Brown Water Navy in
Robert H. Stoner, GMCM (SW)(Ret)
naval war in
At the same time, the United States Navy found itself embroiled in a war that was fought at first, off the coastal waters of South Vietnam, and then in the river deltas, smaller waterways and canals of the country. To combat North Vietnamese infiltration of men and supplies by sea, three Task Forces were formed: TF-115 called Operation MARKET TIME; TF-116 called Operation GAME WARDEN; and TF-117 called the MOBILE RIVERINE FORCE (a joint amphibious Army-Navy riverine operation).
MOBILE RIVERINE FORCE
In March 1966 a joint committee of
Army and Navy personnel drew up tentative plans for the establishment of a
Mekong Delta Mobile Afloat Force (MDMAF). On 1 September 1966, the first
administrative unit of the new MDMAF was commissioned at
The purpose of the MRF was to support an infantry brigade and an artillery battalion using 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 [added later]. Because the Marines were heavily engaged in I Corps, a brigade from the Army’s 9th Infantry Division was chosen as the infantry component of the MRF.
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 (
In 1967, Task Group 117.3 was
composed of USS BENEWAH (APB-35), USS COLLETON (APB-36),
Above: The headquarters for the MOBILE RIVERINE FORCE was the joint Army-Navy base located at Dong Tam, just up river from the city of My Tho on the way to Vinh Long.
Below: A detail
map of the Dong Tam base. The boat
turning basin is the square-shaped blue area just off the large canal that
joins the My Tho River. The city of
Above: The Dong Tam base. The Navy side is in the foreground with the boat turning basin. The Army side is in the background. [Photo: Jerry Laviviere]
The MRF continued to grow to full
strength during 1968 with the addition of two more River Assault Squadrons (
Boats of the MRF
The main craft of the
All the riverine boat conversions were well protected with both conventional and “stand-off” armor. This “stand-off” or bar armor was a series of 1-inch concrete reinforcing steel rods set about 12 to 18 inches from the boat’s hull and superstructure. The bar armor was designed to detonate an RPG (rocket propelled grenade) or recoilless rifle rounds before they hit the armor plate. “Stand-off armor” proved to be very effective against both hand held and crew served weapons used by the VC, and significantly reduced casualties and damage when an riverine craft was hit by enemy fire.
Some ATCs were modified with a helicopter flight deck counted over the troop wells (called Program 5). This was done initially to provide a platform for helicopters to land on for delivery of supplies and transfer of personnel. Almost immediately, helicopters were pressed into service for casualty evacuation since they were often the only place for a helicopter to land during operations in the Delta. Some of the ATCs with helicopter pads were designated ATC(H)s. The ATC(H) was fitted as battalion aid station and carried a doctor and either Army medics or Navy corpsmen. One ATC(H) also carried refrigerated whole blood and there was always a fully equipped operating table ready to perform emergency surgery.
Each river squadron had an ATC fitted-out as a refueler. The refueler ATC carried bladders of combat gasoline (mogas) or aviation fuel (avgas) under the flight deck to refuel the squadron’s boats, assault craft, and sometimes helicopters. The refuelers proved indispensable during prolonged operations and pumped huge quantities of fuel to keep the riverine forces on station.
The fire support vessel of the MRF was the Monitor. These had the same superstructure as the ATC, but were completely different forward. The monitor had an open well deck, forward of the superstructure, that contained a Mk 2 Mod 0 Navy 81 mm mortar and two 7.62mm machine guns. A rounded bow replaced the bow ramp of the ATC. 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 of the riverine forces and it provided a high volume of fire during landing operations. In addition, at least two Mark 18 grenade launchers were carried along with the individual weapons of the crewmen. Later, Program 5 Monitors replaced the 40mm turret with the 105mm turret of the Marine Corps LVT(H)-6 amphibious tractor (Amtrac).
Initially, an ATC was used to test an
Army M132A1 flamethrower armored personnel carrier (
Two Monitors in each squadron were also fitted out as Command Control Boats (CCBs). The only major difference between a regular Monitor and a CCB Monitor was the removal of the mortar pit aft of the 40mm turret. In its place a command and control shelter was fitted to serve as the command post for the battalion and task group commanders during an operation. The CCB Monitor was almost identical to a regular monitor and carried out much the same function.
The Assault Support Patrol Boat (ASPB) was specially constructed for use by the riverine forces. 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. It carried a single 20mm cannon and twin .50 caliber machine guns or 20mm cannon in two turrets, one in the bow, and one atop the superstructure. The 81mm mortar was mounted in the stern and a combination of 7.62mm machine guns or Mark 18 grenade launchers were also carried in place of the mortar. The ASPB had a unique underwater exhaust system that made it the quietest of the riverine boats.
