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Source: Wikipedia

Dramatic changes in the course of the war characterized 1968. The enemy's bloody country-wide Tet Offensive of February and March and the follow-up attacks during the spring influenced American decision-making in several important ways. The Johnson administration, convinced that the allied military struggle was faring badly and buffeted by growing domestic opposition to the American role in the war, ordered the gradual withdrawal of U.S. forces from Southeast Asia. At the same time, the administration began diplomatic talks in Paris with the Vietnamese Communist in hopes of achieving a negotiated settlement of the long conflict. U.S. leaders decided that their ability to deal from a position of strength depended on an enlargement and improvement of the South Vietnamese Armed Forces as U.S. forces departed the theater. This "Vietnamization" of the war became the cornerstone of American policy.

The SEALORDS Campaign

As U.S. forces prepared the South Vietnamese military to assume complete responsibility for the war, they also worked to keep pressure on the enemy. In fact, from 1968 to 1971, the allies exploited the Communists' staggering battlefield losses during the Tet attacks by pushing the enemy's large main force units out to the border areas, extending the government's presence into Viet Cong strongholds, and consolidating control over population centers.

The Navy in particular spearheaded a drive in the Mekong Delta to isolate and destroy the weakened Communist forces. The SEALORDS (Southeast Asia Lake, Ocean, River, and Delta Strategy) program was a determined effort by U.S. Navy, South Vietnamese Navy, and allied ground forces to cut enemy supply lines from Cambodia and disrupt operations at his base areas deep in the delta. It was developed by Vice Admiral Elmo R. Zumwalt, Jr., appointed COMNAVFORV in September 1968.

When Admiral Zumwalt launched SEALORDS in October 1968 with the blessing of the new COMUSMACV, General Creighton Abrams, allied naval forces in South Vietnam were at peak strength. The U.S. Navy's Coastal Surveillance Force operated 81 Swift boats, 24 Coast Guard WPBs, and 39 other vessels. The River Patrol Force deployed 258 patrol and minesweeping boats; the 3,700-man Riverine Assault Force counted 184 monitors, transports, and other armored craft; and Helicopter Attack Squadron Light (HAL) 3 flew 25 armed helicopters. This air component was soon augmented by the 15 fixed-wing OV-10 Bronco aircraft of Attack Squadron Light (VAL) 4, activated in April 1969. The lethal Bronco flown by the "Black Ponies" of VAL-4 carried 8 to 16 5- inch Zuni rockets, 19 2.75-inch rockets, 4 M-60 machine guns, and a 20-millimeter cannon. In addition, five SEAL platoons supported operations in the delta. Complementing the American naval contingent were the Vietnamese Navy's 655 ships, assault craft, patrol boats, and other vessels. To focus the allied effort on the SEALORDS campaign, COMNAVFORV appointed his deputy the operational commander, or "First SEALORD," of the newly activated Task Force 194. Although continuing to function, the Game Warden, Market Time, and Riverine Assault Force operations were scaled down and their personnel and material resources increasingly devoted to SEALORDS. Task Force 115 PCFs mounted lightning raids into enemy- held coastal waterways and took over patrol responsibility for the delta's larger rivers. This freed the PBRs for operations along the previously uncontested smaller rivers and canals. These intrusions into former Viet Cong bastions were possible only with the on-call support of naval aircraft and the heavily armed riverine assault craft.

In the first phase of the SEALORDS campaign allied forces established patrol "barriers," often using electronic sensor devices, along the waterways paralleling the Cambodian border. In early November 1968, PBRs and riverine assault craft opened two canals between the Gulf of Siam at Rach Gia and the Bassac River at Long Xuyen. South Vietnamese paramilitary ground troops helped naval patrol units secure the transportation routes in this operational area, soon named Search Turn. Later in the month, Swift boats, PBRs, riverine assault craft, and Vietnamese naval vessels penetrated the Giang Thanh-Vinh Te canal system and established patrols along the waterway from Ha Tien on the gulf to Chau Doc on the upper Bassac. As a symbol of the Vietnamese contribution to the combined effort, the allied command changed the name of this operation from Foul Deck to Tran Hung Dao I. Then in December U.S. naval forces pushed up the Vam Co Dong and Vam Co Tay Rivers west of Saigon, against heavy enemy opposition, to cut infiltration routes from the "Parrot's Beak" area of Cambodia. The Giant Slingshot operation, so named for the configuration of the two rivers, severely hampered Communist resupply in the region near the capital and in the Plain of Reeds. Completing the first phase of the SEALORDS program, in January 1969 PBRs, assault support patrol boats (ASPB), and other river craft established patrol sectors along canals westward from the Vam Co Tay to the Mekong River in Operation Barrier Reef. Thus, by early 1969 a patrolled waterway interdiction barrier extended almost uninterrupted from Tay Ninh northwest of Saigon to the Gulf of Siam.

