The warships of the U.S. Navy closed on the North Vietnamese coast to destroy enemy waterborne logistics craft and coastal lines of communication.

By Lawrence M. Greenberg, contributing editor of Vietnam Magazine.


Napoleon declared that an army marches on its stomach. Contrary to popular mythology, North Vietnamese regulars and Viet Cong guerrillas were not exempt from this time-honored adage. They were dependent on the vast quantities of food and munitions smuggled across South Vietnam's shores and waterways. It was because of this waterborne logistic highway that the destroyers Mansfield and Hanson sailed north toward the 17th parallel before dawn on October 25, 1966.


At 0500 hours, the ships entered North Vietnamese waters and opened a new phase of the war, attacking WBLC (pronounced "wiblic" and meaning waterborne logistic craft and coastal lines of communications) targets still in Communist waters. As part of Operation Sea Dragon, Seventh Fleet destroyers, cruisers and eventually one battleship participated in this new mission between October 1966 and November 1968.


The two warships closed to within 14,000 yards of shore by midmorning and engaged coastal shipping near Dong Hoi. After five hours in North Vietnamese waters, coastal defense batteries fired on the ships at 0951. The Mansfield and Hanson turned to the open sea while their aft 5-inch guns engaged the shore artillery with counterbattery fire. The destroyers escaped unscathed and returned fire on other targets throughout the day, drawing additional, although equally inaccurate, fire twice more that afternoon. North Vietnamese representatives at the United Nations complained to the International Control Commission the next morning about the new U.S. "escalation of war." Despite the protest the operation continued.


By the end of October, destroyers assigned to Operation Traffic Cop, the initial phase of Sea Dragon, sank 101 watercraft and damaged another 94 with 928 5-inch projectiles. During the same period, counterbattery fire accounted for another 426 shells. Seventh Fleet achieved these impressive results without the loss of or damage to a single ship or sailor.


The transition to offensive naval actions in the North evolved from interdiction missions in the South. Since February 1962, U.S. naval warships operating in the Gulf of Thailand located infiltrators and directed the small Vietnamese navy against them below the 17th parallel. After General Maxwell Taylor visited Vietnam in October 1962 as President John F. Kennedy's special military adviser, Operation Beef-up expanded both South Vietnamese and U.S. naval involvement in coastal interdiction.


Despite the emphasis, the February 1965 Vung Ro incident demonstrated inadequacies in the program and showed the importance of waterborne logistics to the Viet Cong. At 1030 on February 16, U.S. Army Lieutenant James S. Bowers, a medevac pilot, sighted a camouflaged ship anchored in Vung Ro Bay along the central coast. Four allied airstrikes on the ship and nearby beach put the 100-ton trawler on her side in shallow water. South Vietnamese troops and a U.S. Special Forces detachment reached the area after considerable delay and found more than 4,000 rifles and machine guns, thousands of cases of ammunition, and a large cache of medical supplies. Aside from the recovered munitions, the operation confirmed large-scale Communist seaborne resupply and led directly to Operation Market Time in mid-March.


Market Time combined U.S. and Vietnamese naval forces against coastal infiltration by the North Vietnamese Naval Transportation Group 125. The Communists used steel-hulled, 100-ton trawlers and seagoing junks to bring supplies south, where they were transferred to sampans and other shallow-draft watercraft for distribution.


One day after JCS (Joint Chiefs of Staff) approval, the destroyers Higbee and Black began coastal patrols supported by daily coastal-reconnaissance flights from Tan Son Nhut. Several days later, Buck seized the first transport, a seagoing junk, just south of the DMZ. Within a month, Market Time expanded to 28 ships under command of Task Force 71 aboard the heavy, guided-missile cruiser Canberra. In addition to destroyers, the operation used Swift patrol craft (PCFs) for close inshore patrolling and absorbed seventeen 82-foot U.S. Coast Guard cutters (WPBs) from U.S. Coast Guard Squadron One in late April. The units patrolled first eight, then nine, coastal sectors covering 1,200 miles and extending 40 miles to sea.