The ASPB was employed for ambushes, patrols, special operations, reconnaissance, and escort missions. Later in the war, pairs of single .50 caliber machine guns replaced the 7.62mm machine guns on the stern while the forward gun turret received eight 3.5-inch rocket launchers (Mk 47) mounted on their sides. Linked to the machine guns the rocket launchers could be targeted by elevating or depressing the machine guns and traversing the turret.
Ships of the MRF
The MOBILE RIVERINE FORCE had a
number of support ships and craft. The self-propelled barracks ships (APBs)
were purpose-built on LST-542 class hulls to berth a battalion of troops. Built in World War 2, they were modified for
However, since these barracks ships
could not handle all the men of the infantry battalions, and artillery
batteries, another non-self propelled barracks ship (
To service and repair the various
riverine boats and landing craft a repair ship was assigned to the support
section of the task force. The job fell to the
The last major support vessels of Task Force 117 were 1156-Class LSTs assigned to the flotilla from the 7th Fleet. These provided additional storage space that was unavailable on the APBs. The LSTs housed supplemental supplies of ammunition, weapons, spare parts, and rations for the riverine forces during prolonged operations. The LSTs were equipped with a flight deck and carried the brigade’s helicopter detachment of four helicopters and one company of infantry. The LSTs also supported a River Assault Division.
The final components of the MRF were the artillery and helicopter barges developed by the Army. The Army quickly discovered that the soggy terrain of the Mekong Delta was not suited to either artillery or helicopters. An Army artillery officer had a fire support barge fabricated from sections of two Ammi pontoons that enabled a pair of 105 mm howitzers to fire while anchored next to the shoreline. These barges could also be beached if the tide went out. Helicopters faced a similar problem because there were few areas for them to land. The ATC(H) provided a partial solution. A helicopter barge was developed using sections of Ammi pontoons. Each of these helicopter barges could accommodated three UH-1 helicopters and was equipped with a refueling system that carried 1,500 gallons of JP-4 aviation fuel. Army LCM-8 landing craft were used to move the artillery and helicopter barges about and to supply the barges with fuel and ammunition. The MRF did not lack for artillery or helicopter support.
Ships of the MRF: APBs (4),
BENEWAH (APB-35) - class Self-Propelled Barracks Ship
Above: The 328-foot USS BENEWAH (
Below: BT2 John Hardy stands next to his .50 machine gun on USS BENEWAH in 1968. The arch-shaped tubes are limit stops for the machine gun. Personal radios were common entertainment aboard ship. [Photo: John Hardy]
Below: USS BENEWAH shown with her brood of riverine craft nested alongside the Ammi pontoons tied to her starboard side. [Photo: John Hardy]
Below: USS NUECES (
Above: KALISPELL (YTB-784) closest to camera, USS WINNEMUCCA
(YTB-785) inboard of YTB-784, and a Light Salvage Lift Craft (YLCC-1) of Harbor
Below: YRBM-17 (left) and
Above: A composite photo of USS ASKARI (
LST – Landing Ship Tank, LST-542 class, LST-1156 class
The ships that brought the supplies to the various ships of the MRF and acted as floating supply, fuel, and ammunition storage were the LSTs. The MRF always had at least one LST-1156 class (and sometimes two) assigned to it from Amphibious Ready Group BRAVO. The LST-1156 class ships were improvements over the LST-542 class World War 2 designs. These later LSTs came into service towards the end of the Korean War and shortly thereafter. They were quite different in appearance from their World War 2 cousins.