Allied Navies on the Offensive

The new year witnessed the strengthening of the border patrol barriers and the expansion of SEALORDS into three regions: I Corps, the area north of Saigon, and the remotest reaches of the Mekong Delta. In April, Task Force Clearwater's I Corps efforts were enhanced by Operation Sea Tiger in which Task Force 115 Swift boats, River Division 543 PBRs, Vietnamese Coastal Group 14 junks, and River Assault Group 32 units battled to secure the Cua Dai and Hoi An Rivers in Quang Nam Province. Soon afterward, in June, naval river forces began patrolling the vital Saigon River from Phu Cuong to Dau Tieng, the latter in the hotly contested Michelin Rubber Plantation. This operation, designated Ready Deck, tied in with the Giant Slingshot interdiction effort to the west. In the Mekong Delta proper, Swift boat, PBR, riverine assault craft, SEAL, and Vietnamese ground units struck at the Viet Cong in their former strongholds, which included the Ca Mau Peninsula, the U Minh Forest, and the islands of the broad Mekong River system. From 7 to 18 April, ground, air, and naval units from each of the American services, the Vietnamese Navy, and the Vietnamese Marine Corps conducted Silver Mace II, a strike operation in the Nam Can Forest on Ca Mau Peninsula. The enemy avoided heavy contact with the allied force, but his logistical system was disrupted. After raiding and harassing operations like Silver Mace II, the combined navies often deployed forces to secure a more permanent Vietnamese government presence in vital areas. In June 1969, for example, the U.S. Navy anchored a mobile pontoon base in the middle of the Ca Mau region's Cua Lon River. This operation, labelled Sea Float, was made difficult by heavy Viet Cong opposition, strong river currents, and the distance to logistic support facilities. Still, Sea Float denied the enemy a safe haven even in this isolated corner of the delta. The allies further threatened the Communist "rear" area in September when they set up patrols on the Ong Doc, a river bordering the dense and isolated U Minh area. Staging from an advance tactical support base at the river's mouth, U.S. and Vietnamese PBRs of Operation Breezy Cove repeatedly intercepted and destroyed enemy supply parties crossing the waterway.

By October 1969, one year after the start of the SEALORDS campaign, Communist military forces in the Mekong Delta were under heavy pressure. The successive border interdiction barriers delayed and disrupted the enemy's resupply and troop replacement from Cambodia. The raiding operations hit vulnerable base areas and the Sea Float deployment put allied forces deep into what had been a Viet Cong sanctuary. In addition, American and Vietnamese forces captured or destroyed over 500 tons of enemy weapons, ammunition, food, medicines, and other supplies. Furthermore, 3,000 Communist soldiers were killed and 300 were captured at a cost of 186 allied men killed and 1,451 wounded.

Vietnamization of Naval Operations

The overall composition of the SEALORDS task force in South Vietnam reflected the growing role of the Vietnamese Navy in the war. The newly elected administration of President Richard M. Nixon formally adopted as U.S. policy the Vietnamization program early in 1969. The naval part of that process, termed ACTOV (Accelerated Turnover to the Vietnamese), embodied the incremental transfer to Vietnam of NAVFORV's river and coastal combatant fleet and the logistic support establishment. ACTOV was more than the provision of material, however, for the Vietnamese Navy needed training in the operation, maintenance, and repair of the U.S. equipment and in the efficient functioning of the supply system. Leadership skills at all command levels required improvement as did the general morale of naval personnel before the Vietnamese Navy would be able to fight on alone. Spearheaded by the 564 officers and men of the Naval Advisory Group early in 1969, the U.S. Navy integrated Vietnamese sailors into the crews of American ships and craft. When sufficiently trained, the Vietnamese bluejackets and officers relieved their American counterparts, who then rotated back to the United States. As entire units came under Vietnamese Navy command, control of the various SEALORDS operations passed to that naval service as well.