Market Time grew quickly, receiving additional surveillance support from P3A Orions from Sangley Point in the Philippines. Lockheed P-5 Marlin seaplanes from seagoing tenders, and Lockheed P-2V Neptunes from Tan Son Nhut and later Cam Ranh Bay. On August 1, General William S. Westmoreland, commander of MACV (Military Assistance Command, Vietnam), assumed responsibility for the operation and delegated operational control to the commander of the Coastal Surveillance Force. The new unit encompassed Task Forces 71 and 115, already on station off South Vietnam. During the next three years, 15 U.S. Coast Guard high-endurance cutters (WHECs) from U.S. Coast Guard Squadron Three joined the patrols.


A month after the mid-February Vung Ro incident, President Lyndon B. Johnson authorized Pacific Command to implement Operation Rolling Thunder to strike military and logistic facilities in the North below the 20th parallel by air. The primary objective of the operation was to hurt North Vietnam's ability to supply its troops and guerrilla surrogates in the South. At the same time, two smaller and less well-known operations - Yankee Team and Barrel Roll - sought to destroy logistic depots and supply routes in neighboring Laos.


With both Rolling Thunder and Market Time in full swing, Pacific Command tacticians examined the potential for combining the two into a more complete campaign against the North. By mid-1965, the air war caused considerable problems for the Communists, but without an active interdiction program to stop supplies before they reached the South, the overall effect on Hanoi's war-making machine was less than ideal, especially when foul weather restricted air activity. The staff reasoned that the significant naval combat, support, electronic warfare, SAR (search and rescue), and carrier assets already in theater could be used directly against the North to augment Rolling Thunder.


Admiral Ulysses S. G. Sharp, CINCPAC (Commander in Chief, Pacific Command), presented his plan for naval surface interdiction below the 20th parallel to the JCS, which in turn passed it to defense secretary Robert McNamara on May 13, 1966. After two months of debate on the political implications, CINCPAC received permission to engage clearly defined military targets below the demarcation line in the southern half of the DMZ. Although less than Admiral Sharp had hoped for, it was a starting point from which to prove the value of seaborne interdiction in the forward area.


Even though U.S. warships had yet to attack the North, the Communists refused to sit idly by while Seventh Fleet elements manned SAR stations in the Tonkin Gulf beyond North Vietnamese territorial waters. While returning to his carrier on Yankee Station from a mission over the North on July 1, an F-4 Phantom pilot saw three Communist patrol boats making for the Coontz and Rogers on a SAR station 55 miles east of Haiphong. An hour later, F-4s from the Constellation and Hancock attacked the three boats with rocket and cannon fire 10 miles from the two destroyers. All three patrol craft went to the bottom. Coontz and Rogers diverted to the area and rescued 19 survivors, who remained interned in Da Nang until exchanged for American POWs in 1967 and 1968.


Two weeks after meeting with Seventh Fleet Commander Vice Adm. John J. Hyland in Vietnam and three months after strikes began in the lower DMZ, McNamara authorized U.S. seaborne interdiction by two destroyers in North Vietnamese waters up to 17 degrees 30 minutes north latitude. The carriers Oriskany, Franklin D. Roosevelt, Coral Sea and Constellation, all at Yankee Station about 125 miles east of Da Nang, provided support for the warships, Known originally as Operation Traffic Cop, McNamara's order allowed naval forces to engage suspected logistic watercraft but prohibited shore bombardment except in self-defense. Fishing vessels and non-military craft were exempt from attack.


By November, the number of destroyers patrolling the North increased to four. While engaging a target 15 miles above the DMZ on the 4th, the Perkins and Blaine came under close fire from coastal artillery. At 1142, an airburst above the Blaine, sprayed her superstructure with shrapnel and caused superficial damage with no casualties. The destroyers returned fire and called for support from Yankee Station. A 40-minute airstrike leveled the site. One week later, on November 11, the U.S. government expanded the operational area to the 18th parallel and renamed the littoral interdiction program Operation Sea Dragon.


Life aboard Sea Dragon destroyers proved stressful and tiring, yet morale consistently remained high - better, in fact, than morale on similar ships to the south. This resulted from a combination of frequent and true action by destroyer crewmen, immediate results from their efforts, and the possibility of being shot at.