Below: USS KEMPER COUNTY (LST-854) off Vung Tau in 1967. Most of the WW2 LSTs carried a crane on the
top deck to assist with off-loading of supplies or lifting large, heavy objects
aboard ship. Like all LSTs,
Above: USS WINDHAM COUNTY (LST-1170) off the coast of
AKL – Attack Cargo Light, Camano-class
Above: Two of the hardest working ships of the MRF were the
USS BRULE (AKL-28), shown here, and the USS MARK (AKL-12). Both were small Camano-class light freighters
built for the
ASPB – Assault Support Patrol Boat
ASPB was designed for operations in
Above: A drawing of a typical ASPB as it appeared in 1967. The Mk 48 Mod 2 turret on the bow carried two .50 machine guns, the Mk 48 Mod 0 turret aft of the coxswain’s station carried either a Mk 16 Mod 4 20mm gun and a Mk 21 Mod 0 7.62mm machine gun or a Mk 19 Mod 0 40mm grenade launcher. [Drawing: Windjammer Arts]
Below: A nest of Vietnamese ASPBs alongside YRBM-20 about 1970. These boats are showing signs of a lot of hard use. Note the muddy water. [Photo: Kent Hawley]
Above: In late 1969 many ASPBs were fitted with eight (4x2) 3.5-inch rocket launchers Mk 47. This boat has the Mk 48 Mod 2 turret with the twin .50 machine guns. Rockets were either HEAT (high-explosive, anti-tank) or WP (white phosphorus). [Photo: Tom Lefavour]
Below: The Mk 48 Mod 2 turret with Mk 47 3.5-inch rocket launch tubes. The Gunner’s Mate holding a 3.5-inch rocket is explaining the new modifications to the boat crew. The “lumps” on the back of the rocket launch tubes are the contactor latch groups. Each one holds a rocket in the tube and provides a firing contact for the rocket motor. [Photo: Tom Lefavour]
Below: A Mk 48 Mod 0 turret on the bow of an ASPB mounts a 20mm Mk 16 gun and a 7.62mm Mk 21 machine gun. [Photo: Mike Gregory]
Above: The MSR (Minesweeper, River) was a conversion of the standard ASPB. These were used as a command and control boat for the MSD (Minesweeping Drone). The MSD was a 23-foot remote-controlled minesweeping boat powered by a 327 Chevrolet gasoline engine. The MSR differed from the standard ASPB by the addition of specialist minesweeping gear and electronics. Also the upper 20mm turret was replaced by two 7.62mm machine guns. Mine Division 113 of Mine Squadron 11 used the MSR boats. This boat is MSR-7. [Photo: Jack T. Walker]
Below: Three MSDs of Mine Division 113. The MSD was designed to sweep different types of river mines and not put a crew at risk. It was designed to be run remotely from a control boat and was considered expendable. The MSD was also capable of manual operation. [Photo: Tom Lefavour]
Above: MSDs of Mine Division 113 operating in manual mode with crews. Keeping the main waterways swept of mines was hot, dirty, tiring, tedious and punctuated with moments of sheer terror. [Photo: Tom Lefavour]
Below: The MSD used a 327 Chevy engine and MerCruiser stern drive. The circular tube is a propeller guard. The hull of the MSD was non-magnetic. [Photo: Tom Lefavour]
ATC – Armored Troop Carrier
The ATC was a modified LCM-6 landing craft. It was 56 feet long by 14 feet wide and was powered by two diesel engines driving twin propellers. All versions carried a chain minesweeping dragline for cutting cables of command-detonated mines in canals. The ATC had an armored superstructure that had gun tubs for .50 machine guns, 20mm cannon, or 40mm automatic grenade launchers. Early ATCs [Program 4] were called “rag tops” due to the fabric cover over the well deck of the boat. Later boats replaced the soft top with a hard top [Program 5] capable of landing a UH-1 helicopter. Called the ATC(H) for helicopter, some of these boats were pressed into service as a battalion aid station with doctors and medics to take care of wounded sailors and soldiers.
Each squadron had a refueling boat using an ATC boat. Instead of troops, the well deck of the boat carried pumps and rubber fuel bladders with diesel fuel for boats or JP-4 for helicopters. During long operations, these boats would help keep the boats of the squadron running and the helicopters flying.
on, two ATCs were modified to field flamethrowers. 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 simplest conversion was the
removal of the soft top on the ATC (T-91-8 and T-112-5) and an M132A1
Another ATC conversion was the “Douche Boat” that was armed with two high-pressure water cannons. The water cannons were used to wash away enemy bunkers and fortifications along the riverbanks. The boat had an auxiliary diesel engine mounted in the well deck that drove the high-pressure water pump that fed the two water cannons. A water induction tube was located on the left side of the boat with a pivoting pickup strainer head for river water.
Below: “Irma La Douche” was a “rag top” ATC with two water cannons. The tall, curving pipes just in back of the soft top are the water cannons. [Photo: Ray F. Longaker, Jr.]
Above: A test run of the converted Douche Boat. The water inductor pipe is down (left corner of stern) and its right water cannon at full pressure. In this photo, the soft top has been removed from above the well deck. The water pressure from the cannon is actually causing the boat to list to port. [Photo: Mike Harris]
Below: A model of the Douche Boat shows the location of the third engine and water pump for the water cannons. The inductor and its pipe are shown running along the top, portside of the hull. The brown boxes behind the bar armor are C-ration cases. [Model: Ray F. Longaker, Jr.]
