assault Support Patrol Boat

The 328-foot USS Benewah (ABP-35,) self propelled barracks, was built on a World War II LST-542 class hull. Like the riverine craft, fire superstructures of these ships carried the same bar armor to protect them from rockets and recoilless rifle fire. APBs USS Benewah and USS Colleton carried two quad 40-mm guns, two 3”/50 dual-purpose guns,  eight .50 machine guns, and eight 7.62mm machine guns.

Each APB could accommodate about eight hundred troops, and provide support for the riverboat crews. Each APB had an extensive communications system. The USS Benewah (APB-35) was equipped to serve as the brigade and flotilla flagship.

Self-Propelled Barracks Ship

Combat Operations

Typical combat operations involved first sweeping the assault area with the ASPBs for reconnaissance. Monitors follow, and fire on enemy troops to suppress them while the ATCs would move in, and offload infantry assault troops.

Artillery barges would bring the 105mm howitzers to within an effective range, (11000m) and provide support. Reinforcements might be available from a self-propelled barracks ship.

Troops could also be brought in by helicopter to LZs for blocking purposes. A graphic depicting a hypothetical operation is shown below.

Some real operations included  Truong Cong Dinh, in which  Mobile Riverine Forces conducted a series of combined riverine and airmobile operations, beginning east of My Tho. Operations were supported by the 3rd Battalion, 34th Artillery of the US, which established a fire support base on the north bank of the My Tho River, 16km east of the city.

The 4-47 INF Battalion came under heavy small arms and automatic weapons fire just west of My Tho. This continued until 22:25, but the following day, the troops met no VC in the area. In response to new intelligence, moved again into the area of operations, where there were several firefights occurred the rest of the day. The most significant occurred at 17:15 when Company B, 4-47  INF made an assault landing by helicopter, and was fired upon by a VC force from well entrenched positions along the southern edge of the LZ. Five helicopters were brought down. Throughout the evening and into the night, as other elements maneuvered in support of Company B, there was sporadically heavy fighting in the area. At 03:00, the fire support base was attacked by mortars, sinking two artillery barges along with four 105-mm howitzers. The 4-47 INF continued their sweep of the battlefield without finding any VC, and returned by ATCs to the Mobile Riverine Base at Dong Tam in the late afternoon.

Riverine Operations Map

Conclusion

The Mobile Riverine Force was well equipped, with innovative technology. It was a very capable force, and was effective. There were still many challenges for finding Viet Cong, and avoiding ambushes, but several countermeasures were employed like using flamethrowers, to deal with these issues.

References

"The Brown Water Navy in Vietnam - Part 3," by Robert H. Stoner, GMCM (SW)(Ret)

"Mobile Riverine Force," Wikipedia

"Operation Truong Cong Dinh," Wikipedia

"Riverine Warfare- Vietnam I," https://weaponsandwarfare.com/2015/08/26/riverine-warfare-vietnam-i/

Hack was part of the 9th Infantry Division, but not the Riverine Force. He commanded the 4-39th Inf Battalion.

mpaign Series Vietnam | Hack's Hardcore Hints

 

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