On patrol, one-third of the crew typically remained at battle stations, with at least one gun mount fully manned while the rest ate, slept and performed routine shipboard duties. In the CIC (combat information center, the nerve center of a fighting ship), radarmen kept constant vigil over surface and air search radars, while receiving contact reports from surveillance aircraft and other vessels. Once a target was located and identified, the captain normally ordered general quarters and gave permission to fire. The gunfire direction officer, sometimes aided by spotter aircraft, adjusted spotting rounds before announcing "All mounts, both guns, two salvos." Less than 15 seconds later, 5-inch rounds reached the unfortunate ship or shore target.


Skippers sometimes deviated from this pattern, especially when engaging a single WBLC and if his ship was beyond coastal gun range. In these cases he might engage the target with the ready mount and forego the call to general quarters to save wear and tear on his already well-worked crew.


Just four days after Sea Dragon expanded to the 18th parallel, the JCS changed the rules for engaging shore batteries. This occurred when enemy shore-based search radars "painted" several destroyers with their radar waves, and the U.S. government authorized the ships to attack the sites.


At 1046, December 23, 1966, events took an anticipated but little-publicized turn when the O'Brien took a direct hit from a 57mm shore battery at a range of 7,800 yards. Three minutes later, while engaged in counterbattery fire, she received a second hit that caused moderate damage to the aft deckhouse. A call for assistance went out. At Yankee Station, four carriers launched ready aircraft that suppressed the Communist Artillery. That evening the Benner relieved O'Brien as she retired to Subic Bay for repairs with two dead and four injured.


Sea Dragon destroyers amassed an impressive record by year's end: 382 watercraft destroyed and 325 damaged; five coastal defense batteries destroyed and two damaged; and two radar sites destroyed with another two damaged. Just as significant, the aggressive operation forced a majority of waterborne logistic traffic between Dong Hoi and the South to divert to crowded land routes or into less efficient inland waterways. Also, because of concentrated coastal defense artillery in the limited Sea Dragon area, Admiral Sharp asked the JCS to increase the number of destroyers dedicated to the mission and to enlarge the Sea Dragon area to dilute enemy shore fire.


In mid-January the JCS authorized a third ship for Sea Dragon to provide coverage near the DMZ while the other two patrolled near the 18th parallel, Shortly after the February 8-12 Tet truce - marred on its first day by an exchange between the Stoddard and a coastal artillery site on Hon Mat Island near Vinh - a fourth destroyer and the first cruiser, the 30-knot Canberra armed with two 8-inch/55 triple turrets, five twin 5-inch/38s and four 3-inch/50s, joined the operation. At the same time, the first Royal Australian Navy destroyer joined Seventh Fleet vessels and participated in interdiction and shore bombardment missions on both sides of the DMZ. The additions gave Sea Dragon staying power regardless of air support.


On February 26, McNamara again extended Sea Dragon to include all WBLC targets and certain military facilities ashore below the 20th parallel. The new list of land targets included coastal defense and radar sites, roads, bridges and assorted military command and logistic facilities along the North Vietnamese littoral.


The same day the boundary moved north, the Canberra, Joseph Strauss and Benner hit 16 shore targets 10-12 miles south-east of Thanh Hoa. This was the first time Sea Dragon bombarded shore targets without enemy provocation. Meanwhile, further south, a second destroyer task unit composed of the Duncan and Picking attacked ammunition dumps, barracks and coastal defense sites near Vinh.


While engaging coastal targets 15 miles north of Dong Hoi on March 1, the Canberra came under intense and, this time, accurate shore fire. Just after dark the cruiser took two hits from a range of 11,500 yards. the shells put a 1-inch hole in her deck and damaged several life rafts. The cruiser's 8-inch guns joined the 5-inch guns aboard the Joseph Strauss and Denver to silence the shore artillery. The Canberra was hit twice again 10 days later from 17,000 yards but sustained only cosmetic damage.


In May, Sea Dragon combatants temporarily withdrew south to join Task Unit 70.8.9 in Operation Beau Charger, the largest concentration of U.S. surface ships since the Korean War. During the operation, Canberra combined forces with the light guided-missile cruisers Providence and St. Paul and five destroyers (including Allen M. Sumner and HMAS Hobart) to support Marine amphibious landings and ground sweeps in the southern part of the DMZ. During the assault, the ships suppressed Communist artillery in southern North Vietnam and in the upper half of the DMZ. Back in North Vietnamese waters later in the month, Sea Dragon supplemented a Rolling Thunder attack on the Quang Khe ferry complex that sank more than 40 watercraft.