Above: Tango T-91-8 is shown with an M132A1 flame
Below: A close-up of the M132A1 “flame track”
Below: Another Tango boat, T-111-7, was converted to mount two M10-8 flame guns on top of a modified bow. The fuel bladder for the liquid napalm and compressed air tanks were put under armor in the well deck. This is the ATC conversion to a Zippo boat after its turnover to the Vietnamese. The bar armor has been extended around the bow to protect the flame guns, the two are shown on the raised platform on the bow. The deckhouse behind the flame guns is for the boat crew. [Photo: Tom Lefavour]
Above: Another Zippo was a conversion of a
Below: A nest of ATC(H) boats. The Program 5 boats were assigned to
Above: An ATC(H) of
Below: A Program 5 ATC(H), Tango-152-1 of
Below: Another landing platform for helicopters was the helicopter barges of the Army’s 9th Division. These were made from two Ammi pontoons. Here is one of the division’s OH-23 Raven helicopters on one of those improvised landing platforms. The barges were towed by Army LCM-8 landing craft. [Photo: Larry Webb]
Above: Brigadier General William B. Fulton, 2nd Brigade, 9th Infantry Division, confers with one of his officers. The starboard bow of the helicopter barge pusher LCM-8 is shown in the foreground with its bow ramp down. The converted Ammi pontoon helicopter barges could land three helicopters and could provide 1,500 gallons of JP-4 to refuel them during action. [Photo: Larry Webb]
Below: Sometimes the helicopters couldn’t set down on the barges and pilots had to improvise. Here a UH-1D medical evacuation helicopter (“Dustoff”) hovers above an Army LCM-8 pusher boat to pickup wounded troops. [Photo: Lee Wahler]
Monitors, CCBs, and Zippo Boats
The first Monitors and Command and Control Boats (CCB) were very similar in construction. The main recognition point was the 81mm mortar pit aft of the 40mm turret on the Monitor and a radio communications shelter in place of the mortar pit on the CCB. Initially, two of these Program 4 Monitors were converted by replacing the mortar pit with two M10-8 flame guns to become Zippo boats. Later, Program 5 Monitors were converted to Zippo boats by replacing the forward gun turret with two M10-8 flame guns.
As originally built, the Program 4
Above: Monitor M-92-1 in 1968 showing the lines of the first Program 4 Monitor boats. The tube sticking up to the left of the standing sailor is the 81mm mortar. A 7.62mm machine gun is under the gun cover to the rear of the mortar. [Photo: Ron McAbee]
Below: CCB C-91-1 in this 1967 photo shows the similarity to the Monitor. The CCB had multiple radio antennas around the communications shelter that replaced the mortar pit on the Monitor. CCB C-91-1 was a Program 4 boat and the first command and control boat delivered to the newly formed MRF. Note the armored doors of both the turret and communications shelter are opened due to the oppressive heat and humidity. [Photo: Dan Dodd]
Above: The first of the Program 4 boats of the MRF were Monitor M-91-1 (left) and CCB C-91-1 (right). This side-by-side shot shows both similarities and differences between the two kinds of craft. [Photo: Doug Lindsey]
Below: The Program 4 Monitor M-92-2 became a Zippo with the addition of two M10-8 flame guns behind the 40mm turret. This series of photos shows the Zippo conversion clearing the shoreline growth to expose bunkers. [Photos: Don Blankenship]
Above: The aft Mk 48 Mod 0 turret on a Program 5 Monitor was surrounded by bar armor. In the left photo, the crew has installed sandbags between the bar armor and armor plate to increase the armor protection. The improvised sandbag armor was not particularly effective. The right photo shows the business end of the 20mm Mk 16 gun and the co-axial 7.62mm machine gun. As seen in the photos, some gunners took the cone-shaped flash hider off their guns (left), while others kept it on (right). [Photos: Steve Lovey (L), Dave Hazelett (R)]
Below: A good close-up bow shot of Monitor 2 at SEA FLOAT in early 1970. Note the protective bar armor around the 105mm turret and the twin .50 machine guns mounted on top. This was an uncommon field modification but very wise considering operational area. [Photo: Bill Patterson]
Above: A still closer look at the 105mm turret and twin .50 machine guns of Monitor 2. This boat was turned over to the Vietnamese in November 1970. [Photo: Bill Patterson]
Below: The Program 5 Monitor and Zippo boats were very
similar. Here are two sitting
side-by-side for comparison with the Zippo on the left (flame guns covered) and
the Monitor on the right.
Above: A close-up photo of Zippo Z-132-1 showing both M10-8 flame guns. The flame tube is on the right and the co-axial 7.62mm machine gun is on the left of the flame tube [as seen from the front]. The Zippo could carry over 1,100 gallons of napalm. [Photo: Dewey Pollack]