The allied push into Cambodia during the spring of 1970 brought the SEALORDS forces into a unique operational environment. At 0730 local time on 9 May, 10 days after ground troops crossed the border, a combined Vietnamese-American naval task force steamed up the Mekong River to wrest control of that key waterway from North Vietnamese and Viet Cong forces. The flotilla, led by a Vietnamese naval officer, was composed of American PCFs, ASPBs, PBRs, HAL-3 and VAL-4 aircraft, Benewah, Askari, Hunterdon County, YRBM 16, YRBM 21 and 10 strike assault boats (STAB) of Strike Assault Boat Squadron 20, a fast-reaction unit created by Admiral Zumwalt in 1969. The Vietnamese contingent included riverine assault craft of many types, PCFs, PBRs, and marine battalions. Naval Advisory Group personnel sailed with each Vietnamese vessel. By the end of the first day, Vietnamese naval units reached the Cambodian capital of Phnom Penh, while to the south the combined force stormed enemy-held Neak Luong, a strategic ferry crossing point on the river. For political reasons, no U.S. personnel were allowed past Neak Luong, midway to Phnom Penh. Although the American component pulled out of Cambodia by 29 June, the Vietnamese continued to guard the Mekong and evacuate to South Vietnam over 82,000 ethnic Vietnamese jeopardized by the conflict.

The generally good performance of the Vietnamese Navy during the allied sweep into Cambodia motivated the transfer of significant operational responsibilities to the Vietnamese. The barrier along the Cambodian border was turned over to the Vietnamese Navy in March 1970, which renamed the operation Tran Hung Dao I. In May, Giant Slingshot and Sea Tiger became Tran Hung Dao II and Tran Hung Dao VII. The allied navies also launched Operation Blue Shark, a seven-month effort designed to strike at the Viet Cong command, communication, and logistics network (or infrastructure) in the mangrove swamps at the mouth of the Mekong River system, on the river islands, and along the river banks all the way to the Cambodian border. Coastal Surveillance Force PCFs landed SEALs and LDNN for swift, deadly attacks on the usually surprised enemy. The units often followed up on intelligence gathered by Naval Intelligence Liaison Officers (NILO) assigned to many of South Vietnam's provinces and operational areas.

In July the Vietnamese Navy assumed sole responsibility f or the Ready Deck operation, which was given a Tran Hung Dao designator like the other former SEALORDS areas. Also in July, the U.S. Navy ceased its combat activity on I Corp's Cua Viet and Hue Rivers. The Americans then transferred the last combatant vessels of Task Force Clearwater to the Vietnamese. A final turnover of river craft at the end of 1970 enabled the Vietnamese Navy to take charge of the Search Turn, Barrier Reef, and Breezy Cove efforts deep in the Mekong Delta. Except for continued support by HAL-3 and VAL-4 aircraft and SEAL detachments, the U.S. Navy's role in the SEALORDS campaign ended in April 1971 when Solid Anchor (previously Sea Float and now based ashore at Nam Can) became a Vietnamese responsibility.

The Vietnamese Navy, which grew from 18,000 men in the fall of 1968 to 32,000 men at the end of 1970, instituted organizational changes to accommodate the new personnel, material, and operational responsibilities. The Vietnamese grouped their riverine assault craft in riverine assault interdiction divisions (RAID) and their PBRs into river interdiction divisions (RID) and river patrol groups (RPG). They also augmented the existing RAGs and coastal groups, the latter now consolidated into 20 units for lack of sufficient patrol junks.

This dramatic change in the nature of the allied war effort reflected the rapid but measured withdrawal from South Vietnam of U.S. naval forces. NAVFORV strength dropped from a peak of 38,083 personnel in September 1968 to 16,757 at the end of 1970. As Admiral Zumwalt transferred resources to the Vietnamese Navy, he disestablished U.S. naval commands and airlifted personnel home. With the redeployment of the Army's 9th Infantry Division and the turnover of 64 riverine assault craft in June 1969, the joint Mobile Riverine Force halted operations. When the Riverine Assault Force (Task Force 117) stood down on 25 August 1969, it became the first major naval command deactivated in Vietnam. By December 1970, COMNAVFORV had transferred to Vietnam the remaining river combatant craft in his command, which included 293 PBRs and 224 riverine assault craft. That month, the River Patrol Force was disestablished and the Task Force 116 designator reassigned to Commander Delta Naval Forces, a new headquarters controlling SEAL and naval aircraft units still in-country.

Vietnamese Navy Operational Commands, July 1970
Task Fleet 21 SEALORDS Operations

Units - Operations

Task Force 210 - Special
Task Force 211 - Amphibious
Task Force 212 - Tran Hung Dao I
Task Force 213 - Coastal
Task Force 214 - Giant Slingshot
Task Force 215 - Fleet Command
Task Force 216 - Ready Deck
Task Force 217 - 4th Riverine Area

Source: Winding Down The War - 1968 to 1973
More: Riverine Warfare     Market Time     Vietnamese River Warfare