Midyear 1967 saw a marked decease in coastal traffic that extended well into July. As floating targets declined, Sea Dragon concentrated on those ashore, engaging 518 stationary targets in July, nearly twice the monthly average of that past spring.


Meanwhile, coastal defense sites increased in number and sophistication. By midsummer, American intelligence pinpointed some 105 active and 146 inactive or destroyed sites bounding the Sea Dragon area. Significantly, most now used search and ranging radars. With the improved equipment, Communist gunners began to engage U.S. ships more frequently and at ranges to 15,000 yards. By mid-June, they had fired against Sea Dragon on no fewer than 87 occasions, and the number of ships hit by coastal defense batteries increased. The Dupont lost one sailor and saw nine wounded on August 29. The following month, coastal artillery struck three ships - St. Paul, Damato, and Mansfield - for a loss of one killed and three wounded, along with significant but not ship-threatening damages.


As shore gunnery improved, Sea Dragon units employed new tactics and additional countermeasures of their own. In addition to evasive maneuvers during an attack and engaging targets from a greater distance (averaging 17,300 yards by July), the ships used chaff, electronics and smoke - all with uncertain results.


The fleet also experimented with "Snoopy," a remotely piloted drone used for spotting. Deployed for the first time on July 30 aboard the Mansfield, early models suffered from mechanical problems and a jittery camera that plagued the system. With more engineering and wider application, Snoopy eventually provided the fleet with valuable information. The largest concern during the summer, however, was preparing for the anticipated August-September 1968 arrival of the battleship New Jersey to the line.


October 1967 brought Sea Dragon to the end of its first year and saw the first shore-based damage to an allied ship. The Australian destroyer HMAS Perth suffered four wounded on the 18th. Despite improved North Vietnamese gunnery, sea Dragon statistics were truly remarkable: 2,000 watercraft destroyed or damaged, 3,300 targets ashore bombarded, and 150 running duels with coastal artillery. Moreover, the observed flow of waterborne logistics fell to such a low level (759 in May compared to 200 in October) that Sea Dragon assets were sent south on several occasions to provide naval gunfire support for allied ground operations in and below the DMZ. Not surprisingly, whenever the ships left station, coastal logistic traffic increased until the warships returned.


Operation sea Dragon finished 1967 with 13,976 rounds fired to sink 483 WBLC targets and damage more than 1,000 others. The number of ships involved in sea Dragon at any single time varied considerably and rose as high as eight. Normally, however, the force remained at one cruiser and four destroyers operating in two separate task units.


Pacific Fleet studied Sea Dragon statistics for 1967 and found the average WBLC engagement took place at 18,000 yards, required 29 rounds and involved a 46-foot wooden seagoing junk. The most accurate shooting came, not surprisingly, from the 8-inch cruisers with 20 RPK (rounds per kill) while older 5-inch/38 destroyers took 35 RPK. Newer 5-inch/54 destroyers managed a RPK of just under 28. During 1967, Sea Dragon units spend 1,384 ship days on station and, in addition to WBLC targets, engaged 3,700 land targets, including 300 coastal defense and radar sites.


Keeping the ships supplied with bullets, beans and fuel proved a significant challenge for SERVPAC's (Service Force, U.S. Pacific Fleet) Service Squadron Three and for Seventh Fleet's logistic support force (Task Force 73), already supplying combat and support ships off the South Vietnamese coast.


Navy Support Activity, Da Nang, coordinated ammunition resupply by ammo ships (AEs) from Subic, Guam, Yokosuka, Sasebo and Naval Support Facility Cam Ranh Bay. Many of the 100 deployed ships required ammunition every three days; thus, between 70-90 percent of the replenishment was conducted while underway. During one instance, an AOE replenished the Canberra while the cruiser was engaged in a night-fire mission.


Fuel and provisions arrived in a similar manner on fleet oilers (AOs), AOEs, provision ships (AFs) and combat stores ships (AFSs) from Subic, Yokosuka and Guam. Like their ammo-laden sister ships, the resupply vessels typically steamed circular routes, first replenishing Yankee Station before going on to Chu Lai and Da Nang and finally to Sea Dragon. Replenishment ships spent a nominal 21 days on the 3,000 mile circuit before returning to their out-of-theater depots to refit for the next cruise.


The 1968 Tet Offensive interrupted Sea Dragon operations. Needed desperately to defend besieged allied forces south of the DMZ, all but two destroyers joined a fire-support task force that at one time amassed 22 warships on the gun line. After providing naval gunfire support at Hue, Khe Sanh and along the DMZ, the heavy cruiser Newport News returned to Sea Dragon in March and destroyed a large logistic complex north of the Cua Viet River. After the warm-up exercise, the cruiser and its two destroyers concentrated on targets between the 18th and 19th parallels.


In April, coincidental to the bombing halt above the DMZ, CINCPAC formally reduced the operating area by one-third to below the 19th parallel. The decision was based on fewer WBLC sightings and the need for Sea Dragon ships elsewhere further south.


Despite the drawdown, the interdiction campaign continued routinely through the summer with shore bombardment around Ha Tinh, Vinh and Phu Dien Chau. In August and September, the cruiser and three destroyers struck numerous shore targets and sank or damaged nearly 1,000 watercraft. Then, on September 29th, New Jersey arrived on station with 16-inch guns that could reach 85 percent of the military targets in the north.


The following morning, New Jersey resumed her shore bombardment mission after a 15-year sabbatical since the Korean War. During her first morning with Sea Dragon, the Iowa-class battleship destroyed a supply depot north of the Benhai River, a barracks area, roads, 300 meters of occupied trench lines, and an anti-aircraft battery that made the mistake of engaging a Marine F-4 Phantom while New Jersey lurked nearby. Communist gunners at coastal defense sites learned quickly from the incident and often chose to "abandon site" rather than incur the battleship's wrath.


The world's only active battleship at the time spent a month with Sea Dragon causing havoc along the North Vietnamese coast. Logistic complexes, troop concentrations, fortified caves, watercraft, the famous Thanh Hoa Bridge, and Hon Mat Island's coastal artillery fell victim to New Jersey's 1,900-pound shells. When Washington enacted the November 1, 1968, moratorium on attacks in the North, the battleship moved south to provide heavy naval gunfire support until she left Vietnam in April 1969.


The same order that sent the New Jersey southward also brought Operation Sea Dragon to an end after two years. During its final year, Sea Dragon claimed 1,507 WBLCs destroyed and another 1,535 damaged; 75 coastal defense sites destroyed and another 268 damaged; and destruction or heavy damage to numerous trucks, rail yards, bridges, storage sites, radar sites, and air defense sites.


While carrying out their duties 66 Sea Dragon ships were fired upon by coastal defense batteries in 169 incidents, with 38 ships receiving enemy fire on three or more occasions (for Sumner it was 12 times). Of these, 29 warships were hit, with three ships hit twice. Despite improved accuracy of shore-based artillery, Sea Dragon forces suffered only light casualties - five sailors killed and 26 wounded. Communist gunners failed to put any ship out of commission, although 19 ships withdrew to Japan or the Philippines for repairs.


Coastal interdiction and bombardment of North Vietnam resumed intermittently in the years after Operation Sea Dragon but never at the same sustained level. When U.S. warships did return - for example, in April 1972, the Joseph Strauss and the Richard B. Anderson destroyed the Ben Hai Bridge while the Oklahoma City, Providence, and several destroyers pounded the Do Son Peninsula - they were sent after specific targets and departed the area soon after the mission ended.


All though Sea Dragon failed to stem the flow of men and supplies south, it forced the Communists to divert much of their logistics support to less efficient land routes, primarily the Ho Chi Minh trail. Those stores that continued by water were by and large diverted from coastal waterways to smaller inland rivers that required frequent offloading and portaging to connecting channels. Moreover, the elimination of large-scale coastal infiltration forced Hanoi to employ tens of thousands of potential troops at the less effective business of defending the coast and manhandling mountains of munitions and provisions to Communist forces below the DMZ.